Thought some of you might like to know the best buys in Which?
Best combis:

Baxi Duo-tec
Potterton Gold
Vaillant ecoTEC
Vaillant ecoTEC(Larger model)

The Baxi and Vaillant were the only two boilers that met the claim of
91% efficiency.

Bottom of list we
Ideal Isar
Worcester Junior (Always thought these boilers had an over- inflated
opinion)
Potterton performa
Forgot the rest, but these boilers did not meet efficiency claim.

No open vent boilers were best buys but the top of list was the
Vaillant and at the bottom was the Potterton promax

The next boiler after the 4 best buys was a Boulter Buderus

wrote in message
...
Thought some of you might like to know the best buys in Which?
Best combis:

Baxi Duo-tec
Potterton Gold
Vaillant ecoTEC
Vaillant ecoTEC(Larger model)

The Baxi and Vaillant were the only two boilers that met the claim of
91% efficiency.

Bottom of list we
Ideal Isar
Worcester Junior (Always thought these boilers had an over- inflated
opinion)
Potterton performa
Forgot the rest, but these boilers did not meet efficiency claim.

No open vent boilers were best buys but the top of list was the
Vaillant and at the bottom was the Potterton promax

The next boiler after the 4 best buys was a Boulter Buderus

All very interesting. Buderus is good. How about long term reliability?
Baxi/Potterton don't look good then. Did they test an Atmos, I doubt it.
Buy an Atmos.

"Doctor Drivel" wrote in message
reenews.net...

wrote in message
...
Thought some of you might like to know the best buys in Which?
Best combis:

Baxi Duo-tec
Potterton Gold
Vaillant ecoTEC
Vaillant ecoTEC(Larger model)

The Baxi and Vaillant were the only two boilers that met the claim of
91% efficiency.

Bottom of list we
Ideal Isar
Worcester Junior (Always thought these boilers had an over- inflated
opinion)
Potterton performa
Forgot the rest, but these boilers did not meet efficiency claim.

No open vent boilers were best buys but the top of list was the
Vaillant and at the bottom was the Potterton promax

The next boiler after the 4 best buys was a Boulter Buderus

All very interesting. Buderus is good. How about long term reliability?
Baxi/Potterton don't look good then. Did they test an Atmos, I doubt it.
Buy an Atmos.

Mmm - were the tests biased towards those that a small child could not poke
a finger inside.

"John" wrote in message
news

"Doctor Drivel" wrote in message
reenews.net...

wrote in message
...
Thought some of you might like to know the best buys in Which?
Best combis:

Baxi Duo-tec
Potterton Gold
Vaillant ecoTEC
Vaillant ecoTEC(Larger model)

The Baxi and Vaillant were the only two boilers that met the claim of
91% efficiency.

Bottom of list we
Ideal Isar
Worcester Junior (Always thought these boilers had an over- inflated
opinion)
Potterton performa
Forgot the rest, but these boilers did not meet efficiency claim.

No open vent boilers were best buys but the top of list was the
Vaillant and at the bottom was the Potterton promax

The next boiler after the 4 best buys was a Boulter Buderus

All very interesting. Buderus is good. How about long term reliability?
Baxi/Potterton don't look good then. Did they test an Atmos, I doubt it.
Buy an Atmos.

Mmm - were the tests biased towards those that a small child could not
poke a finger inside.

Every Which report on boilers I have come across have been crap. They are
very naive.

In message
,
writes
Thought some of you might like to know the best buys in Which?
Best combis:

Baxi Duo-tec
Potterton Gold
Vaillant ecoTEC
Vaillant ecoTEC(Larger model)

I bet the Suprima was up there when it first came out ...


--
geoff

wrote:
Thought some of you might like to know the best buys in Which?

What was their selection criteria?



--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

wrote:
Thought some of you might like to know the best buys in Which?

Bottom of list we
Ideal Isar
Worcester Junior (Always thought these boilers had an over- inflated
opinion)

Why didn't they like Worcesters?
Every fitter I come across seems to swear by them (Ok, maybe easy to
fit...?)

David

Lobster wrote:

Why didn't they like Worcesters?
Every fitter I come across seems to swear by them (Ok, maybe easy to
fit...?)

Having just had a glance at the non subscription bits, I get the
impression that they are not too on the ball anyway:

"Nearly all new boilers are now 'condensing' types. Condensing boilers
are far more energy-efficient than traditional boilers, as they
cunningly reuse heat that would otherwise be wasted.

Some heat generated by traditional boilers disappears up the flue in the
form of hot waste gases. But condensing boilers use some of the heat
from these flue gases to heat water, making the boiler far more efficient."

That would be a "woosh" then ;-)



--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On 2007-12-22 03:53:41 +0000, John Rumm said:

Lobster wrote:

Why didn't they like Worcesters?
Every fitter I come across seems to swear by them (Ok, maybe easy to fit...?)

Having just had a glance at the non subscription bits, I get the
impression that they are not too on the ball anyway:

"Nearly all new boilers are now 'condensing' types. Condensing boilers
are far more energy-efficient than traditional boilers, as they
cunningly reuse heat that would otherwise be wasted.

Some heat generated by traditional boilers disappears up the flue in
the form of hot waste gases. But condensing boilers use some of the
heat from these flue gases to heat water, making the boiler far more
efficient."

That would be a "woosh" then ;-)

One also wonders how they made the efficiency measurements; especially
when SEDBUK says:

"Statistical analysis suggests that if two boilers have SEDBUK values 3
percentage points apart then there is 95% confidence that the boiler
with the higher value is more efficient."


What they don't say is what the confidence level is when the figures
are only 1 - 1.5% apart. Also, one wonders what the accuracy of
measurement is. Better than 1%? That would be surprising.
Which? being able to make the measurements? Even more surprising.

No open vent boilers were best buys but the top of list was the
Vaillant and at the bottom was the Potterton promax

From the online version they appear to have made no comment on or
allowance for (i) the effect of the return temperature on efficiency or
(ii) the cost of upgrading radiators in order to make it practicable to
reduce the return temperature. Is it naughty of them to show potential
savings on heating bills based on 90% efficiency and costs for boilers
alone?

