Maybe you've spoke of this subject B-4.

But I see Lowes big box store has a variety of instant hot water
heaters. The one like Rinnai sp...

Are these water heaters worth the price to switch out from a water tank?

There are various models and prices...
Have you had any experience with any at all? Are they efficient? Is
Rinnai the only one to trust?

Seems to me that a great deal of money can be saved using these heat on
demand
units...am I wrong?

Please comment on what you know.

And I thank you for any input...

Pat in Denver

On Nov 20, 3:25*pm, (Papa Pat) wrote:
Maybe you've spoke of this subject B-4.

But I see Lowes big box store has a variety of instant hot water
heaters. The one like Rinnai sp...

Are these water heaters worth the price to switch out from a water tank?

There are various models and prices...
Have you had any experience with any at all? Are they efficient? Is
Rinnai the only one to trust?

Seems to me that a great deal of money can be saved using these heat on
demand
units...am I wrong?

Please comment on what you know.

And I thank you for any input...

Pat in Denver

The saving with instantaneous heaters is that you don't incutt
"standing losses", ie heat losses from a tank of hot water standing
around.
The amount you save depends on your usage pattern. If you use little
hot water and the hot water tank is permanently on, then there are big
savings to make.
They also depend on how well your tank is insulated.
Losses from instantaneous water heaters are virtually nil.
Losses from stored water heaters are almost constant regardless of how
much you use.
In the UK, virtually all hot water in domestic houses comes from
instantaneous gas fired water heaters in new installations/new
boilers.


http://en.wikipedia.org/wiki/Combi-boiler#Combination_boilers

Papa Pat wrote:
Maybe you've spoke of this subject B-4.

But I see Lowes big box store has a variety of instant hot water
heaters. The one like Rinnai sp...

Are these water heaters worth the price to switch out from a water tank?

There are various models and prices...
Have you had any experience with any at all? Are they efficient? Is
Rinnai the only one to trust?

Seems to me that a great deal of money can be saved using these heat on
demand
units...am I wrong?

Please comment on what you know.

And I thank you for any input...

Pat in Denver

I have been using one at work in the garage.
Fine for instant warm(not hot) water to wash
your hands.
So it depends on the type and usage .

On Nov 20, 11:32*am, harry wrote:
On Nov 20, 3:25*pm, (Papa Pat) wrote:





Maybe you've spoke of this subject B-4.

But I see Lowes big box store has a variety of instant hot water
heaters. The one like Rinnai sp...

Are these water heaters worth the price to switch out from a water tank?

There are various models and prices...
Have you had any experience with any at all? Are they efficient? Is
Rinnai the only one to trust?

Seems to me that a great deal of money can be saved using these heat on
demand
units...am I wrong?

Please comment on what you know.

And I thank you for any input...

Pat in Denver

The saving with instantaneous heaters is that you don't incutt
"standing losses", ie heat losses from a tank of hot water standing
around.
The amount you save depends on your usage pattern. *If you use little
hot water and the hot water tank is permanently on, then there are big
savings to make.
They also depend on how well your tank is insulated.
Losses from instantaneous water heaters are virtually nil.
Losses from stored water heaters are almost constant regardless of how
much you use.


Make up your mind Harry.

1 - First you said the essential difference was the standby losses.
2 - Then you said how much you save depends on your usage patterns.
3 - And then you said losses from tank heaters are almost constant
regardless of how much you use.

For the record, I agree with 1 and 3.

For me, I look at my gas bill in summer, when all gas is used for is
the water heater and my outdoor gas grill. It's about $17 or so a
month and that is with a std efficiency water heater. That includes
those standby losses and usage. I could surely do better with a high
efficiency tank type. From that, I've concluded if I need a new
one, I'd go with a tank type higher efficiency one.

One simple test to settle the standby loss issue would be to read the
gas meter before going away for a few days to a week. Before doing
that, draw enough water to fire it up. Upon returning, see how much
gas it used.

On Nov 20, 12:30*pm, wrote:
On Nov 20, 11:32*am, harry wrote:





On Nov 20, 3:25*pm, (Papa Pat) wrote:

Maybe you've spoke of this subject B-4.

But I see Lowes big box store has a variety of instant hot water
heaters. The one like Rinnai sp...

Are these water heaters worth the price to switch out from a water tank?

There are various models and prices...
Have you had any experience with any at all? Are they efficient? Is
Rinnai the only one to trust?

Seems to me that a great deal of money can be saved using these heat on
demand
units...am I wrong?

Please comment on what you know.

And I thank you for any input...

Pat in Denver

The saving with instantaneous heaters is that you don't incutt
"standing losses", ie heat losses from a tank of hot water standing
around.
The amount you save depends on your usage pattern. *If you use little
hot water and the hot water tank is permanently on, then there are big
savings to make.
They also depend on how well your tank is insulated.
Losses from instantaneous water heaters are virtually nil.
Losses from stored water heaters are almost constant regardless of how
much you use.

Make up your mind Harry.

1 - *First you said the essential difference was the standby losses.
2 - Then you said how much you save depends on your usage patterns.
3 - And then you said losses from tank heaters are almost constant
regardless of how much you use.

For the record, I agree with 1 and 3.

For me, I look at my gas bill in summer, when all gas is used for is
the water heater and my outdoor gas grill. *It's about $17 or so a
month and that is with a std efficiency water heater. That includes
those standby losses and usage. *I could surely do better with a high
efficiency tank type. * *From that, I've concluded if I need a new
one, I'd go with a tank type higher efficiency one.

One simple test to settle the standby loss issue would be to read the
gas meter before going away for a few days to a week. *Before doing
that, draw enough water to fire it up. * Upon returning, see how much
gas it used.



- Hide quoted text -

- Show quoted text -- Hide quoted text -

- Show quoted text -

or tturn existing tank to vacation, come back a day or two later.

how warm is the water?

standby losses are overstated, in a heated basement standby loss helps
to keep your home warm in winter..

On Nov 20, 12:26*pm, " wrote:

snip

standby losses are overstated, in a heated basement standby loss helps
to keep your home warm in winter..

That's worth repeating for the logically impaired.

standby losses are overstated, in a heated basement standby loss helps
to keep your home warm in winter..

Joe

On Nov 20, 12:26*pm, " wrote:
On Nov 20, 12:30*pm, wrote:





On Nov 20, 11:32*am, harry wrote:

On Nov 20, 3:25*pm, (Papa Pat) wrote:

Maybe you've spoke of this subject B-4.

But I see Lowes big box store has a variety of instant hot water
heaters. The one like Rinnai sp...

Are these water heaters worth the price to switch out from a water tank?

There are various models and prices...
Have you had any experience with any at all? Are they efficient? Is
Rinnai the only one to trust?

Seems to me that a great deal of money can be saved using these heat on
demand
units...am I wrong?

Please comment on what you know.

And I thank you for any input...

Pat in Denver

The saving with instantaneous heaters is that you don't incutt
"standing losses", ie heat losses from a tank of hot water standing
around.
The amount you save depends on your usage pattern. *If you use little
hot water and the hot water tank is permanently on, then there are big
savings to make.
They also depend on how well your tank is insulated.
Losses from instantaneous water heaters are virtually nil.
Losses from stored water heaters are almost constant regardless of how
much you use.

Make up your mind Harry.

1 - *First you said the essential difference was the standby losses.
2 - Then you said how much you save depends on your usage patterns.
3 - And then you said losses from tank heaters are almost constant
regardless of how much you use.

For the record, I agree with 1 and 3.

For me, I look at my gas bill in summer, when all gas is used for is
the water heater and my outdoor gas grill. *It's about $17 or so a
month and that is with a std efficiency water heater. That includes
those standby losses and usage. *I could surely do better with a high
efficiency tank type. * *From that, I've concluded if I need a new
one, I'd go with a tank type higher efficiency one.

One simple test to settle the standby loss issue would be to read the
gas meter before going away for a few days to a week. *Before doing
that, draw enough water to fire it up. * Upon returning, see how much
gas it used.

- Hide quoted text -

- Show quoted text -- Hide quoted text -

- Show quoted text -

or tturn existing tank to vacation, come back a day or two later.

how warm is the water?

standby losses are overstated, in a heated basement standby loss helps
to keep your home warm in winter..- Hide quoted text -

- Show quoted text -

The heat goes up the chimney on the uninsulated center, Tank EF
ratings are 55-83. tankless are 82-96, 15-35% are standby losses.
Again you continously post wrong info.

On Nov 20, 1:05*pm, Joe wrote:
On Nov 20, 12:26*pm, " wrote:

snip
standby losses are overstated, in a heated basement standby loss helps
to keep your home warm in winter..

That's worth repeating for the logically impaired.

standby losses are overstated, in a heated basement standby loss helps
to keep your home warm in winter..

Joe

Oh give him a break, he has to make up a reason to justify his tank is
best.

wrote in message news:1966ef46-78f7-47b1-88a3- - Show
quoted text -

snip
standby losses are overstated, in a heated basement standby loss helps
to keep your home warm in winter..

Explain how that is helpful in Central TX?

g

Papa Pat wrote:

Are these water heaters worth the price to switch out from a
water tank?

Facts:

1) Natural gas prices have been very low the past few years, and there's
no indication that's going to change in the next few years. Anything
you spend to reduce natural gas usage will have a proportionately small
return on investment given low gas prices.

2) Conventional hot-water tanks are pretty efficient from a
standing-loss standpoint, and what little heat they do radiate can be
reduced by a relatively cheap external insulation blanket. On the other
hand, the radiant heat loss from the tank is captured inside your house,
the advantage of which is proportional to your northern geographic
location (or as a function of altitude).

3) heat loss from a conventional tank flue is minimal if you have a
power-vented system (when the fan isin't turning, it's acting like a
baffle preventing air flow through the flue). I suppose a
power-operated shutter could be added to completely close the flue and
prevent heat loss when the burner is not on.

4) efficiency of heat transfer is inversely proportional to the heat
gradient. The burner of an on-demand heater needs to put out 10's of
thousands, even 100+ thousand BTU in order to heat incoming water during
the water's short residency time inside the heater for the water to
reach conventional hot-water temperature (typically 140 to 160 f). The
more north you are, the colder your incoming water supply will be, and
the more capacity (in BTU) the burners will need to be to bring the
water up to the desired temperature. Exhaust heat loss from these units
is significant while they are operating, and during their off-cycle as
they cool down they can't dump much heat energy into the water because
there isin't much water stored in the unit.

Conversely, the burner of a conventional water tank is capable of much
less BTU heating, and the heat from the burner has more time to come
into contact with the internal tank surface and transfer it's heat into
the water. The exhaust gas temperature in the flue of a conventional
heater can be so cool as to require a small electric blower to properly
exhaust the gas out the flue. This is an indication that most of the
combustion heat is being transfered into the water and not being
exhausted out the chimney.

In other words, perhaps 50% of the combustion heat of an on-demand
heater is actually being transfered to the incoming cold water and the
other 50% is being lost in the exhaust, while 80% of the combustion heat
is absorbed by the water in a conventional tank. The difference is that
an on-demand heater is on perhaps 30 to 90 minutes per day, while a
conventional tank might be on for 4 hours a day. But remember that when
a conventional tank is on, it's burners are using a much smaller amount
of gas compared to the on-demand heater.

5) the efficient use of an on-demand heater is challenged by short
hot-water usage events. In most houses, the hot water lines are
minimally insulated and thus the water in them quickly drops to room
temperature. Anyone turning on a hot-water tap in an upstairs bathroom
will notice it take 10 to 30 seconds to actually get hot water. It
doesn't matter what type of heater you have (assuming the heater is in
the basement). A short hot-water use event (say, washing your hands)
will end up dumping a lot of waste heat out the exhaust when an
on-demand heater is signalled to turn on and then soon after turned off
to heat the water for that short-use event.

6) because of the very high heating capability (BTU capacity) of
on-demand heaters, the extreme thermal cycling of their internal
components will age the unit much faster than a conventional water
heater, and they do or will require more maintainence and repair vs a
conventional water heater (they have control devices, electronics, etc,
that are not present in conventional heaters, and as we all know -
electronics and HVAC equipment really don't tend to co-exist very well
for the long term).

7) on-demand heaters have electrical or electronic controls that require
a source of AC current. Thus they will not function during a power
failure. Anyone living in a northern climate that is subject to
sporadic winter power failures will not appreciate the lack of hot water
during extended outages.

Conclusion:

No home owner that has a working conventional gas water heater will ever
live long enough to recoup the savings from replacing his existing
working heater with an on-demand unit - and it's not a given that there
will actually be any measureable savings in gas use.

What has been observed is that the behavior of occupants change in terms
of how they use hot water when a conventional heater is replaced with an
on-demand heater, and that change usually results in less hot water use
(shorter showers, changes in shower heads, installation of low-flush
toilets, etc, insulating hot-water supply lines inside the house) so
it's not always clear where the savings come from and why.

Replacing an old / leaking conventional water heater is very easy for
most novice home owners / handymen, and at a cost of only a few hundred
dollars, the cost/reward ratio is still heavily in favor of replacing a
old conventional water heater with a new conventional unit.

You will get more bang-for-the-buck by

1) putting an insulating blanket around your existing or new
conventional water heater

2) insulating as much of the hot water supply lines inside your house as
you can reach

3) use a low-flow shower head

On-demand water heaters are basically a crock of **** designed to give
plumbing and HVAC companies a very lucrative new revenue stream.

Home Guy Said::::
On-demand water heaters are basically
a crock of **** designed to give
plumbing and HVAC companies a very
lucrative new revenue stream.

Well, nobody ever `splained it to me that way before.

Thank you... I read your whole soliloquy,
and I do understand what you wrote.

Especially that changing over to an on-demand water heater will never
return what you spent to install it...EVER.

You may get an argument from some in this group... but I thank you for
making me understand the big picture...

And thanks to all who took the time
to respond as well....

Pat in Denver

On Nov 20, 7:05*pm, Joe wrote:
On Nov 20, 12:26*pm, " wrote:

snip
standby losses are overstated, in a heated basement standby loss helps
to keep your home warm in winter..

That's worth repeating for the logically impaired.

standby losses are overstated, in a heated basement standby loss helps
to keep your home warm in winter..

Joe

Heating the basement is not an efficient way to heat your home.
Assuming the OP's water heater is in the basement. Which though common
in America is the most stupid place to put it.

On Nov 20, 8:14*pm, Home Guy wrote:
Papa Pat wrote:
Are these water heaters worth the price to switch out from a
water tank?

Facts:

1) Natural gas prices have been very low the past few years, and there's
no indication that's going to change in the next few years. *Anything
you spend to reduce natural gas usage will have a proportionately small
return on investment given low gas prices.

