In article , Ann wrote:

No post (at least that I saw) claimed that setting the thermostat up
increased the rating of a standard residential hot air furnace.

Claiming that setting the thermostat higher than the desired temperature
will cause the room to reach that temperature faster is _exactly_equivalent_
to claiming that setting the thermostat higher than the desired temperature
will increase the output of the furnace. :-)

--
Regards,
Doug Miller (alphageek at milmac dot com)

It's time to throw all their damned tea in the harbor again.

On 2008-01-22, Doug Miller wrote:

No. A thermostat is an on-off switch. As long as the room
temperature is lower than the thermostat's setpoint, it's on. When
the room temperature reaches the setpoint, it turns off. That's all.

The point is that different parts of the house heat up at different
rates, because they have different heat capacities. Air has a low
heat capacity, so it heats up quickest. Denser parts of the house,
e.g. drywall, concrete or plaster, heat up more slowly.

In the usual case, a furnace is just trying to maintain a set
temperature. The heat loss to the outside will be fairly constant,
the temperature differences between different parts of the house
fairly small, and the different rates (heat capacities) of the
building materials not so important.

But if the house starts off "cold", say everything at 50 degrees, and
you want to raise the temperature significantly, say to 70 degrees,
then the different heat capacities have an effect. If you set your
furnace thermostat to 70 degrees, it will shut off when the air around
the thermostat reaches 70 degrees. Other parts of the house that have
higher heat capacities will not have reached 70 degrees yet, so they
will continue to absorb heat and cool the air down.

That is, even though the thermostat shut off, the average temperature
of all the materials in the house is not yet 70 degrees--only the air
temperature is at 70 degrees. As the cooler parts of the house
continue to absorb heat from the air, the air temperature will drop
and cause the furnace to run again to bring the air temperature up to
70 degrees. This process will repeat until all the materials in the
house reach 70 degrees.

Now if you initially set the thermostat to 80 degrees, and then reset
it to 70 degrees, you will initially overshoot your target temperature
by 10 degrees as far as air temperature. But at this point the
average temperature of the materials in the house will be closer to 70
degrees. You will reach equilibrium with everything at 70 degrees
sooner.

Cheers, Wayne

On Tue, 22 Jan 2008 17:00:34 +0000, Doug Miller wrote:

In article , Ann wrote:

No post (at least that I saw) claimed that setting the thermostat up
increased the rating of a standard residential hot air furnace.

Claiming that setting the thermostat higher than the desired temperature
will cause the room to reach that temperature faster is _exactly_equivalent_
to claiming that setting the thermostat higher than the desired temperature
will increase the output of the furnace. :-)

So, who wrote that" (Hint: It wasn't me.)

In article , dpb wrote:
Doug Miller wrote:
In article , Wayne Whitney
wrote:
....

Now if you initially set the thermostat to 80 degrees, and then reset
it to 70 degrees, you will initially overshoot your target temperature
by 10 degrees as far as air temperature. But at this point the
average temperature of the materials in the house will be closer to 70
degrees. You will reach equilibrium with everything at 70 degrees
sooner.

No, you won't. Not unless you've discovered some new laws of thermodynamics.

Well, that's a different question -- if the bulk mass were sufficiently
large, that is at least theoretically possible owing to the higher heat
transfer rate potentially possible when the temperature rises past the
previous setpoint.

Won't be much higher -- heat transfer rate is proportional to absolute
temperature. 70F = 294K; 80F = 299.6K; so the difference between heat transfer
rate at 70F and 80F is less than two percent.

However, it would, I think, be unlikely to actually work that way in
real life to a significant extent as the interior surface temperatures
of the objects being heated are still rising the along the same path as
before until air temperature passes the previous setpoint shutoff point
so there still is only a small (if any) increased delta-T to drive the
supposed increased rate at which the bulk material is going to be
warmed--for most cases, that will be limited by the conduction path into
the material.

Exactly.

Overall, think it would still lose on the efficiency side, might in some
particular instances improve personal comfort slightly although it would
still take the same time to reach the initial setpoint anyway, so by
that time a sweater in the interim would probably be far preferable and
cheaper...

:-)

--
Regards,
Doug Miller (alphageek at milmac dot com)

It's time to throw all their damned tea in the harbor again.