For me (with 20+ year old albeit unvented system and separate multipoint
water heater) in a small Victorian terrace with suspended floors the
need to upgrade radiators in order to get anywhere near 90% has been a
big factor in doing nowt. Or (as is increasingly likely) have I
misunderstood what wd be involved?

--
Robin

On 2007-12-21 21:28:16 +0000, said:

Thought some of you might like to know the best buys in Which?
Best combis:

Baxi Duo-tec
Potterton Gold
Vaillant ecoTEC
Vaillant ecoTEC(Larger model)

The Baxi and Vaillant were the only two boilers that met the claim of
91% efficiency.

Bottom of list we
Ideal Isar
Worcester Junior (Always thought these boilers had an over- inflated
opinion)
Potterton performa
Forgot the rest, but these boilers did not meet efficiency claim.

No open vent boilers were best buys but the top of list was the
Vaillant and at the bottom was the Potterton promax

The next boiler after the 4 best buys was a Boulter Buderus

The range of efficiencies of modern condensing boilers is in the range
from 90 - 91.5%.

SEDBUK say that where there are two boilers with 3% difference there is
a 95% confidence that one will be better than the other. They don't
say what the confidence is when the difference is only 0.5% or 1%, but
obviously less.
can measurements be made consistently to a fraction of a percent?
Seems unlikely considering the many factors involved.

Consider also the energy cost saving between 90 and 91% (assuming the
figures are reached).

A much more important set of criteria at this point becomes build
quality and servicability.

On 2007-12-22 10:43:32 +0000, "neverwas" said:

No open vent boilers were best buys but the top of list was the
Vaillant and at the bottom was the Potterton promax

From the online version they appear to have made no comment on or
allowance for (i) the effect of the return temperature on efficiency or
(ii) the cost of upgrading radiators in order to make it practicable to
reduce the return temperature. Is it naughty of them to show potential
savings on heating bills based on 90% efficiency and costs for boilers
alone?

For me (with 20+ year old albeit unvented system and separate multipoint
water heater) in a small Victorian terrace with suspended floors the
need to upgrade radiators in order to get anywhere near 90% has been a
big factor in doing nowt. Or (as is increasingly likely) have I
misunderstood what wd be involved?

The issue is a comparative one.

Increasing radiator sizes does allow the return temperature to be
reduced for a given heat output. However in terms of what is needed
and achieved, there are a number of factors:

- Assuming that the radiators were only just adequately sized for 82/70
conventional operation in coldest weather, then the boiler will still
run at relatively low temperatures during the 6-8 months of the year
when only small amounts of heat are needed - i.e. max operation is only
usually for 1-2 months of the year.

- Some or all of the radiators may well be oversized anyway.

I found that I was able to redesign for 70/50 operation by leaving most
radiators alone, moving three to new positions and replacing those.

In any case, even if the 90% figures are not met if the existing boiler
is one of the older wall mounted natural ventilation types like I had,
the starting point was 65%, and there would easily be an improvement in
that.

Andy Hall wrote:
On 2007-12-21 21:28:16 +0000, said:

Thought some of you might like to know the best buys in Which?
Best combis:

Baxi Duo-tec
Potterton Gold
Vaillant ecoTEC
Vaillant ecoTEC(Larger model)

The Baxi and Vaillant were the only two boilers that met the claim of
91% efficiency.

Bottom of list we
Ideal Isar
Worcester Junior (Always thought these boilers had an over- inflated
opinion)
Potterton performa
Forgot the rest, but these boilers did not meet efficiency claim.

No open vent boilers were best buys but the top of list was the
Vaillant and at the bottom was the Potterton promax

The next boiler after the 4 best buys was a Boulter Buderus

The range of efficiencies of modern condensing boilers is in the range
from 90 - 91.5%.

SEDBUK say that where there are two boilers with 3% difference there is
a 95% confidence that one will be better than the other. They don't
say what the confidence is when the difference is only 0.5% or 1%, but
obviously less.

Well AIUI in science if you're using a statistical test to determine
whether A is different from B using whatever measurement or assessment,
then if there is less than a 95% (tytpically) chance of the measurements
being different then you cannot claim that there is any difference.

If so, then the above would indicate that there is actually no
statistically significant difference between the efficiencies of any
modern condensing boilers.

Does that sound about right?

David

On 2007-12-22 11:34:29 +0000, Lobster said:

Andy Hall wrote:

The range of efficiencies of modern condensing boilers is in the range
from 90 - 91.5%.

SEDBUK say that where there are two boilers with 3% difference there is
a 95% confidence that one will be better than the other. They don't
say what the confidence is when the difference is only 0.5% or 1%, but
obviously less.

Well AIUI in science if you're using a statistical test to determine
whether A is different from B using whatever measurement or assessment,
then if there is less than a 95% (tytpically) chance of the
measurements being different then you cannot claim that there is any
difference.

If so, then the above would indicate that there is actually no
statistically significant difference between the efficiencies of any
modern condensing boilers.

Does that sound about right?

David

I think that at least it puts it into the context of being a second
order issue.

However, if the manufacturer was claiming 90.3% and the boiler only
does 85% it would be a different matter, but I think that that would be
surprising.

In article ,
Lobster writes:
Well AIUI in science if you're using a statistical test to determine
whether A is different from B using whatever measurement or assessment,
then if there is less than a 95% (tytpically) chance of the measurements
being different then you cannot claim that there is any difference.

At University, in the department of Physics and Astronomy,
the business of being within 3 standard deviations was often
quoted. The Physicists were required 3 SD's in the mantissa,
but the Astronomers were allowed their 3 SD's in the exponent ;-)

If so, then the above would indicate that there is actually no
statistically significant difference between the efficiencies of any
modern condensing boilers.

Does that sound about right?

That's probably right for the basic combustion -- I suspect
they all eject the flue gasses at around only 5C hotter than
the return water temperature..