2) Conventional hot-water tanks are pretty efficient from a
standing-loss standpoint, and what little heat they do radiate can be
reduced by a relatively cheap external insulation blanket. *On the other
hand, the radiant heat loss from the tank is captured inside your house,
the advantage of which is proportional to your northern geographic
location (or as a function of altitude).

3) heat loss from a conventional tank flue is minimal if you have a
power-vented system (when the fan isin't turning, it's acting like a
baffle preventing air flow through the flue). *I suppose a
power-operated shutter could be added to completely close the flue and
prevent heat loss when the burner is not on.

4) efficiency of heat transfer is inversely proportional to the heat
gradient. *The burner of an on-demand heater needs to put out 10's of
thousands, even 100+ thousand BTU in order to heat incoming water during
the water's short residency time inside the heater for the water to
reach conventional hot-water temperature (typically 140 to 160 f). *The
more north you are, the colder your incoming water supply will be, and
the more capacity (in BTU) the burners will need to be to bring the
water up to the desired temperature. *Exhaust heat loss from these units
is significant while they are operating, and during their off-cycle as
they cool down they can't dump much heat energy into the water because
there isin't much water stored in the unit. *

Conversely, the burner of a conventional water tank is capable of much
less BTU heating, and the heat from the burner has more time to come
into contact with the internal tank surface and transfer it's heat into
the water. *The exhaust gas temperature in the flue of a conventional
heater can be so cool as to require a small electric blower to properly
exhaust the gas out the flue. *This is an indication that most of the
combustion heat is being transfered into the water and not being
exhausted out the chimney.

In other words, perhaps 50% of the combustion heat of an on-demand
heater is actually being transfered to the incoming cold water and the
other 50% is being lost in the exhaust, while 80% of the combustion heat
is absorbed by the water in a conventional tank. *The difference is that
an on-demand heater is on perhaps 30 to 90 minutes per day, while a
conventional tank might be on for 4 hours a day. *But remember that when
a conventional tank is on, it's burners are using a much smaller amount
of gas compared to the on-demand heater.

5) the efficient use of an on-demand heater is challenged by short
hot-water usage events. *In most houses, the hot water lines are
minimally insulated and thus the water in them quickly drops to room
temperature. *Anyone turning on a hot-water tap in an upstairs bathroom
will notice it take 10 to 30 seconds to actually get hot water. *It
doesn't matter what type of heater you have (assuming the heater is in
the basement). *A short hot-water use event (say, washing your hands)
will end up dumping a lot of waste heat out the exhaust when an
on-demand heater is signalled to turn on and then soon after turned off
to heat the water for that short-use event. *

6) because of the very high heating capability (BTU capacity) of
on-demand heaters, the extreme thermal cycling of their internal
components will age the unit much faster than a conventional water
heater, and they do or will require more maintainence and repair vs a
conventional water heater (they have control devices, electronics, etc,
that are not present in conventional heaters, and as we all know -
electronics and HVAC equipment really don't tend to co-exist very well
for the long term).

7) on-demand heaters have electrical or electronic controls that require
a source of AC current. *Thus they will not function during a power
failure. *Anyone living in a northern climate that is subject to
sporadic winter power failures will not appreciate the lack of hot water
during extended outages.

Conclusion:

No home owner that has a working conventional gas water heater will ever
live long enough to recoup the savings from replacing his existing
working heater with an on-demand unit - and it's not a given that there
will actually be any measureable savings in gas use.

What has been observed is that the behavior of occupants change in terms
of how they use hot water when a conventional heater is replaced with an
on-demand heater, and that change usually results in less hot water use
(shorter showers, changes in shower heads, installation of low-flush
toilets, etc, insulating hot-water supply lines inside the house) so
it's not always clear where the savings come from and why.

Replacing an old / leaking conventional water heater is very easy for
most novice home owners / handymen, and at a cost of only a few hundred
dollars, the cost/reward ratio is still heavily in favor of replacing a
old conventional water heater with a new conventional unit.

You will get more bang-for-the-buck by

1) putting an insulating blanket around your existing or new
conventional water heater

2) insulating as much of the hot water supply lines inside your house as
you can reach

3) use a low-flow shower head

On-demand water heaters are basically a crock of **** designed to give
plumbing and HVAC companies a very lucrative new revenue stream.

You are in cloud cuckoo land if you think the price of any fuel is
going to remain constant. It's true most American gas appliances of
all descriptions are the most inefficient in the world due to idleness
by manufacturerers and extreme conservatism by buyers.
However, European gas boilers are in excess of 100% in the best cases
and few are less than 95% efficient. You need tolook further afield.
This is the problem with American industry and why it is failing.

On Nov 21, 3:27*am, harry wrote:
On Nov 20, 8:14*pm, Home Guy wrote:





Papa Pat wrote:
Are these water heaters worth the price to switch out from a
water tank?

Facts:

1) Natural gas prices have been very low the past few years, and there's
no indication that's going to change in the next few years. *Anything
you spend to reduce natural gas usage will have a proportionately small
return on investment given low gas prices.

2) Conventional hot-water tanks are pretty efficient from a
standing-loss standpoint, and what little heat they do radiate can be
reduced by a relatively cheap external insulation blanket. *On the other
hand, the radiant heat loss from the tank is captured inside your house,
the advantage of which is proportional to your northern geographic
location (or as a function of altitude).

3) heat loss from a conventional tank flue is minimal if you have a
power-vented system (when the fan isin't turning, it's acting like a
baffle preventing air flow through the flue). *I suppose a
power-operated shutter could be added to completely close the flue and
prevent heat loss when the burner is not on.

4) efficiency of heat transfer is inversely proportional to the heat
gradient. *The burner of an on-demand heater needs to put out 10's of
thousands, even 100+ thousand BTU in order to heat incoming water during
the water's short residency time inside the heater for the water to
reach conventional hot-water temperature (typically 140 to 160 f). *The
more north you are, the colder your incoming water supply will be, and
the more capacity (in BTU) the burners will need to be to bring the
water up to the desired temperature. *Exhaust heat loss from these units
is significant while they are operating, and during their off-cycle as
they cool down they can't dump much heat energy into the water because
there isin't much water stored in the unit. *

Conversely, the burner of a conventional water tank is capable of much
less BTU heating, and the heat from the burner has more time to come
into contact with the internal tank surface and transfer it's heat into
the water. *The exhaust gas temperature in the flue of a conventional
heater can be so cool as to require a small electric blower to properly
exhaust the gas out the flue. *This is an indication that most of the
combustion heat is being transfered into the water and not being
exhausted out the chimney.

In other words, perhaps 50% of the combustion heat of an on-demand
heater is actually being transfered to the incoming cold water and the
other 50% is being lost in the exhaust, while 80% of the combustion heat
is absorbed by the water in a conventional tank. *The difference is that
an on-demand heater is on perhaps 30 to 90 minutes per day, while a
conventional tank might be on for 4 hours a day. *But remember that when
a conventional tank is on, it's burners are using a much smaller amount
of gas compared to the on-demand heater.

5) the efficient use of an on-demand heater is challenged by short
hot-water usage events. *In most houses, the hot water lines are
minimally insulated and thus the water in them quickly drops to room
temperature. *Anyone turning on a hot-water tap in an upstairs bathroom
will notice it take 10 to 30 seconds to actually get hot water. *It
doesn't matter what type of heater you have (assuming the heater is in
the basement). *A short hot-water use event (say, washing your hands)
will end up dumping a lot of waste heat out the exhaust when an
on-demand heater is signalled to turn on and then soon after turned off
to heat the water for that short-use event. *

6) because of the very high heating capability (BTU capacity) of
on-demand heaters, the extreme thermal cycling of their internal
components will age the unit much faster than a conventional water
heater, and they do or will require more maintainence and repair vs a
conventional water heater (they have control devices, electronics, etc,
that are not present in conventional heaters, and as we all know -
electronics and HVAC equipment really don't tend to co-exist very well
for the long term).

7) on-demand heaters have electrical or electronic controls that require
a source of AC current. *Thus they will not function during a power
failure. *Anyone living in a northern climate that is subject to
sporadic winter power failures will not appreciate the lack of hot water
during extended outages.

Conclusion:

No home owner that has a working conventional gas water heater will ever
live long enough to recoup the savings from replacing his existing
working heater with an on-demand unit - and it's not a given that there
will actually be any measureable savings in gas use.

What has been observed is that the behavior of occupants change in terms
of how they use hot water when a conventional heater is replaced with an
on-demand heater, and that change usually results in less hot water use
(shorter showers, changes in shower heads, installation of low-flush
toilets, etc, insulating hot-water supply lines inside the house) so
it's not always clear where the savings come from and why.

Replacing an old / leaking conventional water heater is very easy for
most novice home owners / handymen, and at a cost of only a few hundred
dollars, the cost/reward ratio is still heavily in favor of replacing a
old conventional water heater with a new conventional unit.

You will get more bang-for-the-buck by

1) putting an insulating blanket around your existing or new
conventional water heater

2) insulating as much of the hot water supply lines inside your house as
you can reach

3) use a low-flow shower head

On-demand water heaters are basically a crock of **** designed to give
plumbing and HVAC companies a very lucrative new revenue stream.

You are in cloud cuckoo land if you think the price of any fuel is
going to remain constant. *It's true most American gas appliances of
all descriptions are the most inefficient in the world due to idleness
by manufacturerers and extreme conservatism by buyers.
However, European gas boilers are in excess of 100% in the best cases
and few are less than 95% efficient. You need tolook further afield.
This is the problem with American industry and why it is failing.- Hide quoted text -

- Show quoted text -

You need to go back to school, what you state is nuts. No gas boiler
is over 100% efficient, no gas boiler is 100% efficient, the best is
around 98%. There is wasted heat out the chimney and there is the
loss. If you burn an unvented flame inside like a gas stove, that is
100%

On Nov 20, 3:14*pm, Home Guy wrote:
Papa Pat wrote:
Are these water heaters worth the price to switch out from a
water tank?

Facts:

1) Natural gas prices have been very low the past few years, and there's
no indication that's going to change in the next few years. *Anything
you spend to reduce natural gas usage will have a proportionately small
return on investment given low gas prices.

I don't know what you consider "very low", but here in the northeast
they sure don't meet my definition of that.



2) Conventional hot-water tanks are pretty efficient from a
standing-loss standpoint, and what little heat they do radiate can be
reduced by a relatively cheap external insulation blanket. *On the other
hand, the radiant heat loss from the tank is captured inside your house,
the advantage of which is proportional to your northern geographic
location (or as a function of altitude).

I'd say that depends a lot on whether the tank is high efficiency or
not. With a conventional flue system, as Ransley pointed out, most
of the lost heat goes up the flue, not into the house.




3) heat loss from a conventional tank flue is minimal if you have a
power-vented system (when the fan isin't turning, it's acting like a
baffle preventing air flow through the flue). *I suppose a
power-operated shutter could be added to completely close the flue and
prevent heat loss when the burner is not on.

4) efficiency of heat transfer is inversely proportional to the heat
gradient. *The burner of an on-demand heater needs to put out 10's of
thousands, even 100+ thousand BTU in order to heat incoming water during
the water's short residency time inside the heater for the water to
reach conventional hot-water temperature (typically 140 to 160 f). *The
more north you are, the colder your incoming water supply will be, and
the more capacity (in BTU) the burners will need to be to bring the
water up to the desired temperature. *Exhaust heat loss from these units
is significant while they are operating, and during their off-cycle as
they cool down they can't dump much heat energy into the water because
there isin't much water stored in the unit. *

There is however very likely enough water present in the tankless to
absorb most of the heat after the burner shuts off. Or else it would
boil, which apparently it does not.



Conversely, the burner of a conventional water tank is capable of much
less BTU heating, and the heat from the burner has more time to come
into contact with the internal tank surface and transfer it's heat into
the water. *The exhaust gas temperature in the flue of a conventional
heater can be so cool as to require a small electric blower to properly
exhaust the gas out the flue. *This is an indication that most of the
combustion heat is being transfered into the water and not being
exhausted out the chimney.

In other words, perhaps 50% of the combustion heat of an on-demand
heater is actually being transfered to the incoming cold water and the
other 50% is being lost in the exhaust, while 80% of the combustion heat
is absorbed by the water in a conventional tank. *The difference is that
an on-demand heater is on perhaps 30 to 90 minutes per day, while a
conventional tank might be on for 4 hours a day. *But remember that when
a conventional tank is on, it's burners are using a much smaller amount
of gas compared to the on-demand heater.

I'm sure most of us here would like to see any credible source to back
up this analysis. First, just about all of us agree that for the
typical residential usage, most of the energy in either type water
heater goes to heating water that is actually used, as opposed to
being lost. So, if tankless really only converted 50% of the gas used
into heated water, while a tank converted 80%, why would DOE and
similar organizations be recommending tankless to save energy?
Also, what are the efficiency rating numbers all about? Why don't we
see what you claim reflected in the efficiency ratings?




5) the efficient use of an on-demand heater is challenged by short
hot-water usage events. *In most houses, the hot water lines are
minimally insulated and thus the water in them quickly drops to room
temperature. *Anyone turning on a hot-water tap in an upstairs bathroom
will notice it take 10 to 30 seconds to actually get hot water. *It
doesn't matter what type of heater you have (assuming the heater is in
the basement). *A short hot-water use event (say, washing your hands)
will end up dumping a lot of waste heat out the exhaust when an
on-demand heater is signalled to turn on and then soon after turned off
to heat the water for that short-use event. *

6) because of the very high heating capability (BTU capacity) of
on-demand heaters, the extreme thermal cycling of their internal
components will age the unit much faster than a conventional water
heater, and they do or will require more maintainence and repair vs a
conventional water heater (they have control devices, electronics, etc,
that are not present in conventional heaters, and as we all know -
electronics and HVAC equipment really don't tend to co-exist very well
for the long term).

I'd like to see a credible source to back up this claim too. As for
their having "control devices, electronics, etc that are not present
in conventional heaters, while they may have different devices, it
hardly seems that they differ significantly in complexity from a
direct vent tank type water heater.



7) on-demand heaters have electrical or electronic controls that require
a source of AC current. *Thus they will not function during a power
failure. *Anyone living in a northern climate that is subject to
sporadic winter power failures will not appreciate the lack of hot water
during extended outages.

I believe there are some tankless that have battery power.



Conclusion:

No home owner that has a working conventional gas water heater will ever
live long enough to recoup the savings from replacing his existing
working heater with an on-demand unit - and it's not a given that there
will actually be any measureable savings in gas use.