In article , "Gil Faver" wrote:

"Doug Miller" wrote in message
et...

No, you won't. Not unless you've discovered some new laws of
thermodynamics.

it is called heat transfer. more heat in air at 80 will put more heat into
the walls, getting them up to 70 faster. You won't save energy, you will
save time. But, the heat loss out the windows will be greater with a temp
up to 80.

Any difference there might be would be far too small to be noticed. Were you
imagining that heat transfer at 80F is 14% faster than at 70F? Doesn't work
that way. Use absolute temperatures.

--
Regards,
Doug Miller (alphageek at milmac dot com)

It's time to throw all their damned tea in the harbor again.

On Tue, 22 Jan 2008 10:01:53 -0500, Elmo
wrote:

Mark Lloyd wrote:
On Tue, 22 Jan 2008 11:27:05 GMT, (Doug Miller)
wrote:

In article , (Charles Bishop) wrote:

I don't think that's what she said. If you want the temp to be 70, then
set the t-stat to 80. It will cycle once or twice, then set it to 70. This
is from a "cold" start where the temp is way below the setting. It takes
time to bring the furnishings, &c up to temp, so having the t-stat set at
80 helps with this. Yes?
No. A thermostat is an on-off switch. As long as the room temperature is lower
than the thermostat's setpoint, it's on. When the room temperature reaches the
setpoint, it turns off. That's all.

I've found that it does help, even if it shouldn't. At least I've seen
this with a particular gas furnace. When expected to raise the
temperature 20 degrees of so, the furnace would cut off well before
reaching the set temperature.

Most thermostats also have an "anticipator" setting. They will stop calling for heat when the room temperature gets close to the set point. The objective is to prevent the room temperature from oscillating above the set point due to residual heat being released into the room by radiators. It's not usually an issue with hot air systems because they warm the air directly. But hot water, steam, and radiant electric systems usually need it. If you have a hot air system and the anticipator is engaging as if it were a hot water system, that could account for having it cut off too soon.

It was probably the heat anticipator that caused the situation I
described (furnace shutting off too soon).

Now, If I had access to that house in the last 20 years, I might know
what needs fixing. I haven't seen it where I'm now (same type of
furnace).
--
Mark Lloyd
http://notstupid.laughingsquid.com

"All your western theologies, the whole mythology of them,
are based on the concept of God as a senile delinquent."
-- Tennessee Williams

On Tue, 22 Jan 2008 17:00:34 GMT, (Doug Miller)
wrote:

In article , Ann wrote:

No post (at least that I saw) claimed that setting the thermostat up
increased the rating of a standard residential hot air furnace.

Claiming that setting the thermostat higher than the desired temperature
will cause the room to reach that temperature faster is _exactly_equivalent_
to claiming that setting the thermostat higher than the desired temperature
will increase the output of the furnace. :-)

No it isn't. Don't forget about run time.

In this case, we turned on the heat in a 50-degree house, with the
thermostat set for 70. The furnace cut off when the temperature was
about 60. Each additional heat cycle would raise this some until it
got to 70.
--
Mark Lloyd
http://notstupid.laughingsquid.com

"All your western theologies, the whole mythology of them,
are based on the concept of God as a senile delinquent."
-- Tennessee Williams

"Doug Miller" wrote in message
t...
In article ,
"Gil Faver" wrote:

"Doug Miller" wrote in message
. net...

No, you won't. Not unless you've discovered some new laws of
thermodynamics.

it is called heat transfer. more heat in air at 80 will put more heat
into
the walls, getting them up to 70 faster. You won't save energy, you will
save time. But, the heat loss out the windows will be greater with a temp
up to 80.

Any difference there might be would be far too small to be noticed. Were
you
imagining that heat transfer at 80F is 14% faster than at 70F? Doesn't
work
that way. Use absolute temperatures.


hey, this tread long ago drifted off into the theoretical natty gritty.
Don't blame me!

faster is faster. I think we agree on that. I think we also agree on "who
cares - put on a sweater".

On 2008-01-22, Doug Miller wrote:

Won't be much higher -- heat transfer rate is proportional to
absolute temperature. 70F = 294K; 80F = 299.6K; so the difference
between heat transfer rate at 70F and 80F is less than two percent.