However, there's much scope for the control system to optimse
the efficiency.

e.g. inside the boiler by accurately setting the flow and return
temperatures to their optimim values (low as possible whilst
getting exactly the right amount of heat into the house).
I don't think many of the condensing boilers (particularly the
cheaper ones) even attempt this. I see lots of condensing
boilers with the water temperature still set high when it's
not necessary -- I suspect few owners actually understand what
the controls do in any detail.

Then there are the external control systems -- timeswitches and
crude thermostats can be bettered with control systems which
implement setbacks, and know about the occupancy of the house
and even occupancy of separate zones. Mine is integrated with
my burglar alarm (as it also knows things like occupancy of
areas of the house), but that kind of system design is still
very rare.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

John Rumm wrote:

"Nearly all new boilers are now 'condensing' types. Condensing boilers
are far more energy-efficient than traditional boilers, as they
cunningly reuse heat that would otherwise be wasted.

Some heat generated by traditional boilers disappears up the flue in the
form of hot waste gases. But condensing boilers use some of the heat
from these flue gases to heat water, making the boiler far more efficient."

That would be a "woosh" then ;-)

That's alright, isn't it? Water vapour is a gas and latent heat is heat.

--
Andy

"neverwas" wrote in message
news
No open vent boilers were best buys but the top of list was the
Vaillant and at the bottom was the Potterton promax

From the online version they appear to have made no comment on or
allowance for (i) the effect of the return temperature on efficiency or
(ii) the cost of upgrading radiators in order to make it practicable to
reduce the return temperature. Is it naughty of them to show potential
savings on heating bills based on 90% efficiency and costs for boilers
alone?

For me (with 20+ year old albeit unvented system and separate multipoint
water heater) in a small Victorian terrace with suspended floors the need
to upgrade radiators in order to get anywhere near 90% has been a big
factor in doing nowt. Or (as is increasingly likely) have I misunderstood
what wd be involved?

You are better off sealing the loft from the rooms below and have 1 foot of
insulation in the loft. That will bring better returns. Also have better
controls on the CH system.

"Andrew Gabriel" wrote in message
...

However, there's much scope for the control system to optimse
the efficiency.

e.g. inside the boiler by accurately setting the flow and return
temperatures to their optimim values (low as possible whilst
getting exactly the right amount of heat into the house).

This is where a weather compensator shines. They mate well with condensing
boilers.

Even a BIASI model has an integral weather compensator.

On Sat, 22 Dec 2007 10:43:32 +0000, neverwas wrote:

No open vent boilers were best buys but the top of list was the
Vaillant and at the bottom was the Potterton promax

From the online version they appear to have made no comment on or
allowance for (i) the effect of the return temperature on efficiency or
(ii) the cost of upgrading radiators in order to make it practicable to
reduce the return temperature. Is it naughty of them to show potential
savings on heating bills based on 90% efficiency and costs for boilers
alone?

For me (with 20+ year old albeit unvented system and separate multipoint
water heater) in a small Victorian terrace with suspended floors the
need to upgrade radiators in order to get anywhere near 90% has been a
big factor in doing nowt. Or (as is increasingly likely) have I
misunderstood what wd be involved?

I would have to say to you that doing nothing because of trying to
upgrade to a perfect installation is unwise. There are real and
substantial saving to be made with a modern boiler and controls.

Most of the boiler improvement comes not from the condensing itself but
form a better heat exchanger in which condensing can and does happen.
The condensing is a bonus and increasing the emitters to reduce the
return temp is a further bonus.

--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html

I would have to say to you that doing nothing because of trying to
upgrade to a perfect installation is unwise. There are real and
substantial saving to be made with a modern boiler and controls.

Most of the boiler improvement comes not from the condensing itself
but
form a better heat exchanger in which condensing can and does happen.
The condensing is a bonus and increasing the emitters to reduce the
return temp is a further bonus.

Thanks. Understood and fully accepted. (A fuller account would have
gone on to say that I would expect to be able to get around 80% which
will be worth doing now we do not get the benefit of trogging off to
heated offices - but only after we have sorted out the roof, which comes
after sorting out the subsidence recently discovered..... )

In passing, I have now also read the printed report in Which? and still
think they are naughty not to explain what is required to get to 90%
efficiency.

--
Robin

In message , Andrew Gabriel
writes
Then there are the external control systems -- timeswitches and
crude thermostats can be bettered with control systems which
implement setbacks, and know about the occupancy of the house
and even occupancy of separate zones. Mine is integrated with
my burglar alarm

That's thoughtful of you

making sure they don't catch a chill while robbing you


--
geoff

"geoff" wrote in message
...
In message , Andrew Gabriel
writes
Then there are the external control systems -- timeswitches and
crude thermostats can be bettered with control systems which
implement setbacks, and know about the occupancy of the house
and even occupancy of separate zones. Mine is integrated with
my burglar alarm

That's thoughtful of you

making sure they don't catch a chill while robbing you

Maxie, you are a breath of fresh air.

On Sat, 22 Dec 2007 10:48:22 +0000, Andy Hall
wrote:

snip
The range of efficiencies of modern condensing boilers is in the range
from 90 - 91.5%.

SEDBUK say that where there are two boilers with 3% difference there is
a 95% confidence that one will be better than the other. They don't
say what the confidence is when the difference is only 0.5% or 1%, but
obviously less.
can measurements be made consistently to a fraction of a percent?
Seems unlikely considering the many factors involved.

Consider also the energy cost saving between 90 and 91% (assuming the
figures are reached).

A much more important set of criteria at this point becomes build
quality and servicability.


The discussion on boiler efficiency may be interesting but really is
irrelevant if you accept that the difference of efficiency of modern
boilers will fall within a 10% envelope. For most, I suggest this
equates to something like £50-£60 in their annual gas bill. If we can
agree that a call out charge for servicing is of the same order, more
if it requires part replacement,cost of repair and servicing are the
more important criteria. I know this has been raised by many but 'we'
still persist with focusing on boiler efficiency.