Again, I'd like to see a source, besides your own opinion, that makes
this case. I think in most cases, it can take more than a few years,
perhaps even ten years. But it obviously depends on the particular
circumstances. Ransley bought his for $500 and installed it
himself. At the other extreme, you could have situations where it
requires increasing the gas service size, significant new piping runs,
etc. There are also cases where you can use a small tankless for
situations like a bathroom that is in a church and maybe used once a
week for a few hours. There a small tankless could be installed and
save the standby losses that you'd have for days when it's not used at
all. You can't just paint all the applications with one brush.






What has been observed is that the behavior of occupants change in terms
of how they use hot water when a conventional heater is replaced with an
on-demand heater, and that change usually results in less hot water use
(shorter showers, changes in shower heads, installation of low-flush
toilets, etc, insulating hot-water supply lines inside the house) so
it's not always clear where the savings come from and why.

Observed by whom? And how does that relate to the std tests that all
water heaters must undergo and show?



Replacing an old / leaking conventional water heater is very easy for
most novice home owners / handymen, and at a cost of only a few hundred
dollars, the cost/reward ratio is still heavily in favor of replacing a
old conventional water heater with a new conventional unit.

You will get more bang-for-the-buck by

1) putting an insulating blanket around your existing or new
conventional water heater

2) insulating as much of the hot water supply lines inside your house as
you can reach

3) use a low-flow shower head

On-demand water heaters are basically a crock of **** designed to give
plumbing and HVAC companies a very lucrative new revenue stream.


That about sums it up, eh?

Very possible that a lot of heat is lost up the flue pipe.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


"Joe" wrote in message
...
On Nov 20, 12:26 pm, " wrote:

snip

standby losses are overstated, in a heated basement standby loss
helps
to keep your home warm in winter..

That's worth repeating for the logically impaired.

[Very possible that a lot of heat is lost up the flue pipe. ]


standby losses are overstated, in a heated basement standby loss
helps
to keep your home warm in winter..

[Very possible that a lot of heat is lost up the flue pipe. ]

Joe

wrote:

For me, I look at my gas bill in summer, when all gas is used for is
the water heater and my outdoor gas grill. It's about $17 or so a
month and that is with a std efficiency water heater. That includes
those standby losses and usage. I could surely do better with a high
efficiency tank type. From that, I've concluded if I need a new
one, I'd go with a tank type higher efficiency one.


That $17 probably includes overhead.

I asked my gas company what my bill would be if I used no gas at all; their
answer: about $17.00. That amount helps pay for physically reading the
meter, mailing out a bill, recording the payment, etc. I can't begrudge them
the admistrative fee.

So, living in a converted duplex, I connected the gas lines from the two
sides of the building and cancelled the service to one side.

Saved $17 bucks a month.

On Nov 21, 7:46*am, ransley wrote:
On Nov 21, 3:27*am, harry wrote:





On Nov 20, 8:14*pm, Home Guy wrote:

Papa Pat wrote:
Are these water heaters worth the price to switch out from a
water tank?

Facts:

1) Natural gas prices have been very low the past few years, and there's
no indication that's going to change in the next few years. *Anything
you spend to reduce natural gas usage will have a proportionately small
return on investment given low gas prices.

2) Conventional hot-water tanks are pretty efficient from a
standing-loss standpoint, and what little heat they do radiate can be
reduced by a relatively cheap external insulation blanket. *On the other
hand, the radiant heat loss from the tank is captured inside your house,
the advantage of which is proportional to your northern geographic
location (or as a function of altitude).

3) heat loss from a conventional tank flue is minimal if you have a
power-vented system (when the fan isin't turning, it's acting like a
baffle preventing air flow through the flue). *I suppose a
power-operated shutter could be added to completely close the flue and
prevent heat loss when the burner is not on.

4) efficiency of heat transfer is inversely proportional to the heat
gradient. *The burner of an on-demand heater needs to put out 10's of
thousands, even 100+ thousand BTU in order to heat incoming water during
the water's short residency time inside the heater for the water to
reach conventional hot-water temperature (typically 140 to 160 f). *The
more north you are, the colder your incoming water supply will be, and
the more capacity (in BTU) the burners will need to be to bring the
water up to the desired temperature. *Exhaust heat loss from these units
is significant while they are operating, and during their off-cycle as
they cool down they can't dump much heat energy into the water because
there isin't much water stored in the unit. *

Conversely, the burner of a conventional water tank is capable of much
less BTU heating, and the heat from the burner has more time to come
into contact with the internal tank surface and transfer it's heat into
the water. *The exhaust gas temperature in the flue of a conventional
heater can be so cool as to require a small electric blower to properly
exhaust the gas out the flue. *This is an indication that most of the
combustion heat is being transfered into the water and not being
exhausted out the chimney.

In other words, perhaps 50% of the combustion heat of an on-demand
heater is actually being transfered to the incoming cold water and the
other 50% is being lost in the exhaust, while 80% of the combustion heat
is absorbed by the water in a conventional tank. *The difference is that
an on-demand heater is on perhaps 30 to 90 minutes per day, while a
conventional tank might be on for 4 hours a day. *But remember that when
a conventional tank is on, it's burners are using a much smaller amount
of gas compared to the on-demand heater.

5) the efficient use of an on-demand heater is challenged by short
hot-water usage events. *In most houses, the hot water lines are
minimally insulated and thus the water in them quickly drops to room
temperature. *Anyone turning on a hot-water tap in an upstairs bathroom
will notice it take 10 to 30 seconds to actually get hot water. *It
doesn't matter what type of heater you have (assuming the heater is in
the basement). *A short hot-water use event (say, washing your hands)
will end up dumping a lot of waste heat out the exhaust when an
on-demand heater is signalled to turn on and then soon after turned off
to heat the water for that short-use event. *

6) because of the very high heating capability (BTU capacity) of
on-demand heaters, the extreme thermal cycling of their internal
components will age the unit much faster than a conventional water
heater, and they do or will require more maintainence and repair vs a
conventional water heater (they have control devices, electronics, etc,
that are not present in conventional heaters, and as we all know -
electronics and HVAC equipment really don't tend to co-exist very well
for the long term).

7) on-demand heaters have electrical or electronic controls that require
a source of AC current. *Thus they will not function during a power
failure. *Anyone living in a northern climate that is subject to
sporadic winter power failures will not appreciate the lack of hot water
during extended outages.

Conclusion:

No home owner that has a working conventional gas water heater will ever
live long enough to recoup the savings from replacing his existing
working heater with an on-demand unit - and it's not a given that there
will actually be any measureable savings in gas use.

What has been observed is that the behavior of occupants change in terms
of how they use hot water when a conventional heater is replaced with an
on-demand heater, and that change usually results in less hot water use
(shorter showers, changes in shower heads, installation of low-flush
toilets, etc, insulating hot-water supply lines inside the house) so
it's not always clear where the savings come from and why.

Replacing an old / leaking conventional water heater is very easy for
most novice home owners / handymen, and at a cost of only a few hundred
dollars, the cost/reward ratio is still heavily in favor of replacing a
old conventional water heater with a new conventional unit.

You will get more bang-for-the-buck by

1) putting an insulating blanket around your existing or new
conventional water heater

2) insulating as much of the hot water supply lines inside your house as
you can reach

3) use a low-flow shower head

On-demand water heaters are basically a crock of **** designed to give
plumbing and HVAC companies a very lucrative new revenue stream.

You are in cloud cuckoo land if you think the price of any fuel is
going to remain constant. *It's true most American gas appliances of
all descriptions are the most inefficient in the world due to idleness
by manufacturerers and extreme conservatism by buyers.
However, European gas boilers are in excess of 100% in the best cases
and few are less than 95% efficient. You need tolook further afield.
This is the problem with American industry and why it is failing.- Hide quoted text -

- Show quoted text -

You need to go back to school, what you state is nuts.

It sure isn't the first time, either. They must have lost their way
in science in the UK since the days of Lord Kelvin and Sir Isaac
Newton.




No gas boiler
is over 100% efficient, no gas boiler is 100% efficient, the best is
around 98%. There is wasted heat out the chimney and there is the
loss. If you burn an unvented flame inside like a gas stove, that is
100%- Hide quoted text -

- Show quoted text -

"harry" wrote in message
...
On Nov 20, 7:05 pm, Joe wrote:
On Nov 20, 12:26 pm, " wrote:

snip
standby losses are overstated, in a heated basement standby loss helps
to keep your home warm in winter..

That's worth repeating for the logically impaired.

standby losses are overstated, in a heated basement standby loss helps
to keep your home warm in winter..

Joe

Heating the basement is not an efficient way to heat your home.
Assuming the OP's water heater is in the basement. Which though common
in America is the most stupid place to put it.

Sure, sure, Harry. Why not heat the attic? Oh, heat RISES. Or has England
managed to repeal the laws of thermodynamics?

Your anti-American screeds are getting pretty tiresome considering that if
you look at some of the world's perpetual trouble spots they're the result
of English imperialism. India/Pakistan, Northern Ireland, Africa and the
Middle East all have England's bloody handprints on them. Hell, if King
George acted a little less like King Kong, you might have even been able to
tap into the enormous wealth and resources of your American colony. But
instead you let a rag-tag bunch of militia men with muskets kick your sorry
Redcoat butts back across the pond to Britain, forcing you to look elsewhere
to build your empire.

As a result, we have the powder keg of India/Pakistan/Kashmir, the nexus of
world terrorism and one of the likely spots that for a nuclear war to begin.
Good job, mate.

Oh, before I forget, the colony that your Parliment tried to squeeze out of
existence with tax after tax still felt enough kinship with you to save your
sorry asses from Hitler in WWII. You'd be writing these posts in German if
not for the USA. That's probably what's stuck so deep in your craw, you
hate us because we saved you when all your British BS couldn't protect you
from the German war machine. My mother's cousin DIED in the merchant marine
bringing your country supplies so that you could survive, so in my view you
really should STFU about the US because I can go toe-to-toe with you. For
every bad thing the US has done, Britain has done far, far worse. In some
areas, like Prince Charles wishing he was Camilla's tampon, you're unmatched
in your lunacy.

--
Bobby G.

On Nov 21, 8:43*am, "Robert Green" wrote:
"harry" wrote in message

...
On Nov 20, 7:05 pm, Joe wrote:

On Nov 20, 12:26 pm, " wrote:

snip
standby losses are overstated, in a heated basement standby loss helps
to keep your home warm in winter..

That's worth repeating for the logically impaired.

standby losses are overstated, in a heated basement standby loss helps
to keep your home warm in winter..

Joe

Heating the basement is not an efficient way to heat your home.
Assuming the OP's water heater is in the basement. Which though common
in America is the most stupid place to put it.

Sure, sure, Harry. *Why not heat the attic? *Oh, heat RISES. *Or has England
managed to repeal the laws of thermodynamics?

Your anti-American screeds are getting pretty tiresome considering that if
you look at some of the world's perpetual trouble spots they're the result
of English imperialism. *India/Pakistan, Northern Ireland, Africa and the
Middle East all have England's bloody handprints on them. *Hell, if King
George acted a little less like King Kong, you might have even been able to
tap into the enormous wealth and resources of your American colony. *But
instead you let a rag-tag bunch of militia men with muskets kick your sorry
Redcoat butts back across the pond to Britain, forcing you to look elsewhere
to build your empire.

ROFLMAO! Well said my boy!






As a result, we have the powder keg of India/Pakistan/Kashmir, the nexus of
world terrorism and one of the likely spots that for a nuclear war to begin.
Good job, mate.

Oh, before I forget, the colony that your Parliment tried to squeeze out of
existence with tax after tax still felt enough kinship with you to save your
sorry asses from Hitler in WWII. *You'd be writing these posts in German if
not for the USA. *That's probably what's stuck so deep in your craw, you
hate us because we saved you when all your British BS couldn't protect you
from the German war machine. *My mother's cousin DIED in the merchant marine
bringing your country supplies so that you could survive, so in my view you
really should STFU about the US because I can go toe-to-toe with you. *For
every bad thing the US has done, Britain has done far, far worse. *In some
areas, like Prince Charles wishing he was Camilla's tampon, you're unmatched
in your lunacy.

--
Bobby G.

On Nov 20, 2:14*pm, Home Guy wrote:
Papa Pat wrote:
Are these water heaters worth the price to switch out from a
water tank?

Facts:

1) Natural gas prices have been very low the past few years, and there's
no indication that's going to change in the next few years. *Anything
you spend to reduce natural gas usage will have a proportionately small
return on investment given low gas prices.

2) Conventional hot-water tanks are pretty efficient from a
standing-loss standpoint, and what little heat they do radiate can be
reduced by a relatively cheap external insulation blanket. *On the other
hand, the radiant heat loss from the tank is captured inside your house,
the advantage of which is proportional to your northern geographic
location (or as a function of altitude).

3) heat loss from a conventional tank flue is minimal if you have a
power-vented system (when the fan isin't turning, it's acting like a
baffle preventing air flow through the flue). *I suppose a
power-operated shutter could be added to completely close the flue and
prevent heat loss when the burner is not on.

4) efficiency of heat transfer is inversely proportional to the heat
gradient. *The burner of an on-demand heater needs to put out 10's of
thousands, even 100+ thousand BTU in order to heat incoming water during
the water's short residency time inside the heater for the water to
reach conventional hot-water temperature (typically 140 to 160 f). *The
more north you are, the colder your incoming water supply will be, and
the more capacity (in BTU) the burners will need to be to bring the
water up to the desired temperature. *Exhaust heat loss from these units
is significant while they are operating, and during their off-cycle as
they cool down they can't dump much heat energy into the water because
there isin't much water stored in the unit. *

Conversely, the burner of a conventional water tank is capable of much
less BTU heating, and the heat from the burner has more time to come
into contact with the internal tank surface and transfer it's heat into
the water. *The exhaust gas temperature in the flue of a conventional
heater can be so cool as to require a small electric blower to properly
exhaust the gas out the flue. *This is an indication that most of the
combustion heat is being transfered into the water and not being
exhausted out the chimney.

In other words, perhaps 50% of the combustion heat of an on-demand
heater is actually being transfered to the incoming cold water and the
other 50% is being lost in the exhaust, while 80% of the combustion heat
is absorbed by the water in a conventional tank. *The difference is that
an on-demand heater is on perhaps 30 to 90 minutes per day, while a
conventional tank might be on for 4 hours a day. *But remember that when
a conventional tank is on, it's burners are using a much smaller amount
of gas compared to the on-demand heater.