Umm, my understanding is that for convection and conduction, heat
transfer rate is proportional to the temperature difference. So there
is a big change in heat transfer rate for 70F versus 80F air.
[E.g. for 60F building materials, the temperature difference is double
with 80F versus 70F air.]

Look at the original question this way--you want to get the average
temperature of a building from 70F to 50F. Based on all the different
materials and their heat capacities, this will require some number of
BTUs; based on the furnace output rate the furnace will have to run
some number of hours to put out the required heat. Say 2 hours.

Air temperature will be a leading indicator of average building
temperature. So if you set your thermostat to 70, the furnace will
run less than two hours, then it will cycle on and off for a while as
the building catches up to the air temperature, until the total
running time reaches two hours. Or you could set the thermostat
artificially high for two hours and then reset it to 70 degrees. The
two hours of furnace time required occurs all at once.

Clearly the latter strategy causes the building to reach equilibrium
sooner. That's all I'm claiming, not that it is a good idea, will be
more comfortable for the occupants, or that it is more efficient.

Cheers, Wayne

According to The hooligan :

Someone mentioned higher voltage being pumped through the lines. Does
this make sense to you who are not electrically challenged? How about
more Hz?

No neither would explain it. Voltage or hz changes big enough to
have this big an effect on your billing would almost certainly
have caused damage to some of your or your neighbor's equipment,
and would probably have been visible during the time.

Actually less hz means more current to inductive devices like
motors, and more hz means less current. hz changes won't do
_anything_ to pure resistive devices.

With many devices, when you raise the voltage, the current
doesn't increase at the same rate, and in some cases even declines.
In a pure resistive device, a 10% increase in voltage comes with
a 10% increase in current - 21% in watts. However, many devices
in a home don't behave that way. Even incandescents significantly
change resistance as the voltage goes up (filament gets hotter). In
other words, V/I isn't a constant in incandescent bulbs or resistive
heat strips.

I'm more thinking of a processing error in their billing cycle. If
you know what the before/after readings were (directly from the
meter) compare that to the bill. It's remotely possible that when
presented with a big gap in the data flow, the billing software
gets confused - eg: a negative increment instead of a positive.
Who knows, perhaps the meter electronics forgot something while
they were unpowered _that_ long.

You seem to be lucky that your utility is also interested in
understanding what's happening. Keep working it - they will
want to figure it out.
--
Chris Lewis,

Age and Treachery will Triumph over Youth and Skill
It's not just anyone who gets a Starship Cruiser class named after them.

In article ,
(Doug Miller) wrote:

In article , Ann
wrote:

No post (at least that I saw) claimed that setting the thermostat up
increased the rating of a standard residential hot air furnace.

Claiming that setting the thermostat higher than the desired temperature
will cause the room to reach that temperature faster is _exactly_equivalent_
to claiming that setting the thermostat higher than the desired temperature
will increase the output of the furnace. :-)

No one claimed that doing so would cause the room to reach temp sooner. I
was claiming (and maybe Ann was as well) that doing so would allow the
room to reach the desired temp with fewer "cycles" of off/on.

I'll try again to explain. If I want my house at 70, I might sent the
t-stat to 80. The furnace comes on, then cycles off as the air near the
t-stat is 80. As the heat in the air warms the rest of the stuff, its temp
drops, and the furnace cyles on. Once the system has done this a few time,
I reset the t-stat to 70.

If I had set it at 70 and left it there it would have reached equilibrium
at roughly the same time, but while it was doing so, the temp in the house
would have been 70 during the periods when the furnace was off, before it
kicks on again. I find this uncomfortble and would rather the chill was
gone while eq. temp is reached.

--
charles

On Tue, 22 Jan 2008 11:27:05 GMT, (Doug Miller) wrote:

In article , (Charles Bishop) wrote:

I don't think that's what she said. If you want the temp to be 70, then
set the t-stat to 80. It will cycle once or twice, then set it to 70. This
is from a "cold" start where the temp is way below the setting. It takes
time to bring the furnishings, &c up to temp, so having the t-stat set at
80 helps with this. Yes?

No. A thermostat is an on-off switch. As long as the room temperature is lower
than the thermostat's setpoint, it's on. When the room temperature reaches the
setpoint, it turns off. That's all.