Further, the cost to replace a boiler, non DIY, is what, something of
the order of £1500 plus? If the reason is purely to benefit from
gains in efficiency and we agree the efficiency of a non condensing
boiler is 60%, repayment on cost will be 15 years plus, hardly worth
considering.

In my judgement it is economically advantageous to keep a non
condensing boiler in service for as long as economically possible. How
long that is will obviously vary from case to case but to replace a
boiler to benefit from gains in efficiency is not a factor.

I know there is nothing new here but I would really benefit from
changing the focus of the discussion from efficiency to reliabilty and
cost of ownership.

On 2007-12-23 07:02:50 +0000, Edward W. Thompson
said:

On Sat, 22 Dec 2007 10:48:22 +0000, Andy Hall
wrote:

snip
The range of efficiencies of modern condensing boilers is in the range
from 90 - 91.5%.

SEDBUK say that where there are two boilers with 3% difference there is
a 95% confidence that one will be better than the other. They don't
say what the confidence is when the difference is only 0.5% or 1%, but
obviously less.
can measurements be made consistently to a fraction of a percent?
Seems unlikely considering the many factors involved.

Consider also the energy cost saving between 90 and 91% (assuming the
figures are reached).

A much more important set of criteria at this point becomes build
quality and servicability.


The discussion on boiler efficiency may be interesting but really is
irrelevant if you accept that the difference of efficiency of modern
boilers will fall within a 10% envelope. For most, I suggest this
equates to something like £50-£60 in their annual gas bill.

On the most recent models it's in about a 3% window allowing fo
rmeasurement uncertainties and the difference in gas bill perhaps
around £15.

As you suggest, in the scheme of things, almost negligible.



If we can
agree that a call out charge for servicing is of the same order, more
if it requires part replacement,cost of repair and servicing are the
more important criteria. I know this has been raised by many but 'we'
still persist with focusing on boiler efficiency.

A call out charge for a service is probably closer to £100.




Further, the cost to replace a boiler, non DIY, is what, something of
the order of £1500 plus? If the reason is purely to benefit from
gains in efficiency and we agree the efficiency of a non condensing
boiler is 60%, repayment on cost will be 15 years plus, hardly worth
considering.



In my judgement it is economically advantageous to keep a non
condensing boiler in service for as long as economically possible. How
long that is will obviously vary from case to case but to replace a
boiler to benefit from gains in efficiency is not a factor.

I know there is nothing new here but I would really benefit from
changing the focus of the discussion from efficiency to reliabilty and
cost of ownership.

It depends on the point from which one is measuring and projecting and
isn't a simple linear discussion.

On the one hand, if one has a an existing old boiler that is 15 -20
years old and has 60% efficiency then the capital cost is long written
down and the discussion is about the cost in parts of keeping it
running. That one is a fairly simple game of costing. If a
failure is from a thermocouple or perhaps a thermostat, it is probably
economic to continue with it. If a failure is from the heat exchanger
or gas valve, probably not.

On the other hand, if the boiler is a more recent model, it may already
have a 70-75% efficiency and may also not be written down. Then the
replacement of even the more expensive parts may be viable.

One also has to factor in the increasing cost of gas (say 10-15% pa);
although at this point that is still a second order factor - being a
percentage of a percentage.

On that first level, I would agree with you. If a boiler is already
running well and has some lifetime left, and remains servicable
economically, there is no point on a purely financial basis to change
it.


There can be other triggers for changing a boiler:

- Change in usage pattern - e.g. more people in the house, building of
an extension

- Original was never up to the job

- Need to relocate the boiler


For me it was a mixture of criteria:

- The old boiler was 15 years old and had had a new thermostat.
There were signs of deterioration from the heat exchanger.

- It was a 65% efficient model and had been written down

- It was necessary to move it owing to a kitchen remodeling

- Additions were being made to the property in terms of a conservatory
and heating for the workshop and it would not have been adequate.

On the basis of these, I felt that there was a fairly clear decision to
replace. Having made that decision, the choice of replacement was
based on build quality, test reports (in my case from Germany),
research of different models and on servicability. I did not decide
based on whether a product was 90 or 91% efficient. As it happened,
the model chosen was at the top end of efficiency at the time (there
are others than are more efficient now but only by about 1%). There
was a 5 year parts and labour warranty.

All of that put the purchase price into the top decile of gas boiler
prices among condensing models.

The other thing that I do is to maintain a slush fund for replacement
of domestic equipment. My philosophy for that is to choose only high
quality products - e.g. Miele for white goods and to write the cost
down on a more aggressive basis than the likely lifetime. So for
example, boiler, washing machine, tumble dryer is 10 years. I know
that I am safe with the Miele appliances because the warranty is 10
years. I am taking a reasonable punt with the boiler. For each
year's contribution to the slush fund, I put in an amount to replace
with something from the top decile of products of the type and add 10%
to that to compensate inflation.
This works pretty well and always remains in "profit".


It would be very hard to find TCO for a boiler based on repair costs.
Manufacturers know what they are funding in terms of spares during
warranty. They also know what they are selling out in terms of spares
after that, plus they know the size of the installed base. Of course,
they won't tell you that. Then there is the issue of generic parts
(although those are generally the low cost ones).

Given all of that, there is not much to go on, other than the common
sense things of looking at build quality - a Viessmann or Vaillant is
better built than a Ravenheat - something obvious to anybody taking the
trouble to research.

Then you can talk to those who actually fix the things independently
but don't have an axe to grind commercially.

In those senses, we do have several people here who give honest
opinions based on their experiences.

I don't think that it gets more scientific than that.

Andy Hall wrote:
On 2007-12-23 07:02:50 +0000, Edward W. Thompson
said:

On Sat, 22 Dec 2007 10:48:22 +0000, Andy Hall
wrote:

snip
The range of efficiencies of modern condensing boilers is in the range
from 90 - 91.5%.

SEDBUK say that where there are two boilers with 3% difference there is
a 95% confidence that one will be better than the other. They don't
say what the confidence is when the difference is only 0.5% or 1%, but
obviously less.
can measurements be made consistently to a fraction of a percent?
Seems unlikely considering the many factors involved.