5) the efficient use of an on-demand heater is challenged by short
hot-water usage events. *In most houses, the hot water lines are
minimally insulated and thus the water in them quickly drops to room
temperature. *Anyone turning on a hot-water tap in an upstairs bathroom
will notice it take 10 to 30 seconds to actually get hot water. *It
doesn't matter what type of heater you have (assuming the heater is in
the basement). *A short hot-water use event (say, washing your hands)
will end up dumping a lot of waste heat out the exhaust when an
on-demand heater is signalled to turn on and then soon after turned off
to heat the water for that short-use event. *

6) because of the very high heating capability (BTU capacity) of
on-demand heaters, the extreme thermal cycling of their internal
components will age the unit much faster than a conventional water
heater, and they do or will require more maintainence and repair vs a
conventional water heater (they have control devices, electronics, etc,
that are not present in conventional heaters, and as we all know -
electronics and HVAC equipment really don't tend to co-exist very well
for the long term).

7) on-demand heaters have electrical or electronic controls that require
a source of AC current. *Thus they will not function during a power
failure. *Anyone living in a northern climate that is subject to
sporadic winter power failures will not appreciate the lack of hot water
during extended outages.

Conclusion:

No home owner that has a working conventional gas water heater will ever
live long enough to recoup the savings from replacing his existing
working heater with an on-demand unit - and it's not a given that there
will actually be any measureable savings in gas use.

What has been observed is that the behavior of occupants change in terms
of how they use hot water when a conventional heater is replaced with an
on-demand heater, and that change usually results in less hot water use
(shorter showers, changes in shower heads, installation of low-flush
toilets, etc, insulating hot-water supply lines inside the house) so
it's not always clear where the savings come from and why.

Replacing an old / leaking conventional water heater is very easy for
most novice home owners / handymen, and at a cost of only a few hundred
dollars, the cost/reward ratio is still heavily in favor of replacing a
old conventional water heater with a new conventional unit.

You will get more bang-for-the-buck by

1) putting an insulating blanket around your existing or new
conventional water heater

2) insulating as much of the hot water supply lines inside your house as
you can reach

3) use a low-flow shower head


On-demand water heaters are basically a crock of **** designed to give
plumbing and HVAC companies a very lucrative new revenue stream.

What a bunch of bull**** you post this, must be hallerbs phony post..

1 Ng prices out pace inflation overthe long term, the trend is and
always has been up, only an idiot looks at the last year to determine
a long term price trend. So what you also say is why insulate, why
upgrade heating or windows, there just isnt the payback, dumb.

2. 90% of a tanks heat loss is up and out the chimney, you dont save
any thing, you dont heat the basement, you loose. "Tanks are pretty
efficient from a standby loss" learn about EF ratings , the majority
of tanks are 55-65 EF, a 65 EF tanks wastes nearly 35% in standby
loss. There is nothing efficient about that number

3 You are dreaming, or lying youself and everyone because you ignore
gov specified efficiency rating tests of domestic hot water heating
systems. The EF rating, that all tank and tankless systems are tested
by. Go look at EF ratings on tanks with power vent, most are 65 EF.
The worst tankless Ng is 82, the best go to go to 94 EF, no tank is
above 83EF. www.energystar.gov has all systems rated

4 Your statements are meaningless in determining what everyone wants
to know, and that is how efficient is a tank, Again you ignore EF
ratings, Energy Factor, a gov required standardised test that
determines the efficiency of domestic hot water systems. If you
learned and studied EFratings you wouldnt post all your lies. Or
maybe you would if you are a tank maker. www.energystar.gov has all
tank and tankless systems rated
Why dont you learn the truth about how unefficient a tank is and
research EF ratings. EF is how domestic hot water systems are rated,
itis the gov standard. www.energystar.gov has all tanks rated. By the
way I got a 5 year payback on a Ng tankless installed about 7 years
ago. You statements are mostly BS. www.energystar.gov has all tanks
and tankless rated.

5 So what, a cold pipe affects a tank the same way. The water isnt
heated and stored by Magic, evengy heats it.

6 My AO Smith condensing tank has more controls than does my tankless
by 3 x. And you compare the bottom of the barrel 55-60 EF tanks.
Bottom line, Ng tankless start at 92EF

7 Lie, get a Bosch with hydro generator.

Truth, tank EF ratings are 55-83EF with perhaps 99.8 % of units sold
in the 55-65 EF range. Ng tankless start at 82EF and go to 96 EF, Yes
you can save nearly 50% with tankless but a more likely amount is
15-20%, but instalation costs or a poor instalation can make it
worthless. They are not for everyone.

On Nov 21, 8:57*am, ransley wrote:
On Nov 20, 2:14*pm, Home Guy wrote:





Papa Pat wrote:
Are these water heaters worth the price to switch out from a
water tank?

Facts:

1) Natural gas prices have been very low the past few years, and there's
no indication that's going to change in the next few years. *Anything
you spend to reduce natural gas usage will have a proportionately small
return on investment given low gas prices.

2) Conventional hot-water tanks are pretty efficient from a
standing-loss standpoint, and what little heat they do radiate can be
reduced by a relatively cheap external insulation blanket. *On the other
hand, the radiant heat loss from the tank is captured inside your house,
the advantage of which is proportional to your northern geographic
location (or as a function of altitude).

3) heat loss from a conventional tank flue is minimal if you have a
power-vented system (when the fan isin't turning, it's acting like a
baffle preventing air flow through the flue). *I suppose a
power-operated shutter could be added to completely close the flue and
prevent heat loss when the burner is not on.

4) efficiency of heat transfer is inversely proportional to the heat
gradient. *The burner of an on-demand heater needs to put out 10's of
thousands, even 100+ thousand BTU in order to heat incoming water during
the water's short residency time inside the heater for the water to
reach conventional hot-water temperature (typically 140 to 160 f). *The
more north you are, the colder your incoming water supply will be, and
the more capacity (in BTU) the burners will need to be to bring the
water up to the desired temperature. *Exhaust heat loss from these units
is significant while they are operating, and during their off-cycle as
they cool down they can't dump much heat energy into the water because
there isin't much water stored in the unit. *

Conversely, the burner of a conventional water tank is capable of much
less BTU heating, and the heat from the burner has more time to come
into contact with the internal tank surface and transfer it's heat into
the water. *The exhaust gas temperature in the flue of a conventional
heater can be so cool as to require a small electric blower to properly
exhaust the gas out the flue. *This is an indication that most of the
combustion heat is being transfered into the water and not being
exhausted out the chimney.

In other words, perhaps 50% of the combustion heat of an on-demand
heater is actually being transfered to the incoming cold water and the
other 50% is being lost in the exhaust, while 80% of the combustion heat
is absorbed by the water in a conventional tank. *The difference is that
an on-demand heater is on perhaps 30 to 90 minutes per day, while a
conventional tank might be on for 4 hours a day. *But remember that when
a conventional tank is on, it's burners are using a much smaller amount
of gas compared to the on-demand heater.

5) the efficient use of an on-demand heater is challenged by short
hot-water usage events. *In most houses, the hot water lines are
minimally insulated and thus the water in them quickly drops to room
temperature. *Anyone turning on a hot-water tap in an upstairs bathroom
will notice it take 10 to 30 seconds to actually get hot water. *It
doesn't matter what type of heater you have (assuming the heater is in
the basement). *A short hot-water use event (say, washing your hands)
will end up dumping a lot of waste heat out the exhaust when an
on-demand heater is signalled to turn on and then soon after turned off
to heat the water for that short-use event. *

6) because of the very high heating capability (BTU capacity) of
on-demand heaters, the extreme thermal cycling of their internal
components will age the unit much faster than a conventional water
heater, and they do or will require more maintainence and repair vs a
conventional water heater (they have control devices, electronics, etc,
that are not present in conventional heaters, and as we all know -
electronics and HVAC equipment really don't tend to co-exist very well
for the long term).

7) on-demand heaters have electrical or electronic controls that require
a source of AC current. *Thus they will not function during a power
failure. *Anyone living in a northern climate that is subject to
sporadic winter power failures will not appreciate the lack of hot water
during extended outages.

Conclusion:

No home owner that has a working conventional gas water heater will ever
live long enough to recoup the savings from replacing his existing
working heater with an on-demand unit - and it's not a given that there
will actually be any measureable savings in gas use.

What has been observed is that the behavior of occupants change in terms
of how they use hot water when a conventional heater is replaced with an
on-demand heater, and that change usually results in less hot water use
(shorter showers, changes in shower heads, installation of low-flush
toilets, etc, insulating hot-water supply lines inside the house) so
it's not always clear where the savings come from and why.

Replacing an old / leaking conventional water heater is very easy for
most novice home owners / handymen, and at a cost of only a few hundred
dollars, the cost/reward ratio is still heavily in favor of replacing a
old conventional water heater with a new conventional unit.

You will get more bang-for-the-buck by

1) putting an insulating blanket around your existing or new
conventional water heater

2) insulating as much of the hot water supply lines inside your house as
you can reach

3) use a low-flow shower head
On-demand water heaters are basically a crock of **** designed to give
plumbing and HVAC companies a very lucrative new revenue stream.

What a bunch of bull**** you post this, must be hallerbs phony post..

1 Ng prices out pace inflation overthe long term, the trend is and
always has been up, only an idiot looks at the last year to determine
a long term price trend. So what you also say is why insulate, why
upgrade heating or windows, there just isnt the payback, dumb.

2. 90% of a tanks heat loss is up and out the chimney, you dont save
any thing, you dont heat the basement, you loose. *"Tanks are pretty
efficient from a standby loss" *learn about EF ratings , the majority
of tanks are 55-65 EF, a 65 EF tanks wastes nearly 35% in standby
loss. There is nothing efficient about that number

3 *You are dreaming, or lying youself and everyone because you ignore
gov specified efficiency rating tests of domestic hot water heating
systems. The EF rating, that all tank and tankless systems are tested
by. Go look at EF ratings on *tanks with power vent, most are 65 EF.
The worst tankless Ng is 82, the best go to go to 94 EF, no tank is
above 83EF.www.energystar.govhas all systems rated

4 Your statements are meaningless in determining what everyone wants
to know, and that is how efficient is a tank, Again you ignore EF
ratings, Energy Factor, a gov required standardised test that
determines the efficiency of domestic hot water systems. If you
learned and studied EFratings *you wouldnt post all your lies. Or
maybe you would if you are a tank maker.www.energystar.govhas all
tank and tankless systems rated
Why dont you learn the truth about how unefficient a tank is and
research EF ratings. EF is how domestic hot water systems are rated,
itis the gov standard. *www.energystar.govhas all tanks rated. By the
way I got a 5 year payback on a Ng tankless installed about 7 years
ago. You statements are mostly BS.www.energystar.govhas all tanks
and tankless rated.

5 So what, a cold pipe affects a tank the same way. The water isnt
heated and stored by Magic, evengy heats it.

6 *My AO Smith condensing tank has more controls than does my tankless
by 3 x. And you compare the bottom of the barrel 55-60 EF tanks.
Bottom line, Ng tankless start at 92EF

7 Lie, get a Bosch with hydro generator.

*Truth, tank EF ratings are 55-83EF with perhaps 99.8 % of units sold
in the 55-65 EF range. Ng tankless start at 82EF and go to 96 EF, Yes
you can save nearly 50% with tankless but a more likely amount is
15-20%, but instalation costs or a poor instalation can make it
worthless. They are not for everyone.- Hide quoted text -

- Show quoted text -

if a tankless has a power vent, that requires power line voltage to
operate.

no power no hot watewr at all.

On Nov 21, 9:34*am, " wrote:
On Nov 21, 8:57*am, ransley wrote:





On Nov 20, 2:14*pm, Home Guy wrote:

Papa Pat wrote:
Are these water heaters worth the price to switch out from a
water tank?

Facts:

1) Natural gas prices have been very low the past few years, and there's
no indication that's going to change in the next few years. *Anything
you spend to reduce natural gas usage will have a proportionately small
return on investment given low gas prices.

2) Conventional hot-water tanks are pretty efficient from a
standing-loss standpoint, and what little heat they do radiate can be
reduced by a relatively cheap external insulation blanket. *On the other
hand, the radiant heat loss from the tank is captured inside your house,
the advantage of which is proportional to your northern geographic
location (or as a function of altitude).

3) heat loss from a conventional tank flue is minimal if you have a
power-vented system (when the fan isin't turning, it's acting like a
baffle preventing air flow through the flue). *I suppose a
power-operated shutter could be added to completely close the flue and
prevent heat loss when the burner is not on.

4) efficiency of heat transfer is inversely proportional to the heat
gradient. *The burner of an on-demand heater needs to put out 10's of
thousands, even 100+ thousand BTU in order to heat incoming water during
the water's short residency time inside the heater for the water to
reach conventional hot-water temperature (typically 140 to 160 f). *The
more north you are, the colder your incoming water supply will be, and
the more capacity (in BTU) the burners will need to be to bring the
water up to the desired temperature. *Exhaust heat loss from these units
is significant while they are operating, and during their off-cycle as
they cool down they can't dump much heat energy into the water because
there isin't much water stored in the unit. *

Conversely, the burner of a conventional water tank is capable of much
less BTU heating, and the heat from the burner has more time to come
into contact with the internal tank surface and transfer it's heat into
the water. *The exhaust gas temperature in the flue of a conventional
heater can be so cool as to require a small electric blower to properly
exhaust the gas out the flue. *This is an indication that most of the
combustion heat is being transfered into the water and not being
exhausted out the chimney.

In other words, perhaps 50% of the combustion heat of an on-demand
heater is actually being transfered to the incoming cold water and the
other 50% is being lost in the exhaust, while 80% of the combustion heat
is absorbed by the water in a conventional tank. *The difference is that
an on-demand heater is on perhaps 30 to 90 minutes per day, while a
conventional tank might be on for 4 hours a day. *But remember that when
a conventional tank is on, it's burners are using a much smaller amount
of gas compared to the on-demand heater.

5) the efficient use of an on-demand heater is challenged by short
hot-water usage events. *In most houses, the hot water lines are
minimally insulated and thus the water in them quickly drops to room
temperature. *Anyone turning on a hot-water tap in an upstairs bathroom
will notice it take 10 to 30 seconds to actually get hot water. *It
doesn't matter what type of heater you have (assuming the heater is in
the basement). *A short hot-water use event (say, washing your hands)
will end up dumping a lot of waste heat out the exhaust when an
on-demand heater is signalled to turn on and then soon after turned off
to heat the water for that short-use event. *

6) because of the very high heating capability (BTU capacity) of
on-demand heaters, the extreme thermal cycling of their internal
components will age the unit much faster than a conventional water
heater, and they do or will require more maintainence and repair vs a
conventional water heater (they have control devices, electronics, etc,
that are not present in conventional heaters, and as we all know -
electronics and HVAC equipment really don't tend to co-exist very well
for the long term).

7) on-demand heaters have electrical or electronic controls that require
a source of AC current. *Thus they will not function during a power
failure. *Anyone living in a northern climate that is subject to
sporadic winter power failures will not appreciate the lack of hot water
during extended outages.