Not quite. Technically a heat pump thermostat is a 3 state device, off,
refrigeration heat and resistance heat. Anyway,

More to the point, the thermostat responds primarily to AIR temperature and not "room
temperature". Room temperature, as felt by us humans is a mixture of air temperature
and radiant heat transfer back and forth between the masses in the room. Furniture,
walls, etc.

When the thermostat is turned up, the air is heated first. Heat transfer into the
mass becomes greater but is sill slower than air heating. The air reaches the
thermostat's setpoint and the heat turns off. Meanwhile the mass continues absorbing
heat from the air because it is still colder. And occupants feel cold because the
mass is also absorbing heat from their bodies.

The air quickly cools, the thermostat calls for more heat and the cycle continues
until the mass in the room also warms to the setpoint. Then the heat only runs to
make up for losses.

Turning a plain thermostat up initially certainly works to warm things faster, both
because it causes the air to get hotter, speeding heat absorption by the mass, and
because it minimizes the heating plant's off time. In instruments and controls, this
is known as rate or derivative action, instituted manually.

If the operator pays attention and understands thermodynamics and I&C (intuitively,
if not explicitly) then he can turn the 'stat down at the right moment to minimize
overshoot. Just like real rate action does in a process controller.

If the thermostat has an anticipator that is properly adjusted (most 'stats have 'em
but few are adjusted properly) then the anticipator will reduce the time needed to
bring the room up to normal.

If the thermostat is a smart electronic unit then it may have the capability to learn
the room's thermal dynamics and tune itself to maximize warm-up while minimizing
overshoot. Mine does. It takes about 2 cycles after I change the batteries for it
to learn my house. It also optionally inhibits resistance coil operation during
warm-up. This minimizes the loss of economy that heating with resistance heat
instead of the heat pump entails.

Really smart thermostats without outside temperature sensors combined with
multi-stage heating/cooling units, tune themselves to both inside and outside
temperature. I had that setup in my restaurant. It was remarkable how my power bill
dropped when I installed that combo in place of the two single stage heat pumps.

John
--
John De Armond
See my website for my current email address
http://www.neon-john.com
http://www.johndearmond.com -- best little blog on the net!
Tellico Plains, Occupied TN
Daddy, why doesn't this magnet pick up this floppy?

According to Neon John :
No. A thermostat is an on-off switch. As long as the room temperature is lower
than the thermostat's setpoint, it's on. When the room temperature reaches the
setpoint, it turns off. That's all.

Not quite. Technically a heat pump thermostat is a 3 state device, off,
refrigeration heat and resistance heat. Anyway,

Nit-pick: four state: off, refrigeration/heat, defrost (self
nitpick: via controller) and supplementary heat.

The supplementary heat doesn't _have_ to be resistive. Ours (in
a previous house) wasn't. If we go HP again, it won't be.

Really smart thermostats without outside temperature sensors combined with
multi-stage heating/cooling units, tune themselves to both inside and outside
temperature. I had that setup in my restaurant. It was remarkable how
my power bill
dropped when I installed that combo in place of the two single stage heat pumps.

Ours (with gas backup) had two sensors. I don't think it did a lot of
smarts with them, but it was remarkable how low the heating/gas bill
was, even in the great white north.
--
Chris Lewis,

Age and Treachery will Triumph over Youth and Skill
It's not just anyone who gets a Starship Cruiser class named after them.

In article , Mark Lloyd wrote:


In this case, we turned on the heat in a 50-degree house, with the
thermostat set for 70. The furnace cut off when the temperature was
about 60.

That indicates a defective thermostat, which renders the example meaningless.



--
Regards,
Doug Miller (alphageek at milmac dot com)

It's time to throw all their damned tea in the harbor again.

Doug Miller wrote:
In article , Mark Lloyd wrote:


In this case, we turned on the heat in a 50-degree house, with the
thermostat set for 70. The furnace cut off when the temperature was
about 60.


That indicates a defective thermostat, which renders the example meaningless.


Or one not leveled properly, if it is an old Honeywell mercury-switch deal.

nate


--
replace "roosters" with "cox" to reply.
http://members.cox.net/njnagel

Doug Miller wrote:

In article , (Charles Bishop) wrote:


I don't think that's what she said. If you want the temp to be 70, then
set the t-stat to 80. It will cycle once or twice, then set it to 70. This
is from a "cold" start where the temp is way below the setting. It takes
time to bring the furnishings, &c up to temp, so having the t-stat set at
80 helps with this. Yes?