Consider also the energy cost saving between 90 and 91% (assuming the
figures are reached).

A much more important set of criteria at this point becomes build
quality and servicability.


The discussion on boiler efficiency may be interesting but really is
irrelevant if you accept that the difference of efficiency of modern
boilers will fall within a 10% envelope. For most, I suggest this
equates to something like �50-�60 in their annual gas bill.

On the most recent models it's in about a 3% window allowing fo
rmeasurement uncertainties and the difference in gas bill perhaps around
�15.

As you suggest, in the scheme of things, almost negligible.



If we can
agree that a call out charge for servicing is of the same order, more
if it requires part replacement,cost of repair and servicing are the
more important criteria. I know this has been raised by many but 'we'
still persist with focusing on boiler efficiency.

A call out charge for a service is probably closer to �100.




Further, the cost to replace a boiler, non DIY, is what, something of
the order of �1500 plus? If the reason is purely to benefit from
gains in efficiency and we agree the efficiency of a non condensing
boiler is 60%, repayment on cost will be 15 years plus, hardly worth
considering.



In my judgement it is economically advantageous to keep a non
condensing boiler in service for as long as economically possible. How
long that is will obviously vary from case to case but to replace a
boiler to benefit from gains in efficiency is not a factor.

I know there is nothing new here but I would really benefit from
changing the focus of the discussion from efficiency to reliabilty and
cost of ownership.

It depends on the point from which one is measuring and projecting and
isn't a simple linear discussion.

On the one hand, if one has a an existing old boiler that is 15 -20
years old and has 60% efficiency then the capital cost is long written
down and the discussion is about the cost in parts of keeping it
running. That one is a fairly simple game of costing. If a failure
is from a thermocouple or perhaps a thermostat, it is probably economic
to continue with it. If a failure is from the heat exchanger or gas
valve, probably not.

On the other hand, if the boiler is a more recent model, it may already
have a 70-75% efficiency and may also not be written down. Then the
replacement of even the more expensive parts may be viable.

One also has to factor in the increasing cost of gas (say 10-15% pa);
although at this point that is still a second order factor - being a
percentage of a percentage.

On that first level, I would agree with you. If a boiler is already
running well and has some lifetime left, and remains servicable
economically, there is no point on a purely financial basis to change it.


There can be other triggers for changing a boiler:

- Change in usage pattern - e.g. more people in the house, building of
an extension

- Original was never up to the job

- Need to relocate the boiler


For me it was a mixture of criteria:

- The old boiler was 15 years old and had had a new thermostat.
There were signs of deterioration from the heat exchanger.

- It was a 65% efficient model and had been written down

- It was necessary to move it owing to a kitchen remodeling

- Additions were being made to the property in terms of a conservatory
and heating for the workshop and it would not have been adequate.

On the basis of these, I felt that there was a fairly clear decision to
replace. Having made that decision, the choice of replacement was
based on build quality, test reports (in my case from Germany), research
of different models and on servicability. I did not decide based on
whether a product was 90 or 91% efficient. As it happened, the model
chosen was at the top end of efficiency at the time (there are others
than are more efficient now but only by about 1%). There was a 5
year parts and labour warranty.

All of that put the purchase price into the top decile of gas boiler
prices among condensing models.

The other thing that I do is to maintain a slush fund for replacement of
domestic equipment. My philosophy for that is to choose only high
quality products - e.g. Miele for white goods and to write the cost down
on a more aggressive basis than the likely lifetime. So for example,
boiler, washing machine, tumble dryer is 10 years. I know that I am
safe with the Miele appliances because the warranty is 10 years. I am
taking a reasonable punt with the boiler. For each year's
contribution to the slush fund, I put in an amount to replace with
something from the top decile of products of the type and add 10% to
that to compensate inflation.
This works pretty well and always remains in "profit".


It would be very hard to find TCO for a boiler based on repair costs.
Manufacturers know what they are funding in terms of spares during
warranty. They also know what they are selling out in terms of spares
after that, plus they know the size of the installed base. Of course,
they won't tell you that. Then there is the issue of generic parts
(although those are generally the low cost ones).

Given all of that, there is not much to go on, other than the common
sense things of looking at build quality - a Viessmann or Vaillant is
better built than a Ravenheat - something obvious to anybody taking the
trouble to research.

Then you can talk to those who actually fix the things independently but
don't have an axe to grind commercially.

In those senses, we do have several people here who give honest opinions
based on their experiences.

I don't think that it gets more scientific than that.



Its so nice to see someone else applying ruthless cost benefit analysis
to home economics.

One point that should be made,and that is the ratio of energy usage to
capital cost.

If energy usage is very high, quite expensive solutions that only
increase efficiency a smidegeun are economically effective.


Another one is reliability: consistently unreliable kit costs money in
terms of the time needed to deal with the problems ..


There is an old axiom of production engineering: What leads to low
productivity is largely *wasted time*. Instead of worrying about making
people work harder, or more effectively,simply watch how often they are
standing idle waiting for something to happen etc, then work out why
thats so and fix it.

If you have to take a day off work to fix a boiler, thats maybe £300 of
holiday time you lost.

Regular servicing is not about the lowest cost of ownership directly,
its about spending fixed predictable sums of money to achieve 100%
uptime :-)

On Sun, 23 Dec 2007 10:28:41 +0000, Andy Hall wrote:

On 2007-12-23 07:02:50 +0000, Edward W. Thompson
said:

On Sat, 22 Dec 2007 10:48:22 +0000, Andy Hall
wrote:

snip
The range of efficiencies of modern condensing boilers is in the range
from 90 - 91.5%.

SEDBUK say that where there are two boilers with 3% difference there
is a 95% confidence that one will be better than the other. They
don't say what the confidence is when the difference is only 0.5% or
1%, but obviously less.
can measurements be made consistently to a fraction of a percent?
Seems unlikely considering the many factors involved.

Consider also the energy cost saving between 90 and 91% (assuming the
figures are reached).

A much more important set of criteria at this point becomes build
quality and servicability.