Conclusion:

No home owner that has a working conventional gas water heater will ever
live long enough to recoup the savings from replacing his existing
working heater with an on-demand unit - and it's not a given that there
will actually be any measureable savings in gas use.

What has been observed is that the behavior of occupants change in terms
of how they use hot water when a conventional heater is replaced with an
on-demand heater, and that change usually results in less hot water use
(shorter showers, changes in shower heads, installation of low-flush
toilets, etc, insulating hot-water supply lines inside the house) so
it's not always clear where the savings come from and why.

Replacing an old / leaking conventional water heater is very easy for
most novice home owners / handymen, and at a cost of only a few hundred
dollars, the cost/reward ratio is still heavily in favor of replacing a
old conventional water heater with a new conventional unit.

You will get more bang-for-the-buck by

1) putting an insulating blanket around your existing or new
conventional water heater

2) insulating as much of the hot water supply lines inside your house as
you can reach

3) use a low-flow shower head
On-demand water heaters are basically a crock of **** designed to give
plumbing and HVAC companies a very lucrative new revenue stream.

What a bunch of bull**** you post this, must be hallerbs phony post..

1 Ng prices out pace inflation overthe long term, the trend is and
always has been up, only an idiot looks at the last year to determine
a long term price trend. So what you also say is why insulate, why
upgrade heating or windows, there just isnt the payback, dumb.

2. 90% of a tanks heat loss is up and out the chimney, you dont save
any thing, you dont heat the basement, you loose. *"Tanks are pretty
efficient from a standby loss" *learn about EF ratings , the majority
of tanks are 55-65 EF, a 65 EF tanks wastes nearly 35% in standby
loss. There is nothing efficient about that number

3 *You are dreaming, or lying youself and everyone because you ignore
gov specified efficiency rating tests of domestic hot water heating
systems. The EF rating, that all tank and tankless systems are tested
by. Go look at EF ratings on *tanks with power vent, most are 65 EF.
The worst tankless Ng is 82, the best go to go to 94 EF, no tank is
above 83EF.www.energystar.govhasall systems rated

4 Your statements are meaningless in determining what everyone wants
to know, and that is how efficient is a tank, Again you ignore EF
ratings, Energy Factor, a gov required standardised test that
determines the efficiency of domestic hot water systems. If you
learned and studied EFratings *you wouldnt post all your lies. Or
maybe you would if you are a tank maker.www.energystar.govhasall
tank and tankless systems rated
Why dont you learn the truth about how unefficient a tank is and
research EF ratings. EF is how domestic hot water systems are rated,
itis the gov standard. *www.energystar.govhasall tanks rated. By the
way I got a 5 year payback on a Ng tankless installed about 7 years
ago. You statements are mostly BS.www.energystar.govhasall tanks
and tankless rated.

5 So what, a cold pipe affects a tank the same way. The water isnt
heated and stored by Magic, evengy heats it.

6 *My AO Smith condensing tank has more controls than does my tankless
by 3 x. And you compare the bottom of the barrel 55-60 EF tanks.
Bottom line, Ng tankless start at 92EF

7 Lie, get a Bosch with hydro generator.

*Truth, tank EF ratings are 55-83EF with perhaps 99.8 % of units sold
in the 55-65 EF range. Ng tankless start at 82EF and go to 96 EF, Yes
you can save nearly 50% with tankless but a more likely amount is
15-20%, but instalation costs or a poor instalation can make it
worthless. They are not for everyone.- Hide quoted text -

- Show quoted text -

if a tankless has a power vent, that requires power line voltage to
operate.

no power no hot watewr at all.- Hide quoted text -

- Show quoted text -

Mine has no blower, it can vent up a chimney, people have been doing
that a few hundred years.

wrote in message
...

stuff snipped

if a tankless has a power vent, that requires power line voltage to
operate.

no power no hot watewr at all.

One winter, when power was off for three days, we heated the bedroom with
water bottles filled from the gas tank water heater w/pilot light. A little
wasteful of water, but more than offset in hotel costs we didn't have to
pay. Sometimes newer isn't really better and in some ways, even a little
bit worse.

--
Bobby G.

On Nov 21, 12:46*pm, ransley wrote:
On Nov 21, 3:27*am, harry wrote:





On Nov 20, 8:14*pm, Home Guy wrote:

Papa Pat wrote:
Are these water heaters worth the price to switch out from a
water tank?

Facts:

1) Natural gas prices have been very low the past few years, and there's
no indication that's going to change in the next few years. *Anything
you spend to reduce natural gas usage will have a proportionately small
return on investment given low gas prices.

2) Conventional hot-water tanks are pretty efficient from a
standing-loss standpoint, and what little heat they do radiate can be
reduced by a relatively cheap external insulation blanket. *On the other
hand, the radiant heat loss from the tank is captured inside your house,
the advantage of which is proportional to your northern geographic
location (or as a function of altitude).

3) heat loss from a conventional tank flue is minimal if you have a
power-vented system (when the fan isin't turning, it's acting like a
baffle preventing air flow through the flue). *I suppose a
power-operated shutter could be added to completely close the flue and
prevent heat loss when the burner is not on.

4) efficiency of heat transfer is inversely proportional to the heat
gradient. *The burner of an on-demand heater needs to put out 10's of
thousands, even 100+ thousand BTU in order to heat incoming water during
the water's short residency time inside the heater for the water to
reach conventional hot-water temperature (typically 140 to 160 f). *The
more north you are, the colder your incoming water supply will be, and
the more capacity (in BTU) the burners will need to be to bring the
water up to the desired temperature. *Exhaust heat loss from these units
is significant while they are operating, and during their off-cycle as
they cool down they can't dump much heat energy into the water because
there isin't much water stored in the unit. *

Conversely, the burner of a conventional water tank is capable of much
less BTU heating, and the heat from the burner has more time to come
into contact with the internal tank surface and transfer it's heat into
the water. *The exhaust gas temperature in the flue of a conventional
heater can be so cool as to require a small electric blower to properly
exhaust the gas out the flue. *This is an indication that most of the
combustion heat is being transfered into the water and not being
exhausted out the chimney.

In other words, perhaps 50% of the combustion heat of an on-demand
heater is actually being transfered to the incoming cold water and the
other 50% is being lost in the exhaust, while 80% of the combustion heat
is absorbed by the water in a conventional tank. *The difference is that
an on-demand heater is on perhaps 30 to 90 minutes per day, while a
conventional tank might be on for 4 hours a day. *But remember that when
a conventional tank is on, it's burners are using a much smaller amount
of gas compared to the on-demand heater.

5) the efficient use of an on-demand heater is challenged by short
hot-water usage events. *In most houses, the hot water lines are
minimally insulated and thus the water in them quickly drops to room
temperature. *Anyone turning on a hot-water tap in an upstairs bathroom
will notice it take 10 to 30 seconds to actually get hot water. *It
doesn't matter what type of heater you have (assuming the heater is in
the basement). *A short hot-water use event (say, washing your hands)
will end up dumping a lot of waste heat out the exhaust when an
on-demand heater is signalled to turn on and then soon after turned off
to heat the water for that short-use event. *

6) because of the very high heating capability (BTU capacity) of
on-demand heaters, the extreme thermal cycling of their internal
components will age the unit much faster than a conventional water
heater, and they do or will require more maintainence and repair vs a
conventional water heater (they have control devices, electronics, etc,
that are not present in conventional heaters, and as we all know -
electronics and HVAC equipment really don't tend to co-exist very well
for the long term).

7) on-demand heaters have electrical or electronic controls that require
a source of AC current. *Thus they will not function during a power
failure. *Anyone living in a northern climate that is subject to
sporadic winter power failures will not appreciate the lack of hot water
during extended outages.

Conclusion:

No home owner that has a working conventional gas water heater will ever
live long enough to recoup the savings from replacing his existing
working heater with an on-demand unit - and it's not a given that there
will actually be any measureable savings in gas use.

What has been observed is that the behavior of occupants change in terms
of how they use hot water when a conventional heater is replaced with an
on-demand heater, and that change usually results in less hot water use
(shorter showers, changes in shower heads, installation of low-flush
toilets, etc, insulating hot-water supply lines inside the house) so
it's not always clear where the savings come from and why.

Replacing an old / leaking conventional water heater is very easy for
most novice home owners / handymen, and at a cost of only a few hundred
dollars, the cost/reward ratio is still heavily in favor of replacing a
old conventional water heater with a new conventional unit.

You will get more bang-for-the-buck by

1) putting an insulating blanket around your existing or new
conventional water heater

2) insulating as much of the hot water supply lines inside your house as
you can reach

3) use a low-flow shower head

On-demand water heaters are basically a crock of **** designed to give
plumbing and HVAC companies a very lucrative new revenue stream.

You are in cloud cuckoo land if you think the price of any fuel is
going to remain constant. *It's true most American gas appliances of
all descriptions are the most inefficient in the world due to idleness
by manufacturerers and extreme conservatism by buyers.
However, European gas boilers are in excess of 100% in the best cases
and few are less than 95% efficient. You need tolook further afield.
This is the problem with American industry and why it is failing.- Hide quoted text -

- Show quoted text -

You need to go back to school, what you state is nuts. No gas boiler
is over 100% efficient, no gas boiler is 100% efficient, the best is
around 98%. There is wasted heat out the chimney and there is the
loss. If you burn an unvented flame inside like a gas stove, that is
100%- Hide quoted text -

- Show quoted text -

How can a gas boiler exceed 100% efficiency? Simply by condensing
the water out of combustion products. this is "extra" heat not
available in non-condensing boilers.
This is mostly latent heat (or heat of vaporisation in your parlance I
believe).
However to achieve this efficiency the heating system has to be
designed for low temperatures on the incoming water. However domestic
hot water is perfect with cold water entering heat exchanger.

On Nov 21, 1:43*pm, "Robert Green" wrote:
"harry" wrote in message

...
On Nov 20, 7:05 pm, Joe wrote:

On Nov 20, 12:26 pm, " wrote:

snip
standby losses are overstated, in a heated basement standby loss helps
to keep your home warm in winter..

That's worth repeating for the logically impaired.

standby losses are overstated, in a heated basement standby loss helps
to keep your home warm in winter..

Joe

Heating the basement is not an efficient way to heat your home.
Assuming the OP's water heater is in the basement. Which though common
in America is the most stupid place to put it.

Sure, sure, Harry. *Why not heat the attic? *Oh, heat RISES. *Or has England
managed to repeal the laws of thermodynamics?

Your anti-American screeds are getting pretty tiresome considering that if
you look at some of the world's perpetual trouble spots they're the result
of English imperialism. *India/Pakistan, Northern Ireland, Africa and the
Middle East all have England's bloody handprints on them. *Hell, if King
George acted a little less like King Kong, you might have even been able to
tap into the enormous wealth and resources of your American colony. *But
instead you let a rag-tag bunch of militia men with muskets kick your sorry
Redcoat butts back across the pond to Britain, forcing you to look elsewhere
to build your empire.

As a result, we have the powder keg of India/Pakistan/Kashmir, the nexus of
world terrorism and one of the likely spots that for a nuclear war to begin.
Good job, mate.

Oh, before I forget, the colony that your Parliment tried to squeeze out of
existence with tax after tax still felt enough kinship with you to save your
sorry asses from Hitler in WWII. *You'd be writing these posts in German if
not for the USA. *That's probably what's stuck so deep in your craw, you
hate us because we saved you when all your British BS couldn't protect you
from the German war machine. *My mother's cousin DIED in the merchant marine
bringing your country supplies so that you could survive, so in my view you
really should STFU about the US because I can go toe-to-toe with you. *For
every bad thing the US has done, Britain has done far, far worse. *In some
areas, like Prince Charles wishing he was Camilla's tampon, you're unmatched
in your lunacy.

--
Bobby G.

Oho. There is no more imperialistic state than the USA, an entire
country/continent stolen from it's inhabitants who were systematically
ethnically cleansed, lied to and murdered. Then we need only travel
South. Mexico invaded and large chunks of it's territory stolen.
Nicaragua, Honduras, Salvador, Panama, Colombia, Chile, Cuba Costa
Rica, Philipines, Hawaii. All stolen, attempted to be stolen or
interfered with costong thousands of lives..
And lets be clear. Germany and Japan declared war on you. You came
running to us for help when that happened.
There is no such thing as liberty in America. You are enslaved to your
bankers and wealthy war-mongers, who need perpetual war to enrich
themselves. You illegally kidnap, torture and kill foriegn
nationals. You are responsible for the deaths of tens of thousands in
the Middle East. Your current wars are not about liberty or
democracy, they are to defend Israel and it's fascist zionist land
grabbers and bankers.
So don't lecture me about moral values, the USA has sunk to the levels
of Nazi Germany, with the activities of Bush and Cheney. Self admitted
to breaking the Hague conventions and international law.

On Sun, 21 Nov 2010 01:20:03 -0800 (PST), harry wrote:

On Nov 20, 7:05*pm, Joe wrote:
On Nov 20, 12:26*pm, " wrote:

snip
standby losses are overstated, in a heated basement standby loss helps
to keep your home warm in winter..

That's worth repeating for the logically impaired.

standby losses are overstated, in a heated basement standby loss helps
to keep your home warm in winter..

Joe

Heating the basement is not an efficient way to heat your home.
Assuming the OP's water heater is in the basement. Which though common
in America is the most stupid place to put it.

That's good to know. I don't have a basement but I do have an attic and
that's where my water heater is. ;-)

On Nov 21, 10:58*am, harry wrote:
On Nov 21, 12:46*pm, ransley wrote:





On Nov 21, 3:27*am, harry wrote:

On Nov 20, 8:14*pm, Home Guy wrote:

Papa Pat wrote:
Are these water heaters worth the price to switch out from a
water tank?

Facts:

1) Natural gas prices have been very low the past few years, and there's
no indication that's going to change in the next few years. *Anything
you spend to reduce natural gas usage will have a proportionately small
return on investment given low gas prices.

2) Conventional hot-water tanks are pretty efficient from a
standing-loss standpoint, and what little heat they do radiate can be
reduced by a relatively cheap external insulation blanket. *On the other
hand, the radiant heat loss from the tank is captured inside your house,
the advantage of which is proportional to your northern geographic
location (or as a function of altitude).

3) heat loss from a conventional tank flue is minimal if you have a
power-vented system (when the fan isin't turning, it's acting like a
baffle preventing air flow through the flue). *I suppose a
power-operated shutter could be added to completely close the flue and
prevent heat loss when the burner is not on.