No. A thermostat is an on-off switch. As long as the room temperature is lower
than the thermostat's setpoint, it's on. When the room temperature reaches the
setpoint, it turns off. That's all.

But if you overshoot (keeping it set to a higher air temperature) and
then set it back to your true desire and let the room "soak" you might
reach equilibrium faster.

--
The e-mail address in our reply-to line is reversed in an attempt to
minimize spam. Our true address is of the form .

Doug Miller wrote:

In article , Ann wrote:


No post (at least that I saw) claimed that setting the thermostat up
increased the rating of a standard residential hot air furnace.


Claiming that setting the thermostat higher than the desired temperature
will cause the room to reach that temperature faster is _exactly_equivalent_
^^^^^^^^^^^^^^^^^^^^^^^

Focus on this bit for a minute instead of the bit you've been focused
on. What is "the room?" It's not the thermostat and it's immediate
surroundings. What is "reach?" It's not the first time you're
asymptotically within a delta -- it's when you've established it with
some stability.



to claiming that setting the thermostat higher than the desired temperature
will increase the output of the furnace. :-)



--
The e-mail address in our reply-to line is reversed in an attempt to
minimize spam. Our true address is of the form .

Wayne Whitney wrote:

On 2008-01-22, Doug Miller wrote:


No. A thermostat is an on-off switch. As long as the room
temperature is lower than the thermostat's setpoint, it's on. When
the room temperature reaches the setpoint, it turns off. That's all.


The point is that different parts of the house heat up at different
rates, because they have different heat capacities. Air has a low
heat capacity, so it heats up quickest. Denser parts of the house,
e.g. drywall, concrete or plaster, heat up more slowly.

In the usual case, a furnace is just trying to maintain a set
temperature. The heat loss to the outside will be fairly constant,
the temperature differences between different parts of the house
fairly small, and the different rates (heat capacities) of the
building materials not so important.

But if the house starts off "cold", say everything at 50 degrees, and
you want to raise the temperature significantly, say to 70 degrees,
then the different heat capacities have an effect. If you set your
furnace thermostat to 70 degrees, it will shut off when the air around
the thermostat reaches 70 degrees. Other parts of the house that have
higher heat capacities will not have reached 70 degrees yet, so they
will continue to absorb heat and cool the air down.

That is, even though the thermostat shut off, the average temperature
of all the materials in the house is not yet 70 degrees--only the air
temperature is at 70 degrees. As the cooler parts of the house
continue to absorb heat from the air, the air temperature will drop
and cause the furnace to run again to bring the air temperature up to
70 degrees. This process will repeat until all the materials in the
house reach 70 degrees.

Now if you initially set the thermostat to 80 degrees, and then reset
it to 70 degrees, you will initially overshoot your target temperature
by 10 degrees as far as air temperature. But at this point the
average temperature of the materials in the house will be closer to 70
degrees. You will reach equilibrium with everything at 70 degrees
sooner.

Cheers, Wayne

Well said.

--
The e-mail address in our reply-to line is reversed in an attempt to
minimize spam. Our true address is of the form .

Doug Miller wrote:

In article , Wayne Whitney wrote:

On 2008-01-22, Doug Miller wrote:


No. A thermostat is an on-off switch. As long as the room
temperature is lower than the thermostat's setpoint, it's on. When
the room temperature reaches the setpoint, it turns off. That's all.

The point is that different parts of the house heat up at different
rates, because they have different heat capacities. Air has a low
heat capacity, so it heats up quickest. Denser parts of the house,
e.g. drywall, concrete or plaster, heat up more slowly.

In the usual case, a furnace is just trying to maintain a set
temperature. The heat loss to the outside will be fairly constant,
the temperature differences between different parts of the house
fairly small, and the different rates (heat capacities) of the
building materials not so important.

But if the house starts off "cold", say everything at 50 degrees, and
you want to raise the temperature significantly, say to 70 degrees,
then the different heat capacities have an effect. If you set your
furnace thermostat to 70 degrees, it will shut off when the air around
the thermostat reaches 70 degrees. Other parts of the house that have
higher heat capacities will not have reached 70 degrees yet, so they
will continue to absorb heat and cool the air down.