The discussion on boiler efficiency may be interesting but really is
irrelevant if you accept that the difference of efficiency of modern
boilers will fall within a 10% envelope. For most, I suggest this
equates to something like £50-£60 in their annual gas bill.

On the most recent models it's in about a 3% window allowing fo
rmeasurement uncertainties and the difference in gas bill perhaps around
£15.

As you suggest, in the scheme of things, almost negligible.



If we can
agree that a call out charge for servicing is of the same order, more
if it requires part replacement,cost of repair and servicing are the
more important criteria. I know this has been raised by many but 'we'
still persist with focusing on boiler efficiency.

A call out charge for a service is probably closer to £100.




Further, the cost to replace a boiler, non DIY, is what, something of
the order of £1500 plus? If the reason is purely to benefit from gains
in efficiency and we agree the efficiency of a non condensing boiler is
60%, repayment on cost will be 15 years plus, hardly worth considering.



In my judgement it is economically advantageous to keep a non
condensing boiler in service for as long as economically possible. How
long that is will obviously vary from case to case but to replace a
boiler to benefit from gains in efficiency is not a factor.

I know there is nothing new here but I would really benefit from
changing the focus of the discussion from efficiency to reliabilty and
cost of ownership.

It depends on the point from which one is measuring and projecting and
isn't a simple linear discussion.

On the one hand, if one has a an existing old boiler that is 15 -20
years old and has 60% efficiency then the capital cost is long written
down and the discussion is about the cost in parts of keeping it
running. That one is a fairly simple game of costing. If a failure
is from a thermocouple or perhaps a thermostat, it is probably economic
to continue with it. If a failure is from the heat exchanger or gas
valve, probably not.

On the other hand, if the boiler is a more recent model, it may already
have a 70-75% efficiency and may also not be written down. Then the
replacement of even the more expensive parts may be viable.

One also has to factor in the increasing cost of gas (say 10-15% pa);
although at this point that is still a second order factor - being a
percentage of a percentage.

On that first level, I would agree with you. If a boiler is already
running well and has some lifetime left, and remains servicable
economically, there is no point on a purely financial basis to change
it.


There can be other triggers for changing a boiler:

- Change in usage pattern - e.g. more people in the house, building of
an extension

- Original was never up to the job

- Need to relocate the boiler


For me it was a mixture of criteria:

- The old boiler was 15 years old and had had a new thermostat. There
were signs of deterioration from the heat exchanger.

- It was a 65% efficient model and had been written down

- It was necessary to move it owing to a kitchen remodeling

- Additions were being made to the property in terms of a conservatory
and heating for the workshop and it would not have been adequate.

On the basis of these, I felt that there was a fairly clear decision to
replace. Having made that decision, the choice of replacement was
based on build quality, test reports (in my case from Germany), research
of different models and on servicability. I did not decide based on
whether a product was 90 or 91% efficient. As it happened, the model
chosen was at the top end of efficiency at the time (there are others
than are more efficient now but only by about 1%). There was a 5
year parts and labour warranty.

All of that put the purchase price into the top decile of gas boiler
prices among condensing models.

The other thing that I do is to maintain a slush fund for replacement of
domestic equipment. My philosophy for that is to choose only high
quality products - e.g. Miele for white goods and to write the cost down
on a more aggressive basis than the likely lifetime. So for example,
boiler, washing machine, tumble dryer is 10 years. I know that I am
safe with the Miele appliances because the warranty is 10 years. I am
taking a reasonable punt with the boiler. For each year's
contribution to the slush fund, I put in an amount to replace with
something from the top decile of products of the type and add 10% to
that to compensate inflation.
This works pretty well and always remains in "profit".


It would be very hard to find TCO for a boiler based on repair costs.
Manufacturers know what they are funding in terms of spares during
warranty. They also know what they are selling out in terms of spares
after that, plus they know the size of the installed base. Of course,
they won't tell you that. Then there is the issue of generic parts
(although those are generally the low cost ones).

Given all of that, there is not much to go on, other than the common
sense things of looking at build quality - a Viessmann or Vaillant is
better built than a Ravenheat - something obvious to anybody taking the
trouble to research.

Then you can talk to those who actually fix the things independently but
don't have an axe to grind commercially.

In those senses, we do have several people here who give honest opinions
based on their experiences.

I don't think that it gets more scientific than that.

I second all that Andy has said.

I would also like to point out that the external controls to a heating
system are as significant as the boiler itself. Very often the guiled
claims (there one out from BG at the moment claiming upto 30%) are
incorporating the control system improvements together with the new
boiler. The controls can be upgraded for a fraction of the cost and are
often with the scope of d-i-y for many people. Although the worst case
controls will also require plumbing improvements as well.


--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html

On 23 Dec, 07:02, Edward W. Thompson
wrote:
On Sat, 22 Dec 2007 10:48:22 +0000, Andy Hall
wrote:

snip





The range of efficiencies of modern condensing boilers is in the range
from 90 - 91.5%.

SEDBUK say that where there are two boilers with 3% difference there is
a 95% confidence that one will be better than the other. * They don't
say what the confidence is when the difference is only 0.5% or 1%, but
obviously less.
can measurements be made consistently to a fraction of a percent? *
Seems unlikely considering the many factors involved.

Consider also the energy cost saving between 90 and 91% (assuming the
figures are reached).

A much more important set of criteria at this point becomes build
quality and servicability.

The discussion on boiler efficiency may be interesting but really is
irrelevant if you accept that the difference of efficiency of modern
boilers will fall within a 10% envelope. *For most, I suggest this
equates to something like £50-£60 in their annual gas bill. *If we can
agree that a call out charge for servicing is of the same order, more
if it requires part replacement,cost of repair and servicing are the
more important criteria. *I know this has been raised by many but 'we'
still persist with focusing on boiler efficiency.

Further, the cost to replace a boiler, non DIY, is what, something of
the order of £1500 plus? *If the reason is purely to benefit from
gains in efficiency and we agree the efficiency of a non condensing
boiler is 60%, repayment on cost will be 15 years plus, hardly worth
considering.