4) efficiency of heat transfer is inversely proportional to the heat
gradient. *The burner of an on-demand heater needs to put out 10's of
thousands, even 100+ thousand BTU in order to heat incoming water during
the water's short residency time inside the heater for the water to
reach conventional hot-water temperature (typically 140 to 160 f). *The
more north you are, the colder your incoming water supply will be, and
the more capacity (in BTU) the burners will need to be to bring the
water up to the desired temperature. *Exhaust heat loss from these units
is significant while they are operating, and during their off-cycle as
they cool down they can't dump much heat energy into the water because
there isin't much water stored in the unit. *

Conversely, the burner of a conventional water tank is capable of much
less BTU heating, and the heat from the burner has more time to come
into contact with the internal tank surface and transfer it's heat into
the water. *The exhaust gas temperature in the flue of a conventional
heater can be so cool as to require a small electric blower to properly
exhaust the gas out the flue. *This is an indication that most of the
combustion heat is being transfered into the water and not being
exhausted out the chimney.

In other words, perhaps 50% of the combustion heat of an on-demand
heater is actually being transfered to the incoming cold water and the
other 50% is being lost in the exhaust, while 80% of the combustion heat
is absorbed by the water in a conventional tank. *The difference is that
an on-demand heater is on perhaps 30 to 90 minutes per day, while a
conventional tank might be on for 4 hours a day. *But remember that when
a conventional tank is on, it's burners are using a much smaller amount
of gas compared to the on-demand heater.

5) the efficient use of an on-demand heater is challenged by short
hot-water usage events. *In most houses, the hot water lines are
minimally insulated and thus the water in them quickly drops to room
temperature. *Anyone turning on a hot-water tap in an upstairs bathroom
will notice it take 10 to 30 seconds to actually get hot water. *It
doesn't matter what type of heater you have (assuming the heater is in
the basement). *A short hot-water use event (say, washing your hands)
will end up dumping a lot of waste heat out the exhaust when an
on-demand heater is signalled to turn on and then soon after turned off
to heat the water for that short-use event. *

6) because of the very high heating capability (BTU capacity) of
on-demand heaters, the extreme thermal cycling of their internal
components will age the unit much faster than a conventional water
heater, and they do or will require more maintainence and repair vs a
conventional water heater (they have control devices, electronics, etc,
that are not present in conventional heaters, and as we all know -
electronics and HVAC equipment really don't tend to co-exist very well
for the long term).

7) on-demand heaters have electrical or electronic controls that require
a source of AC current. *Thus they will not function during a power
failure. *Anyone living in a northern climate that is subject to
sporadic winter power failures will not appreciate the lack of hot water
during extended outages.

Conclusion:

No home owner that has a working conventional gas water heater will ever
live long enough to recoup the savings from replacing his existing
working heater with an on-demand unit - and it's not a given that there
will actually be any measureable savings in gas use.

What has been observed is that the behavior of occupants change in terms
of how they use hot water when a conventional heater is replaced with an
on-demand heater, and that change usually results in less hot water use
(shorter showers, changes in shower heads, installation of low-flush
toilets, etc, insulating hot-water supply lines inside the house) so
it's not always clear where the savings come from and why.

Replacing an old / leaking conventional water heater is very easy for
most novice home owners / handymen, and at a cost of only a few hundred
dollars, the cost/reward ratio is still heavily in favor of replacing a
old conventional water heater with a new conventional unit.

You will get more bang-for-the-buck by

1) putting an insulating blanket around your existing or new
conventional water heater

2) insulating as much of the hot water supply lines inside your house as
you can reach

3) use a low-flow shower head

On-demand water heaters are basically a crock of **** designed to give
plumbing and HVAC companies a very lucrative new revenue stream.

You are in cloud cuckoo land if you think the price of any fuel is
going to remain constant. *It's true most American gas appliances of
all descriptions are the most inefficient in the world due to idleness
by manufacturerers and extreme conservatism by buyers.
However, European gas boilers are in excess of 100% in the best cases
and few are less than 95% efficient. You need tolook further afield.
This is the problem with American industry and why it is failing.- Hide quoted text -

- Show quoted text -

You need to go back to school, what you state is nuts. No gas boiler
is over 100% efficient, no gas boiler is 100% efficient, the best is
around 98%. There is wasted heat out the chimney and there is the
loss. If you burn an unvented flame inside like a gas stove, that is
100%- Hide quoted text -

- Show quoted text -

* How can a gas boiler exceed 100% efficiency? *Simply by condensing
the water out of combustion products. this is "extra" heat not
available in non-condensing boilers.
This is mostly latent heat (or heat of vaporisation in your parlance I
believe).
However to achieve this efficiency the heating system has to be
designed for low temperatures on the incoming water. However domestic
hot water is perfect with cold water entering heat exchanger.- Hide quoted text -

- Show quoted text -

There you are wrong, a Btu is a Btu and this is 6th grade stuff, you
cant get back more btus then you put in. Its a fundamental part of
energy. If you could get more out than you put in your reasoning
would lead to perpetual motion of other energy forms. Look at our AFUE
ratings for furnaces, we correctly rate that condensing furnaces and
boilers start at about 92% and go to 98%, its tested and proven by
science you dont get more than you put in burning gas for condensing
units. You still waste energy with condensing units, it goes out the
chimney. I have a condensing furnace, boiler and condensing AO Smith
water tank, None of mine are rated over 96% and nothing sold is rated
over 100%, even 99% is likely a lie as heat is wasted out the
chimney . If your point was correct running a stove would be over 100%
efficient, but it takes energy to condense water.

On Sun, 21 Nov 2010 09:18:27 -0800 (PST), harry wrote:

On Nov 21, 1:43*pm, "Robert Green" wrote:
"harry" wrote in message

...
On Nov 20, 7:05 pm, Joe wrote:

On Nov 20, 12:26 pm, " wrote:

snip
standby losses are overstated, in a heated basement standby loss helps
to keep your home warm in winter..

That's worth repeating for the logically impaired.

standby losses are overstated, in a heated basement standby loss helps
to keep your home warm in winter..

Joe

Heating the basement is not an efficient way to heat your home.
Assuming the OP's water heater is in the basement. Which though common
in America is the most stupid place to put it.

Sure, sure, Harry. *Why not heat the attic? *Oh, heat RISES. *Or has England
managed to repeal the laws of thermodynamics?

Your anti-American screeds are getting pretty tiresome considering that if
you look at some of the world's perpetual trouble spots they're the result
of English imperialism. *India/Pakistan, Northern Ireland, Africa and the
Middle East all have England's bloody handprints on them. *Hell, if King
George acted a little less like King Kong, you might have even been able to
tap into the enormous wealth and resources of your American colony. *But
instead you let a rag-tag bunch of militia men with muskets kick your sorry
Redcoat butts back across the pond to Britain, forcing you to look elsewhere
to build your empire.

As a result, we have the powder keg of India/Pakistan/Kashmir, the nexus of
world terrorism and one of the likely spots that for a nuclear war to begin.
Good job, mate.

Oh, before I forget, the colony that your Parliment tried to squeeze out of
existence with tax after tax still felt enough kinship with you to save your
sorry asses from Hitler in WWII. *You'd be writing these posts in German if
not for the USA. *That's probably what's stuck so deep in your craw, you
hate us because we saved you when all your British BS couldn't protect you
from the German war machine. *My mother's cousin DIED in the merchant marine
bringing your country supplies so that you could survive, so in my view you
really should STFU about the US because I can go toe-to-toe with you. *For
every bad thing the US has done, Britain has done far, far worse. *In some
areas, like Prince Charles wishing he was Camilla's tampon, you're unmatched
in your lunacy.

--
Bobby G.

Oho. There is no more imperialistic state than the USA, an entire
country/continent stolen from it's inhabitants who were systematically
ethnically cleansed, lied to and murdered.

Yeah, England had nothing to do with that, nor would ever think of doing such
in *any* part of the world. Hypocrite!

Then we need only travel
South. Mexico invaded and large chunks of it's territory stolen.
Nicaragua, Honduras, Salvador, Panama, Colombia, Chile, Cuba Costa
Rica, Philipines, Hawaii. All stolen, attempted to be stolen or
interfered with costong thousands of lives..

Clueless.

And lets be clear. Germany and Japan declared war on you. You came
running to us for help when that happened.

Lies. You were no position to "help" anyone. You couldn't even help the rest
of Europe.

There is no such thing as liberty in America.

There is no absolute liberty anywhere, moron.

You are enslaved to your
bankers and wealthy war-mongers, who need perpetual war to enrich
themselves. You illegally kidnap, torture and kill foriegn
nationals.

Wrong.

You are responsible for the deaths of tens of thousands in
the Middle East.

Not enough.

Your current wars are not about liberty or
democracy, they are to defend Israel and it's fascist zionist land
grabbers and bankers.

Clueless bigot.

So don't lecture me about moral values, the USA has sunk to the levels
of Nazi Germany, with the activities of Bush and Cheney. Self admitted
to breaking the Hague conventions and international law.

Hypocrite.

In 2003 when my power was out, four days. A hot shower or hot tub bath
really made life a lot more comfortable. Glad my WH wasn't reliant on
electricity for hot watewr.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


wrote in message
...


if a tankless has a power vent, that requires power line voltage to
operate.

no power no hot watewr at all.

One caller to a "news and information" radio station.
Called, and mentioned he'd hooked a garden hose to
his cellar sink. Ran the hose through the house,
snaked back and forth. Ending up at a drain. The
slow flow of hot water warmed the house. Now
days, Wirsbo does this intentionally, using plastic
tubing.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


"Robert Green" wrote in message
...

One winter, when power was off for three days, we heated
the bedroom with water bottles filled from the gas tank water
heater w/pilot light. A little wasteful of water, but more than
offset in hotel costs we didn't have to pay. Sometimes newer
isn't really better and in some ways, even a little bit worse.

--
Bobby G.

Dear Harry,
Please take the time to research "90% efficiency furnaces". You
may be surprised to find out that... well, I won't spoil the surprise.
Your ignornace is showing.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


"harry" wrote in message
...

You need to go back to school, what you state is nuts. No gas boiler
is over 100% efficient, no gas boiler is 100% efficient, the best is
around 98%. There is wasted heat out the chimney and there is the
loss. If you burn an unvented flame inside like a gas stove, that is
100%- Hide quoted text -

- Show quoted text -

How can a gas boiler exceed 100% efficiency? Simply by condensing
the water out of combustion products. this is "extra" heat not
available in non-condensing boilers.
This is mostly latent heat (or heat of vaporisation in your parlance I
believe).
However to achieve this efficiency the heating system has to be
designed for low temperatures on the incoming water. However domestic
hot water is perfect with cold water entering heat exchanger.

On Nov 21, 1:04*pm, ransley wrote:
On Nov 21, 10:58*am, harry wrote:





On Nov 21, 12:46*pm, ransley wrote:

On Nov 21, 3:27*am, harry wrote:

On Nov 20, 8:14*pm, Home Guy wrote:

Papa Pat wrote:
Are these water heaters worth the price to switch out from a
water tank?

Facts:

1) Natural gas prices have been very low the past few years, and there's
no indication that's going to change in the next few years. *Anything
you spend to reduce natural gas usage will have a proportionately small
return on investment given low gas prices.

2) Conventional hot-water tanks are pretty efficient from a
standing-loss standpoint, and what little heat they do radiate can be
reduced by a relatively cheap external insulation blanket. *On the other
hand, the radiant heat loss from the tank is captured inside your house,
the advantage of which is proportional to your northern geographic
location (or as a function of altitude).

3) heat loss from a conventional tank flue is minimal if you have a
power-vented system (when the fan isin't turning, it's acting like a
baffle preventing air flow through the flue). *I suppose a
power-operated shutter could be added to completely close the flue and
prevent heat loss when the burner is not on.

4) efficiency of heat transfer is inversely proportional to the heat
gradient. *The burner of an on-demand heater needs to put out 10's of
thousands, even 100+ thousand BTU in order to heat incoming water during
the water's short residency time inside the heater for the water to
reach conventional hot-water temperature (typically 140 to 160 f).. *The
more north you are, the colder your incoming water supply will be, and
the more capacity (in BTU) the burners will need to be to bring the
water up to the desired temperature. *Exhaust heat loss from these units
is significant while they are operating, and during their off-cycle as
they cool down they can't dump much heat energy into the water because
there isin't much water stored in the unit. *

Conversely, the burner of a conventional water tank is capable of much
less BTU heating, and the heat from the burner has more time to come
into contact with the internal tank surface and transfer it's heat into
the water. *The exhaust gas temperature in the flue of a conventional
heater can be so cool as to require a small electric blower to properly
exhaust the gas out the flue. *This is an indication that most of the
combustion heat is being transfered into the water and not being
exhausted out the chimney.

In other words, perhaps 50% of the combustion heat of an on-demand
heater is actually being transfered to the incoming cold water and the
other 50% is being lost in the exhaust, while 80% of the combustion heat
is absorbed by the water in a conventional tank. *The difference is that
an on-demand heater is on perhaps 30 to 90 minutes per day, while a
conventional tank might be on for 4 hours a day. *But remember that when
a conventional tank is on, it's burners are using a much smaller amount
of gas compared to the on-demand heater.

5) the efficient use of an on-demand heater is challenged by short
hot-water usage events. *In most houses, the hot water lines are
minimally insulated and thus the water in them quickly drops to room
temperature. *Anyone turning on a hot-water tap in an upstairs bathroom
will notice it take 10 to 30 seconds to actually get hot water. *It
doesn't matter what type of heater you have (assuming the heater is in
the basement). *A short hot-water use event (say, washing your hands)
will end up dumping a lot of waste heat out the exhaust when an
on-demand heater is signalled to turn on and then soon after turned off
to heat the water for that short-use event. *

6) because of the very high heating capability (BTU capacity) of
on-demand heaters, the extreme thermal cycling of their internal
components will age the unit much faster than a conventional water
heater, and they do or will require more maintainence and repair vs a
conventional water heater (they have control devices, electronics, etc,
that are not present in conventional heaters, and as we all know -
electronics and HVAC equipment really don't tend to co-exist very well
for the long term).

7) on-demand heaters have electrical or electronic controls that require
a source of AC current. *Thus they will not function during a power
failure. *Anyone living in a northern climate that is subject to
sporadic winter power failures will not appreciate the lack of hot water
during extended outages.

Conclusion:

No home owner that has a working conventional gas water heater will ever
live long enough to recoup the savings from replacing his existing
working heater with an on-demand unit - and it's not a given that there
will actually be any measureable savings in gas use.

What has been observed is that the behavior of occupants change in terms
of how they use hot water when a conventional heater is replaced with an
on-demand heater, and that change usually results in less hot water use
(shorter showers, changes in shower heads, installation of low-flush
toilets, etc, insulating hot-water supply lines inside the house) so
it's not always clear where the savings come from and why.