At which time the furnace will come on again.

That is, even though the thermostat shut off, the average temperature
of all the materials in the house is not yet 70 degrees--only the air
temperature is at 70 degrees. As the cooler parts of the house
continue to absorb heat from the air, the air temperature will drop
and cause the furnace to run again to bring the air temperature up to
70 degrees. This process will repeat until all the materials in the
house reach 70 degrees.

Now if you initially set the thermostat to 80 degrees, and then reset
it to 70 degrees, you will initially overshoot your target temperature
by 10 degrees as far as air temperature. But at this point the
average temperature of the materials in the house will be closer to 70
degrees. You will reach equilibrium with everything at 70 degrees
sooner.


No, you won't. Not unless you've discovered some new laws of thermodynamics.

Which law of thermodynamics is contradicted, and in what manner?

--
The e-mail address in our reply-to line is reversed in an attempt to
minimize spam. Our true address is of the form .

CJT wrote:
Wayne Whitney wrote:
....

...You will reach equilibrium with everything at 70 degrees sooner.
....

Well said.

Even if so (and I think it would take a pretty exceptional house design
for it to make any discernible difference in any practical sense), it
will certainly be more expensive and the time to reach the initial
setpoint is still the same so at best it's a period after that initial
warmup at most that can be affected at all.

--

In article ,
(Doug Miller) wrote:

No. A thermostat is an on-off switch. As long as the room temperature is
lower
than the thermostat's setpoint, it's on. When the room temperature reaches
the
setpoint, it turns off. That's all.

Not true for at least 1 version of mechanical and 1 (probably many)
versions of electronic thermostats, which have means of compensating for
overshoot, and therefore switch at differing points under differing
conditions. Said adjustments are often out of whack if ignorant persons
mess with a thermostat they don't understand the subtleties of, or
install a new one without reading the directions. Thus the automatic
adjustment that someone else mentioned for a newer electronic 'stat.

--
Cats, coffee, chocolate...vices to live by

dpb wrote:

CJT wrote:

Wayne Whitney wrote:

...

...You will reach equilibrium with everything at 70 degrees sooner.

...

Well said.


Even if so (and I think it would take a pretty exceptional house design
for it to make any discernible difference in any practical sense), it
will certainly be more expensive

I don't see why, unless you've got a heat pump with resistive backup.

First order, you need to put the same BTUs in either way to start the
same mass at the same temp and end it at the same temp (although I will
admit to the fact that the path can have a small effect due to the
variation in delta-T's to the outside which affects losses along the
way, but work with me here and assume that the heat needed to go from
cold to warm is most of the energy used and that losses during the
short time involved are second-order).

and the time to reach the initial
setpoint is still the same so at best it's a period after that initial
warmup at most that can be affected at all.

--




--
The e-mail address in our reply-to line is reversed in an attempt to
minimize spam. Our true address is of the form .

CJT wrote:
dpb wrote:

CJT wrote:
....

...it will certainly be more expensive

I don't see why, ...

Because the input to reach the higher setpoint will also have higher
proportional losses owing to the higher delta-T to the outside.

--

dpb wrote:
CJT wrote:

dpb wrote:

CJT wrote:

...

...it will certainly be more expensive


I don't see why, ...


Because the input to reach the higher setpoint will also have higher
proportional losses owing to the higher delta-T to the outside.

--
Sure, and I recognized that (in the part you snipped), but I think it's
small relative to the heat required to heat up the house and everything
in it.

--
The e-mail address in our reply-to line is reversed in an attempt to
minimize spam. Our true address is of the form .

CJT wrote:
dpb wrote:
CJT wrote:

dpb wrote:

CJT wrote:

...

...it will certainly be more expensive


I don't see why, ...


Because the input to reach the higher setpoint will also have higher
proportional losses owing to the higher delta-T to the outside.

--
Sure, and I recognized that (in the part you snipped), but I think it's
small relative to the heat required to heat up the house and everything
in it.

But, it's as real as the heat going into the material is and at higher
dT the loss proportion goes up at the same rate as the gain portion so
you can't win -- you might come close to breaking even, but you can't
win. Well, actually I guess you could possibly break even in one
specific instance but it would take really detailed measurements or
calculations to come to that point--if you were to be able to find the
time at which the exterior wall temperatures would first reach their
steady-state temperature and cut the extra input at the time when the
heat input on the inside surface would then be transferred to reach that
exterior temperature, then it would be the break-even point. Once the
interior temperature is higher than that, then the exterior temperature
also would rise above its steady-state value and then the previous
conclusion would also hold.