In my judgement it is economically advantageous to keep a non
condensing boiler in service for as long as economically possible. How
long that is will obviously vary from case to case but to replace a
boiler to benefit from gains in efficiency is not a factor.

I know there is nothing new here but I would really benefit from
changing the focus of the discussion from efficiency to reliabilty and
cost of ownership.

I think for many modern flats (small, well insulated), whole life COO
is better for electric heating.
For a landlord it is also better (as the LL does not pick up the
energy bills, but does pick up the inspection/service/repair costs).

I used to laugh at marketing people saying that new flats are '"so
well insulated you don't need central heating" as the same thing was
said 30 years ago. But actually I am coming around to that POV. CH
is just too complicated.








- Hide quoted text -

- Show quoted text -

wrote:
On 23 Dec, 07:02, Edward W. Thompson
wrote:
On Sat, 22 Dec 2007 10:48:22 +0000, Andy Hall
wrote:

snip





The range of efficiencies of modern condensing boilers is in the range
from 90 - 91.5%.

SEDBUK say that where there are two boilers with 3% difference there is
a 95% confidence that one will be better than the other. � They don't
say what the confidence is when the difference is only 0.5% or 1%, but
obviously less.
can measurements be made consistently to a fraction of a percent? �
Seems unlikely considering the many factors involved.
Consider also the energy cost saving between 90 and 91% (assuming the
figures are reached).
A much more important set of criteria at this point becomes build
quality and servicability.
The discussion on boiler efficiency may be interesting but really is
irrelevant if you accept that the difference of efficiency of modern
boilers will fall within a 10% envelope. �For most, I suggest this
equates to something like �50-�60 in their annual gas bill. �If we can
agree that a call out charge for servicing is of the same order, more
if it requires part replacement,cost of repair and servicing are the
more important criteria. �I know this has been raised by many but 'we'
still persist with focusing on boiler efficiency.

Further, the cost to replace a boiler, non DIY, is what, something of
the order of �1500 plus? �If the reason is purely to benefit from
gains in efficiency and we agree the efficiency of a non condensing
boiler is 60%, repayment on cost will be 15 years plus, hardly worth
considering.

In my judgement it is economically advantageous to keep a non
condensing boiler in service for as long as economically possible. How
long that is will obviously vary from case to case but to replace a
boiler to benefit from gains in efficiency is not a factor.

I know there is nothing new here but I would really benefit from
changing the focus of the discussion from efficiency to reliabilty and
cost of ownership.

I think for many modern flats (small, well insulated), whole life COO
is better for electric heating.
For a landlord it is also better (as the LL does not pick up the
energy bills, but does pick up the inspection/service/repair costs).

I used to laugh at marketing people saying that new flats are '"so
well insulated you don't need central heating" as the same thing was
said 30 years ago. But actually I am coming around to that POV. CH
is just too complicated.





If you buy the electricity from nuclear power stations it's infinitely
less COO

Sadly its still expensive.
If carbon trading came in, it would instantly become hugely
profitable..Or British Energy could give its carbon coupons to its
shareholders, so they could have big ****off 4WD's ;-)









- Hide quoted text -
- Show quoted text -

"Edward W. Thompson" wrote in message
...

In my judgement

Which is flawed.

it is economically advantageous to keep a non
condensing boiler in service for as long as
economically possible.

You have the assumption that all condensing boilers brake down./ Wrong!!
They do not. Buy a cheapo and they may. Buy quality and they don't.

The difference between the condensing boiler and a non-condensing is
minimal.

In message ews.net,
Doctor Drivel writes

"Edward W. Thompson" wrote in message
.. .

In my judgement

Which is flawed.

it is economically advantageous to keep a non
condensing boiler in service for as long as
economically possible.

You have the assumption that all condensing boilers brake down./

As in break, you mean (the tablets must be wearing off)

Wrong!! They do not. Buy a cheapo and they may. Buy quality and they
don't.

Really?

I don't think so ...


The difference between the condensing boiler and a non-condensing is
minimal.


you mean the "non-" bit ?


--
geoff

The message
from The Natural Philosopher contains these words:

If you buy the electricity from nuclear power stations it's infinitely
less COO

Sadly its still expensive.
If carbon trading came in, it would instantly become hugely
profitable..Or British Energy could give its carbon coupons to its
shareholders, so they could have big ****off 4WD's ;-)

That would be logical but governments in general, and our present sorry
example in particular, don't do logic. If the did they would not have
the face to impose the carbon levy on nuclear as well as on carbon based
fuels.

--
Roger Chapman

"geoff" wrote in message
...
In message ews.net,
Doctor Drivel writes

"Edward W. Thompson" wrote in message
. ..

In my judgement

Which is flawed.

it is economically advantageous to keep a non
condensing boiler in service for as long as
economically possible.

You have the assumption that all condensing boilers brake down./

As in break, you mean (the tablets must be wearing off)

Maxie, you have been on the pop again!!!!

Wrong!! They do not. Buy a cheapo and they may. Buy quality and they
don't.

Really?

I don't think so ...

Maxie, you have been on the pop again!!!!

The difference between the condensing boiler and a non-condensing is
minimal.


you mean the "non-" bit ?

Maxie, you have been on the pop again!!!!

Merry Christmas Maxie. ..and leave the dogs alone!

On 21 Dec, 21:28, wrote:
Thought some of you might like to know the best buys in Which?
Best combis:

Baxi Duo-tec
Potterton Gold
Vaillant ecoTEC
Vaillant ecoTEC(Larger model)

The Baxi and Vaillant were the only two boilers that met the claim of
91% efficiency.

Which is interesting.

The Baxi & the Potterton are made by the same company.

Looking at the installation manuals, the Baxi and the Potterton
mentioned above seem to be the same boiler.
Spot the difference;

http://www.baxi.co.uk/Downloads/Baxi...on%20Guide.pdf

http://www.potterton.co.uk/products/...structions.pdf

In fact, the circular stainless steel heat exchanger in all the above
boiler looks very similar. I think it may be made by Giannoni, or made
under licence from them.