Replacing an old / leaking conventional water heater is very easy for
most novice home owners / handymen, and at a cost of only a few hundred
dollars, the cost/reward ratio is still heavily in favor of replacing a
old conventional water heater with a new conventional unit.

You will get more bang-for-the-buck by

1) putting an insulating blanket around your existing or new
conventional water heater

2) insulating as much of the hot water supply lines inside your house as
you can reach

3) use a low-flow shower head

On-demand water heaters are basically a crock of **** designed to give
plumbing and HVAC companies a very lucrative new revenue stream.

You are in cloud cuckoo land if you think the price of any fuel is
going to remain constant. *It's true most American gas appliances of
all descriptions are the most inefficient in the world due to idleness
by manufacturerers and extreme conservatism by buyers.
However, European gas boilers are in excess of 100% in the best cases
and few are less than 95% efficient. You need tolook further afield..
This is the problem with American industry and why it is failing.- Hide quoted text -

- Show quoted text -

You need to go back to school, what you state is nuts. No gas boiler
is over 100% efficient, no gas boiler is 100% efficient, the best is
around 98%. There is wasted heat out the chimney and there is the
loss. If you burn an unvented flame inside like a gas stove, that is
100%- Hide quoted text -

- Show quoted text -

* How can a gas boiler exceed 100% efficiency? *Simply by condensing
the water out of combustion products. this is "extra" heat not
available in non-condensing boilers.
This is mostly latent heat (or heat of vaporisation in your parlance I
believe).
However to achieve this efficiency the heating system has to be
designed for low temperatures on the incoming water. However domestic
hot water is perfect with cold water entering heat exchanger.- Hide quoted text -

- Show quoted text -

There you are wrong, a Btu is a Btu and this is 6th grade stuff, you
cant get back more btus then you put in. Its a fundamental part of
energy. If you could get more out than you put in your reasoning
would lead to perpetual motion of other energy forms. Look at our AFUE
ratings for furnaces, we correctly rate that condensing furnaces and
boilers start at about 92% and go to 98%, its tested and proven by
science you dont get more than you put in burning gas for condensing
units. You still waste energy with condensing units, it goes out the
chimney. I have a condensing furnace, boiler and condensing AO Smith
water tank, None of mine are rated over 96% and nothing sold is rated
over 100%, even 99% is likely a lie as heat is wasted out the
chimney . If your point was correct running a stove would be over 100%
efficient, but it takes energy to condense water.- Hide quoted text -

- Show quoted text -

condensing furnaces and water heaters dont use a chimey they exhaust
thru PVC pipe thru the wall at a very low but slightly warm
temperature.

condensing is more efficent than tankless, if you doubt this just hold
your hand in a standard tankless exhaust get the burn cream ready
you will need it

On Nov 21, 5:37*pm, " wrote:
On Nov 21, 1:04*pm, ransley wrote:





On Nov 21, 10:58*am, harry wrote:

On Nov 21, 12:46*pm, ransley wrote:

On Nov 21, 3:27*am, harry wrote:

On Nov 20, 8:14*pm, Home Guy wrote:

Papa Pat wrote:
Are these water heaters worth the price to switch out from a
water tank?

Facts:

1) Natural gas prices have been very low the past few years, and there's
no indication that's going to change in the next few years. *Anything
you spend to reduce natural gas usage will have a proportionately small
return on investment given low gas prices.

2) Conventional hot-water tanks are pretty efficient from a
standing-loss standpoint, and what little heat they do radiate can be
reduced by a relatively cheap external insulation blanket. *On the other
hand, the radiant heat loss from the tank is captured inside your house,
the advantage of which is proportional to your northern geographic
location (or as a function of altitude).

3) heat loss from a conventional tank flue is minimal if you have a
power-vented system (when the fan isin't turning, it's acting like a
baffle preventing air flow through the flue). *I suppose a
power-operated shutter could be added to completely close the flue and
prevent heat loss when the burner is not on.

4) efficiency of heat transfer is inversely proportional to the heat
gradient. *The burner of an on-demand heater needs to put out 10's of
thousands, even 100+ thousand BTU in order to heat incoming water during
the water's short residency time inside the heater for the water to
reach conventional hot-water temperature (typically 140 to 160 f). *The
more north you are, the colder your incoming water supply will be, and
the more capacity (in BTU) the burners will need to be to bring the
water up to the desired temperature. *Exhaust heat loss from these units
is significant while they are operating, and during their off-cycle as
they cool down they can't dump much heat energy into the water because
there isin't much water stored in the unit. *

Conversely, the burner of a conventional water tank is capable of much
less BTU heating, and the heat from the burner has more time to come
into contact with the internal tank surface and transfer it's heat into
the water. *The exhaust gas temperature in the flue of a conventional
heater can be so cool as to require a small electric blower to properly
exhaust the gas out the flue. *This is an indication that most of the
combustion heat is being transfered into the water and not being
exhausted out the chimney.

In other words, perhaps 50% of the combustion heat of an on-demand
heater is actually being transfered to the incoming cold water and the
other 50% is being lost in the exhaust, while 80% of the combustion heat
is absorbed by the water in a conventional tank. *The difference is that
an on-demand heater is on perhaps 30 to 90 minutes per day, while a
conventional tank might be on for 4 hours a day. *But remember that when
a conventional tank is on, it's burners are using a much smaller amount
of gas compared to the on-demand heater.

5) the efficient use of an on-demand heater is challenged by short
hot-water usage events. *In most houses, the hot water lines are
minimally insulated and thus the water in them quickly drops to room
temperature. *Anyone turning on a hot-water tap in an upstairs bathroom
will notice it take 10 to 30 seconds to actually get hot water. *It
doesn't matter what type of heater you have (assuming the heater is in
the basement). *A short hot-water use event (say, washing your hands)
will end up dumping a lot of waste heat out the exhaust when an
on-demand heater is signalled to turn on and then soon after turned off
to heat the water for that short-use event. *

6) because of the very high heating capability (BTU capacity) of
on-demand heaters, the extreme thermal cycling of their internal
components will age the unit much faster than a conventional water
heater, and they do or will require more maintainence and repair vs a
conventional water heater (they have control devices, electronics, etc,
that are not present in conventional heaters, and as we all know -
electronics and HVAC equipment really don't tend to co-exist very well
for the long term).

7) on-demand heaters have electrical or electronic controls that require
a source of AC current. *Thus they will not function during a power
failure. *Anyone living in a northern climate that is subject to
sporadic winter power failures will not appreciate the lack of hot water
during extended outages.

Conclusion:

No home owner that has a working conventional gas water heater will ever
live long enough to recoup the savings from replacing his existing
working heater with an on-demand unit - and it's not a given that there
will actually be any measureable savings in gas use.

What has been observed is that the behavior of occupants change in terms
of how they use hot water when a conventional heater is replaced with an
on-demand heater, and that change usually results in less hot water use
(shorter showers, changes in shower heads, installation of low-flush
toilets, etc, insulating hot-water supply lines inside the house) so
it's not always clear where the savings come from and why.

Replacing an old / leaking conventional water heater is very easy for
most novice home owners / handymen, and at a cost of only a few hundred
dollars, the cost/reward ratio is still heavily in favor of replacing a
old conventional water heater with a new conventional unit.

You will get more bang-for-the-buck by

1) putting an insulating blanket around your existing or new
conventional water heater

2) insulating as much of the hot water supply lines inside your house as
you can reach

3) use a low-flow shower head

On-demand water heaters are basically a crock of **** designed to give
plumbing and HVAC companies a very lucrative new revenue stream..

You are in cloud cuckoo land if you think the price of any fuel is
going to remain constant. *It's true most American gas appliances of
all descriptions are the most inefficient in the world due to idleness
by manufacturerers and extreme conservatism by buyers.
However, European gas boilers are in excess of 100% in the best cases
and few are less than 95% efficient. You need tolook further afield.
This is the problem with American industry and why it is failing.- Hide quoted text -

- Show quoted text -

You need to go back to school, what you state is nuts. No gas boiler
is over 100% efficient, no gas boiler is 100% efficient, the best is
around 98%. There is wasted heat out the chimney and there is the
loss. If you burn an unvented flame inside like a gas stove, that is
100%- Hide quoted text -

- Show quoted text -

* How can a gas boiler exceed 100% efficiency? *Simply by condensing
the water out of combustion products. this is "extra" heat not
available in non-condensing boilers.
This is mostly latent heat (or heat of vaporisation in your parlance I
believe).
However to achieve this efficiency the heating system has to be
designed for low temperatures on the incoming water. However domestic
hot water is perfect with cold water entering heat exchanger.- Hide quoted text -

- Show quoted text -

There you are wrong, a Btu is a Btu and this is 6th grade stuff, you
cant get back more btus then you put in. Its a fundamental part of
energy. If you could get more out than you put in your reasoning
would lead to perpetual motion of other energy forms. Look at our AFUE
ratings for furnaces, we correctly rate that condensing furnaces and
boilers start at about 92% and go to 98%, its tested and proven by
science you dont get more than you put in burning gas for condensing
units. You still waste energy with condensing units, it goes out the
chimney. I have a condensing furnace, boiler and condensing AO Smith
water tank, None of mine are rated over 96% and nothing sold is rated
over 100%, even 99% is likely a lie as heat is wasted out the
chimney . If your point was correct running a stove would be over 100%
efficient, but it takes energy to condense water.- Hide quoted text -

- Show quoted text -

condensing furnaces and water heaters dont use a chimey they exhaust
thru PVC pipe thru the wall at a very low but slightly warm
temperature.

condensing is more efficent than tankless, if you doubt this just hold
your hand in a standard *tankless exhaust get the burn cream ready
you will need it- Hide quoted text -

- Show quoted text -

I didnt state anything different on condensing systems. There are
tankless condensing, how do you think a 94 EF rating is acheived, 94EF
the highest rating of any water heating system. One of the highest
rated tanks I know of is my AO Smith Cyclone a condensing commercial
unit. It is in no way more efficient than my cheapy bosch non
condensing tankless, Read the EF number on AO, if you can find it,
because they hide the sad truth.

I didnt state anything different on condensing systems. There are
tankless condensing, how do you think a 94 EF rating is acheived, 94EF
the highest rating of any water heating system. One of the highest
rated tanks I know of is my AO Smith Cyclone a condensing commercial
unit. It is in no way more efficient than my cheapy bosch non
condensing tankless, Read the EF number on AO, if you can find it,
because they hide the sad truth.


one of the AO Smith condensing water heaters get the fed energy
credit.

thats a wonderful tax break

"Stormin Mormon" wrote in message
...
In 2003 when my power was out, four days. A hot shower or hot tub bath
really made life a lot more comfortable. Glad my WH wasn't reliant on
electricity for hot watewr.

Amen. I specifically opted for a pilot light unit when I got the most
recent unit just so I would be able to "rough it" if the power failed for a
long enough time. It's just like camping, but instead of lighting a fire, I
kept filling and dumping a bunch of 5 gallon containers. Kept the bedroom
toasty and that's all that mattered. I might even consider a hose next
time like you mentioned in your other post. Jackassing 5 gallon containers
was a little tiresome.

--
Bobby G.

On Nov 21, 6:04*pm, ransley wrote:
On Nov 21, 10:58*am, harry wrote:





On Nov 21, 12:46*pm, ransley wrote:

On Nov 21, 3:27*am, harry wrote:

On Nov 20, 8:14*pm, Home Guy wrote:

Papa Pat wrote:
Are these water heaters worth the price to switch out from a
water tank?

Facts:

1) Natural gas prices have been very low the past few years, and there's
no indication that's going to change in the next few years. *Anything
you spend to reduce natural gas usage will have a proportionately small
return on investment given low gas prices.

2) Conventional hot-water tanks are pretty efficient from a
standing-loss standpoint, and what little heat they do radiate can be
reduced by a relatively cheap external insulation blanket. *On the other
hand, the radiant heat loss from the tank is captured inside your house,
the advantage of which is proportional to your northern geographic
location (or as a function of altitude).

3) heat loss from a conventional tank flue is minimal if you have a
power-vented system (when the fan isin't turning, it's acting like a
baffle preventing air flow through the flue). *I suppose a
power-operated shutter could be added to completely close the flue and
prevent heat loss when the burner is not on.

4) efficiency of heat transfer is inversely proportional to the heat
gradient. *The burner of an on-demand heater needs to put out 10's of
thousands, even 100+ thousand BTU in order to heat incoming water during
the water's short residency time inside the heater for the water to
reach conventional hot-water temperature (typically 140 to 160 f).. *The
more north you are, the colder your incoming water supply will be, and
the more capacity (in BTU) the burners will need to be to bring the
water up to the desired temperature. *Exhaust heat loss from these units
is significant while they are operating, and during their off-cycle as
they cool down they can't dump much heat energy into the water because
there isin't much water stored in the unit. *

Conversely, the burner of a conventional water tank is capable of much
less BTU heating, and the heat from the burner has more time to come
into contact with the internal tank surface and transfer it's heat into
the water. *The exhaust gas temperature in the flue of a conventional
heater can be so cool as to require a small electric blower to properly
exhaust the gas out the flue. *This is an indication that most of the
combustion heat is being transfered into the water and not being
exhausted out the chimney.

In other words, perhaps 50% of the combustion heat of an on-demand
heater is actually being transfered to the incoming cold water and the
other 50% is being lost in the exhaust, while 80% of the combustion heat
is absorbed by the water in a conventional tank. *The difference is that
an on-demand heater is on perhaps 30 to 90 minutes per day, while a
conventional tank might be on for 4 hours a day. *But remember that when
a conventional tank is on, it's burners are using a much smaller amount
of gas compared to the on-demand heater.

5) the efficient use of an on-demand heater is challenged by short
hot-water usage events. *In most houses, the hot water lines are
minimally insulated and thus the water in them quickly drops to room
temperature. *Anyone turning on a hot-water tap in an upstairs bathroom
will notice it take 10 to 30 seconds to actually get hot water. *It
doesn't matter what type of heater you have (assuming the heater is in
the basement). *A short hot-water use event (say, washing your hands)
will end up dumping a lot of waste heat out the exhaust when an
on-demand heater is signalled to turn on and then soon after turned off
to heat the water for that short-use event. *

6) because of the very high heating capability (BTU capacity) of
on-demand heaters, the extreme thermal cycling of their internal
components will age the unit much faster than a conventional water
heater, and they do or will require more maintainence and repair vs a
conventional water heater (they have control devices, electronics, etc,
that are not present in conventional heaters, and as we all know -
electronics and HVAC equipment really don't tend to co-exist very well
for the long term).