The point in my view is that the two paths are identical owing to the
fixed input until the lower setpoint is reached so there's absolutely no
advantage there. The only question is whether then raising the
temperature above the end setpoint perhaps aids a little _from that
point_ in "creature comfort" -- my opinion is that unless the house is
one that is actually designed as a thermal mass rather than conventional
likely to be essentially unchanged although it just might aid a little
bit in "taking the chill" off in comfort level. But it can't help but
be more energy-costly and can't help the initial recovery.

--

--

On Tue, 22 Jan 2008 20:34:01 GMT, (Doug Miller)
wrote:

In article , "Gil Faver" wrote:

"Doug Miller" wrote in message
. net...

No, you won't. Not unless you've discovered some new laws of
thermodynamics.

it is called heat transfer. more heat in air at 80 will put more heat into
the walls, getting them up to 70 faster. You won't save energy, you will
save time. But, the heat loss out the windows will be greater with a temp
up to 80.

Any difference there might be would be far too small to be noticed. Were you
imagining that heat transfer at 80F is 14% faster than at 70F? Doesn't work
that way. Use absolute temperatures.

That's the problem with using deg F, it bears no relation to reality



--

On Tue, 22 Jan 2008 14:06:34 -0800, (Charles
Bishop) wrote:

I'll try again to explain. If I want my house at 70, I might sent the
t-stat to 80. The furnace comes on, then cycles off as the air near the
t-stat is 80. As the heat in the air warms the rest of the stuff, its temp
drops, and the furnace cyles on. Once the system has done this a few time,
I reset the t-stat to 70.

How quaint. You're obviously American.

The rest of the planet understands thermostats.


--

Mike wrote:
On Tue, 22 Jan 2008 14:06:34 -0800, (Charles
Bishop) wrote:

I'll try again to explain. If I want my house at 70, I might sent the
t-stat to 80. The furnace comes on, then cycles off as the air near the
t-stat is 80. As the heat in the air warms the rest of the stuff, its temp
drops, and the furnace cyles on. Once the system has done this a few time,
I reset the t-stat to 70.

How quaint. You're obviously American.

The rest of the planet understands thermostats.



Methinks you exaggerate. I've seen places in other countries where
the people live in unheated buildings. I'm reasonably certain some
of them don't understand thermostats.

--
He's so slick that he can't keep his socks up.

On Wed, 23 Jan 2008 01:43:09 GMT, (Doug Miller)
wrote:

In article , Mark Lloyd wrote:


In this case, we turned on the heat in a 50-degree house, with the
thermostat set for 70. The furnace cut off when the temperature was
about 60.

That indicates a defective thermostat, which renders the example meaningless.

That is what HAPPENED (defective or not). How is reality meaningless?
Are you saying it is now impossible for thermostats to be defective?
--
Mark Lloyd
http://notstupid.laughingsquid.com

"All your western theologies, the whole mythology of them,
are based on the concept of God as a senile delinquent."
-- Tennessee Williams

On Tue, 22 Jan 2008 20:46:51 -0500, Nate Nagel
wrote:

Doug Miller wrote:
In article , Mark Lloyd wrote:


In this case, we turned on the heat in a 50-degree house, with the
thermostat set for 70. The furnace cut off when the temperature was
about 60.


That indicates a defective thermostat, which renders the example meaningless.


Or one not leveled properly, if it is an old Honeywell mercury-switch deal.


I don't remember the brand, but it defiantly did use a mercury switch.
This happened around 1974.

nate

Still it made no sense to call it meaningless.
--
Mark Lloyd
http://notstupid.laughingsquid.com

"All your western theologies, the whole mythology of them,
are based on the concept of God as a senile delinquent."
-- Tennessee Williams

On Sat, 26 Jan 2008 16:48:54 -0500, "daestrom"
wrote:


"Neon John" wrote in message
.. .
On Tue, 22 Jan 2008 11:27:05 GMT, (Doug Miller) wrote:

In article
,
(Charles Bishop) wrote:


If the thermostat has an anticipator that is properly adjusted (most
'stats have 'em
but few are adjusted properly) then the anticipator will reduce the time
needed to
bring the room up to normal.