Anyone (excluding Drivel) know more?

On Mon, 24 Dec 2007 08:27:32 -0800, Onetap wrote:

On 21 Dec, 21:28, wrote:
Thought some of you might like to know the best buys in Which? Best
combis:

Baxi Duo-tec
Potterton Gold
Vaillant ecoTEC
Vaillant ecoTEC(Larger model)

The Baxi and Vaillant were the only two boilers that met the claim of
91% efficiency.

Which is interesting.

The Baxi & the Potterton are made by the same company.

Looking at the installation manuals, the Baxi and the Potterton
mentioned above seem to be the same boiler. Spot the difference;

http://www.baxi.co.uk/Downloads/Baxi...%20Combi%20HE%
20Installation%20Guide.pdf

http://www.potterton.co.uk/products/...on-Gold-Combi-
HE-Installation-and-Service-Instructions.pdf


Baxi, Potterton and Main are the same company.

Vaillant and Glow-worm are




--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html

"Onetap" wrote in message
...
On 21 Dec, 21:28, wrote:
Thought some of you might like to know the best buys in Which?
Best combis:

Baxi Duo-tec
Potterton Gold
Vaillant ecoTEC
Vaillant ecoTEC(Larger model)

The Baxi and Vaillant were the only two boilers that met the claim of
91% efficiency.

Which is interesting.

The Baxi & the Potterton are made by the same company.

Looking at the installation manuals, the Baxi and the Potterton
mentioned above seem to be the same boiler.
Spot the difference;

http://www.baxi.co.uk/Downloads/Baxi...on%20Guide.pdf

http://www.potterton.co.uk/products/...structions.pdf

In fact, the circular stainless steel heat exchanger in all the above
boiler looks very similar. I think it may be made by Giannoni, or made
under licence from them.

Anyone (excluding Drivel) know more?

Of course they don't.

On Mon, 24 Dec 2007 08:27:32 -0800, Onetap wrote:

The Baxi & the Potterton are made by the same company.
....
In fact, the circular stainless steel heat exchanger in all the above
boiler looks very similar. I think it may be made by Giannoni, or made
under licence from them.

There was a post-mortem of one of these on Gas News earlier this year,
which criticised some aspects of its design such as the
potential for a vertically mounted coil of tube to accumulate sediment at
the bottom of the turns, and the impossibility of flushing out a blockage
in one passageway plumbed in parallel with others:

http://www.gas-news.co.uk/archive/st...mment/1006.htm

--
John Stumbles

"John Stumbles" wrote in message
...
On Mon, 24 Dec 2007 08:27:32 -0800, Onetap wrote:

The Baxi & the Potterton are made by the same company.
...
In fact, the circular stainless steel
heat exchanger in all the above
boiler looks very similar. I think it
may be made by Giannoni, or made
under licence from them.

There was a post-mortem of one of these on Gas News earlier this year,
which criticised some aspects of its design such as the
potential for a vertically mounted coil of tube to accumulate sediment at
the bottom of the turns, and the impossibility of flushing out a blockage
in one passageway plumbed in parallel with others:

http://www.gas-news.co.uk/archive/st...mment/1006.htm

These Giannoni heat exchangers are plentiful and are in millions of boilers.
Even Heatline, BIASI and Ravenheat have models using this heat exchanger.
They work OK indeed and have been around for quite a while. They are a
horizontal coil of stainless steel with the burner horizontal too. I prefer
the Keston vertically coiled heat exchangers with the burner on the top and
the flue outlet at the bottom. The condensate washes down the heat
exchanger cleaning it as it burns. The Keston Qudos is now a highly cost
effective well designed boiler offering high functionality too. This Qudos
boiler must be assessed when buying a boiler. Reliability is not yet proven
though, although most parts are taken from reliable Keston models, so should
be fine

I personally like the Atmos heat exchangers. It is whole of the boilers
back panel. The height and width of the boiler. This design uses all space
available and makes for a smaller boiler too. They are also very well made
of thick gauge copper too. The combi version just has a coil of copper tube
run through the heat exchanger and acts like a conventional multi-point
water heater when generating DHW. Have a look:

Look at the space inside the Atmos Intergas boiler for burner and pump.
Amazing!
http://www.atmos.uk.com/product_group.asp?section=000200130003

This shows the inside of the Atmos heat exchanger:
http://www.atmos.uk.com/core_files/productDoc(136).pdf

"John Stumbles" wrote in message
...
On Mon, 24 Dec 2007 08:27:32 -0800, Onetap wrote:

The Baxi & the Potterton are made by the same company.
...
In fact, the circular stainless steel heat exchanger in all the above
boiler looks very similar. I think it may be made by Giannoni, or made
under licence from them.

There was a post-mortem of one of these on Gas News earlier this year,
which criticised some aspects of its design such as the
potential for a vertically mounted coil of tube to accumulate sediment at
the bottom of the turns, and the impossibility of flushing out a blockage
in one passageway plumbed in parallel with others:

http://www.gas-news.co.uk/archive/st...mment/1006.htm



The Giannoni heat exchangers:
http://www.giannoni.fr/Prod-ABSOLUT-CONDENS.html

On Sat, 29 Dec 2007 13:58:22 +0000, Doctor Drivel wrote:

These Giannoni heat exchangers are plentiful and are in millions of boilers.
Even Heatline, BIASI and Ravenheat have models using this heat exchanger.

Dunno about Heatline but saying "even" BIASI and Ravenheat use this HX is
like saying even Poundshop and Costcutter stock a product: it says cheap
tat not high quality.

--
John Stumbles

Pessimists are never disappointed

On Sat, 29 Dec 2007 14:50:18 +0000, Doctor Drivel wrote:

"John Stumbles" wrote
http://www.gas-news.co.uk/archive/st...mment/1006.htm

The Giannoni heat exchangers:
http://www.giannoni.fr/Prod-ABSOLUT-CONDENS.html

That's just a product brochu it doesn't answer the concerns and
criticisms raised in the GN article.

--
John Stumbles

The floggings will continue until morale improves