7) on-demand heaters have electrical or electronic controls that require
a source of AC current. *Thus they will not function during a power
failure. *Anyone living in a northern climate that is subject to
sporadic winter power failures will not appreciate the lack of hot water
during extended outages.

Conclusion:

No home owner that has a working conventional gas water heater will ever
live long enough to recoup the savings from replacing his existing
working heater with an on-demand unit - and it's not a given that there
will actually be any measureable savings in gas use.

What has been observed is that the behavior of occupants change in terms
of how they use hot water when a conventional heater is replaced with an
on-demand heater, and that change usually results in less hot water use
(shorter showers, changes in shower heads, installation of low-flush
toilets, etc, insulating hot-water supply lines inside the house) so
it's not always clear where the savings come from and why.

Replacing an old / leaking conventional water heater is very easy for
most novice home owners / handymen, and at a cost of only a few hundred
dollars, the cost/reward ratio is still heavily in favor of replacing a
old conventional water heater with a new conventional unit.

You will get more bang-for-the-buck by

1) putting an insulating blanket around your existing or new
conventional water heater

2) insulating as much of the hot water supply lines inside your house as
you can reach

3) use a low-flow shower head

On-demand water heaters are basically a crock of **** designed to give
plumbing and HVAC companies a very lucrative new revenue stream.

You are in cloud cuckoo land if you think the price of any fuel is
going to remain constant. *It's true most American gas appliances of
all descriptions are the most inefficient in the world due to idleness
by manufacturerers and extreme conservatism by buyers.
However, European gas boilers are in excess of 100% in the best cases
and few are less than 95% efficient. You need tolook further afield..
This is the problem with American industry and why it is failing.- Hide quoted text -

- Show quoted text -

You need to go back to school, what you state is nuts. No gas boiler
is over 100% efficient, no gas boiler is 100% efficient, the best is
around 98%. There is wasted heat out the chimney and there is the
loss. If you burn an unvented flame inside like a gas stove, that is
100%- Hide quoted text -

- Show quoted text -

* How can a gas boiler exceed 100% efficiency? *Simply by condensing
the water out of combustion products. this is "extra" heat not
available in non-condensing boilers.
This is mostly latent heat (or heat of vaporisation in your parlance I
believe).
However to achieve this efficiency the heating system has to be
designed for low temperatures on the incoming water. However domestic
hot water is perfect with cold water entering heat exchanger.- Hide quoted text -

- Show quoted text -

There you are wrong, a Btu is a Btu and this is 6th grade stuff, you
cant get back more btus then you put in. Its a fundamental part of
energy. If you could get more out than you put in your reasoning
would lead to perpetual motion of other energy forms. Look at our AFUE
ratings for furnaces, we correctly rate that condensing furnaces and
boilers start at about 92% and go to 98%, its tested and proven by
science you dont get more than you put in burning gas for condensing
units. You still waste energy with condensing units, it goes out the
chimney. I have a condensing furnace, boiler and condensing AO Smith
water tank, None of mine are rated over 96% and nothing sold is rated
over 100%, even 99% is likely a lie as heat is wasted out the
chimney . If your point was correct running a stove would be over 100%
efficient, but it takes energy to condense water.- Hide quoted text -

- Show quoted text -

I know what a British Thermal Unit is thankyou.
To condense water you EXTRACT energy. (This how we get more than 100%)
To evaporate water you add energy.
Try to keep up.

On Nov 21, 11:37*pm, " wrote:
On Nov 21, 1:04*pm, ransley wrote:





On Nov 21, 10:58*am, harry wrote:

On Nov 21, 12:46*pm, ransley wrote:

On Nov 21, 3:27*am, harry wrote:

On Nov 20, 8:14*pm, Home Guy wrote:

Papa Pat wrote:
Are these water heaters worth the price to switch out from a
water tank?

Facts:

1) Natural gas prices have been very low the past few years, and there's
no indication that's going to change in the next few years. *Anything
you spend to reduce natural gas usage will have a proportionately small
return on investment given low gas prices.

2) Conventional hot-water tanks are pretty efficient from a
standing-loss standpoint, and what little heat they do radiate can be
reduced by a relatively cheap external insulation blanket. *On the other
hand, the radiant heat loss from the tank is captured inside your house,
the advantage of which is proportional to your northern geographic
location (or as a function of altitude).

3) heat loss from a conventional tank flue is minimal if you have a
power-vented system (when the fan isin't turning, it's acting like a
baffle preventing air flow through the flue). *I suppose a
power-operated shutter could be added to completely close the flue and
prevent heat loss when the burner is not on.

4) efficiency of heat transfer is inversely proportional to the heat
gradient. *The burner of an on-demand heater needs to put out 10's of
thousands, even 100+ thousand BTU in order to heat incoming water during
the water's short residency time inside the heater for the water to
reach conventional hot-water temperature (typically 140 to 160 f). *The
more north you are, the colder your incoming water supply will be, and
the more capacity (in BTU) the burners will need to be to bring the
water up to the desired temperature. *Exhaust heat loss from these units
is significant while they are operating, and during their off-cycle as
they cool down they can't dump much heat energy into the water because
there isin't much water stored in the unit. *

Conversely, the burner of a conventional water tank is capable of much
less BTU heating, and the heat from the burner has more time to come
into contact with the internal tank surface and transfer it's heat into
the water. *The exhaust gas temperature in the flue of a conventional
heater can be so cool as to require a small electric blower to properly
exhaust the gas out the flue. *This is an indication that most of the
combustion heat is being transfered into the water and not being
exhausted out the chimney.

In other words, perhaps 50% of the combustion heat of an on-demand
heater is actually being transfered to the incoming cold water and the
other 50% is being lost in the exhaust, while 80% of the combustion heat
is absorbed by the water in a conventional tank. *The difference is that
an on-demand heater is on perhaps 30 to 90 minutes per day, while a
conventional tank might be on for 4 hours a day. *But remember that when
a conventional tank is on, it's burners are using a much smaller amount
of gas compared to the on-demand heater.

5) the efficient use of an on-demand heater is challenged by short
hot-water usage events. *In most houses, the hot water lines are
minimally insulated and thus the water in them quickly drops to room
temperature. *Anyone turning on a hot-water tap in an upstairs bathroom
will notice it take 10 to 30 seconds to actually get hot water. *It
doesn't matter what type of heater you have (assuming the heater is in
the basement). *A short hot-water use event (say, washing your hands)
will end up dumping a lot of waste heat out the exhaust when an
on-demand heater is signalled to turn on and then soon after turned off
to heat the water for that short-use event. *

6) because of the very high heating capability (BTU capacity) of
on-demand heaters, the extreme thermal cycling of their internal
components will age the unit much faster than a conventional water
heater, and they do or will require more maintainence and repair vs a
conventional water heater (they have control devices, electronics, etc,
that are not present in conventional heaters, and as we all know -
electronics and HVAC equipment really don't tend to co-exist very well
for the long term).

7) on-demand heaters have electrical or electronic controls that require
a source of AC current. *Thus they will not function during a power
failure. *Anyone living in a northern climate that is subject to
sporadic winter power failures will not appreciate the lack of hot water
during extended outages.

Conclusion:

No home owner that has a working conventional gas water heater will ever
live long enough to recoup the savings from replacing his existing
working heater with an on-demand unit - and it's not a given that there
will actually be any measureable savings in gas use.

What has been observed is that the behavior of occupants change in terms
of how they use hot water when a conventional heater is replaced with an
on-demand heater, and that change usually results in less hot water use
(shorter showers, changes in shower heads, installation of low-flush
toilets, etc, insulating hot-water supply lines inside the house) so
it's not always clear where the savings come from and why.

Replacing an old / leaking conventional water heater is very easy for
most novice home owners / handymen, and at a cost of only a few hundred
dollars, the cost/reward ratio is still heavily in favor of replacing a
old conventional water heater with a new conventional unit.

You will get more bang-for-the-buck by

1) putting an insulating blanket around your existing or new
conventional water heater

2) insulating as much of the hot water supply lines inside your house as
you can reach

3) use a low-flow shower head

On-demand water heaters are basically a crock of **** designed to give
plumbing and HVAC companies a very lucrative new revenue stream..

You are in cloud cuckoo land if you think the price of any fuel is
going to remain constant. *It's true most American gas appliances of
all descriptions are the most inefficient in the world due to idleness
by manufacturerers and extreme conservatism by buyers.
However, European gas boilers are in excess of 100% in the best cases
and few are less than 95% efficient. You need tolook further afield.
This is the problem with American industry and why it is failing.- Hide quoted text -

- Show quoted text -

You need to go back to school, what you state is nuts. No gas boiler
is over 100% efficient, no gas boiler is 100% efficient, the best is
around 98%. There is wasted heat out the chimney and there is the
loss. If you burn an unvented flame inside like a gas stove, that is
100%- Hide quoted text -

- Show quoted text -

* How can a gas boiler exceed 100% efficiency? *Simply by condensing
the water out of combustion products. this is "extra" heat not
available in non-condensing boilers.
This is mostly latent heat (or heat of vaporisation in your parlance I
believe).
However to achieve this efficiency the heating system has to be
designed for low temperatures on the incoming water. However domestic
hot water is perfect with cold water entering heat exchanger.- Hide quoted text -

- Show quoted text -

There you are wrong, a Btu is a Btu and this is 6th grade stuff, you
cant get back more btus then you put in. Its a fundamental part of
energy. If you could get more out than you put in your reasoning
would lead to perpetual motion of other energy forms. Look at our AFUE
ratings for furnaces, we correctly rate that condensing furnaces and
boilers start at about 92% and go to 98%, its tested and proven by
science you dont get more than you put in burning gas for condensing
units. You still waste energy with condensing units, it goes out the
chimney. I have a condensing furnace, boiler and condensing AO Smith
water tank, None of mine are rated over 96% and nothing sold is rated
over 100%, even 99% is likely a lie as heat is wasted out the
chimney . If your point was correct running a stove would be over 100%
efficient, but it takes energy to condense water.- Hide quoted text -

- Show quoted text -

condensing furnaces and water heaters dont use a chimey they exhaust
thru PVC pipe thru the wall at a very low but slightly warm
temperature.

condensing is more efficent than tankless, if you doubt this just hold
your hand in a standard *tankless exhaust get the burn cream ready
you will need it- Hide quoted text -

- Show quoted text -

Condensing and tankless/instantaneous are unrelated topics. One does
not imply or preclude the other.

- Show quoted text -

condensing furnaces and water heaters dont use a chimey they exhaust
thru PVC pipe thru the wall at a very low but slightly warm
temperature.

condensing is more efficent than tankless, if you doubt this just hold
your hand in a standard *tankless exhaust get the burn cream ready
you will need it- Hide quoted text -

- Show quoted text -

Condensing and tankless/instantaneous are unrelated topics. One does
not imply or preclude the other.

On Nov 21, 7:52*pm, "
wrote:
On Sun, 21 Nov 2010 09:18:27 -0800 (PST), harry wrote:
On Nov 21, 1:43*pm, "Robert Green" wrote:
"harry" wrote in message

....
On Nov 20, 7:05 pm, Joe wrote:

On Nov 20, 12:26 pm, " wrote:

snip
standby losses are overstated, in a heated basement standby loss helps
to keep your home warm in winter..

That's worth repeating for the logically impaired.

standby losses are overstated, in a heated basement standby loss helps
to keep your home warm in winter..

Joe

Heating the basement is not an efficient way to heat your home.
Assuming the OP's water heater is in the basement. Which though common
in America is the most stupid place to put it.

Sure, sure, Harry. *Why not heat the attic? *Oh, heat RISES. *Or has England
managed to repeal the laws of thermodynamics?

Your anti-American screeds are getting pretty tiresome considering that if
you look at some of the world's perpetual trouble spots they're the result
of English imperialism. *India/Pakistan, Northern Ireland, Africa and the
Middle East all have England's bloody handprints on them. *Hell, if King
George acted a little less like King Kong, you might have even been able to
tap into the enormous wealth and resources of your American colony. *But
instead you let a rag-tag bunch of militia men with muskets kick your sorry
Redcoat butts back across the pond to Britain, forcing you to look elsewhere
to build your empire.

As a result, we have the powder keg of India/Pakistan/Kashmir, the nexus of
world terrorism and one of the likely spots that for a nuclear war to begin.
Good job, mate.

Oh, before I forget, the colony that your Parliment tried to squeeze out of
existence with tax after tax still felt enough kinship with you to save your
sorry asses from Hitler in WWII. *You'd be writing these posts in German if
not for the USA. *That's probably what's stuck so deep in your craw, you
hate us because we saved you when all your British BS couldn't protect you
from the German war machine. *My mother's cousin DIED in the merchant marine
bringing your country supplies so that you could survive, so in my view you
really should STFU about the US because I can go toe-to-toe with you. *For
every bad thing the US has done, Britain has done far, far worse. *In some
areas, like Prince Charles wishing he was Camilla's tampon, you're unmatched
in your lunacy.

--
Bobby G.

Oho. There is no more imperialistic state than the USA, an entire
country/continent stolen from it's inhabitants who were systematically
ethnically cleansed, lied to and murdered.

Yeah, England had nothing to do with that, nor would ever think of doing such
in *any* part of the world. *Hypocrite!

Then we need only travel
South. Mexico invaded and large chunks of it's territory stolen.
Nicaragua, Honduras, Salvador, Panama, Colombia, Chile, Cuba Costa
Rica, Philipines, Hawaii. All stolen, attempted to be stolen or
interfered with costong thousands of lives..

Clueless.

And lets be clear. Germany and Japan declared war on you. You came
running to us for help when that happened.

Lies. *You were no position to "help" anyone. *You couldn't even help the rest
of Europe.

There is no such thing as liberty in America.

There is no absolute liberty anywhere, moron.

You are enslaved to your
bankers and wealthy war-mongers, who need perpetual war to enrich
themselves. *You illegally kidnap, torture and kill foriegn
nationals.

Wrong.

You are responsible for the deaths of tens of thousands in
the Middle East.

Not enough.

Your current wars are not about liberty or
democracy, they are to defend Israel and it's fascist zionist land
grabbers and bankers.

Clueless bigot.

So don't lecture me about moral values, the USA has sunk to the levels
of Nazi Germany, with the activities of Bush and Cheney. Self admitted
to breaking the Hague conventions and international law.

Hypocrite.- Hide quoted text -

- Show quoted text -

Clearly you have been watching too many Hollywood films. It may be
news to you but they are 90% fiction. John Wayne did not win WW2.
Boeing did not invent the jet engine and Bill Gates did not invent the
computer. (Haven't I told you this before?). Go and get yourself a
proper education & you will find all the things I revealed to you are
perfectly true.