Actually, the classic heating thermostat anticipator is a tiny heater that
warms the sensing element a degree or two above the room's air temperature.
The purpose is to cause the burner of the furnace to shut off just before
the room reaches the desired temperature. This works because even after the
burner shuts off, the heat-exchanger in the furnace and the blower continue
to supply heat to the room for close to a minute longer. When properly
adjusted, the burner will shut off just before the room air reaches the
setpoint and the stored heat in the hot heat exchanger will continue and the
room temperature will 'coast' up to the setpoint just as the blower shuts
off.

This feature avoids an overshoot of the room temperature, but doesn't do
anything to '...reduce the time needed to bring the room up to normal.'

daestrom

Even if it has been turning the furnace off too soon, requiring the
user to wait for another heat cycle?
--
Mark Lloyd
http://notstupid.laughingsquid.com

"So far as I can remember, there is not one word
in the Gospels in praise of intelligence."
--Bertrand Russell

On Sun, 27 Jan 2008 10:15:07 -0600, "Duane C. Johnson"
wrote:

Mark Lloyd wrote:
On Sat, 26 Jan 2008 16:48:54 -0500, "daestrom"
wrote:


"Neon John" wrote in message
...

On Tue, 22 Jan 2008 11:27:05 GMT, (Doug Miller) wrote:


In article
,
(Charles Bishop) wrote:


If the thermostat has an anticipator that is properly adjusted (most
'stats have 'em
but few are adjusted properly) then the anticipator will reduce the time
needed to
bring the room up to normal.


Actually, the classic heating thermostat anticipator is a tiny heater that
warms the sensing element a degree or two above the room's air temperature.
The purpose is to cause the burner of the furnace to shut off just before
the room reaches the desired temperature. This works because even after the
burner shuts off, the heat-exchanger in the furnace and the blower continue
to supply heat to the room for close to a minute longer. When properly
adjusted, the burner will shut off just before the room air reaches the
setpoint and the stored heat in the hot heat exchanger will continue and the
room temperature will 'coast' up to the setpoint just as the blower shuts
off.

This feature avoids an overshoot of the room temperature, but doesn't do
anything to '...reduce the time needed to bring the room up to normal.'

daestrom


Even if it has been turning the furnace off too soon, requiring the
user to wait for another heat cycle?

Then you adjust the antisipator so it doesn't.
It's relativly easy to do.


I didn't know about the heat anticipator 30 years ago, when I noticed
the problem.

It was a case of the heat anticipator affecting 'the time needed to
bring the room up to normal.'

Duane
--
Mark Lloyd
http://notstupid.laughingsquid.com

"So far as I can remember, there is not one word
in the Gospels in praise of intelligence."
--Bertrand Russell

Mark Lloyd wrote:
On Sat, 26 Jan 2008 16:48:54 -0500, "daestrom"
wrote:


"Neon John" wrote in message
. ..

On Tue, 22 Jan 2008 11:27:05 GMT, (Doug Miller) wrote:


In article
,
(Charles Bishop) wrote:


If the thermostat has an anticipator that is properly adjusted (most
'stats have 'em
but few are adjusted properly) then the anticipator will reduce the time
needed to
bring the room up to normal.


Actually, the classic heating thermostat anticipator is a tiny heater that
warms the sensing element a degree or two above the room's air temperature.
The purpose is to cause the burner of the furnace to shut off just before
the room reaches the desired temperature. This works because even after the
burner shuts off, the heat-exchanger in the furnace and the blower continue
to supply heat to the room for close to a minute longer. When properly
adjusted, the burner will shut off just before the room air reaches the
setpoint and the stored heat in the hot heat exchanger will continue and the
room temperature will 'coast' up to the setpoint just as the blower shuts
off.

This feature avoids an overshoot of the room temperature, but doesn't do
anything to '...reduce the time needed to bring the room up to normal.'

daestrom


Even if it has been turning the furnace off too soon, requiring the
user to wait for another heat cycle?

Then you adjust the antisipator so it doesn't.
It's relativly easy to do.

Duane

--
Home of the $35 Solar Tracker Receiver
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