I have just had my loft timbers/joists treated for woodworm, and getting
the house rewired soon. After that is all done, I am going to put
insulation down. However I have some questions about it.

Is there a noticable difference in loft insulation (rockwool rolls) in
insulating greater than a 4" depth? The reason I ask is that my joists
are 4" in height, and anything greater will mean a bit more planning to
ensure that I can still walk and see the joists up there.

Also, has anyone noticed a difference between rockwool and other types,
such as crown wool? I have checked the u-values and such, and rockwool is
a better insulator, but it is also going to cost me about 20% more than
crown insulation. (b&q special offer).

I really like the idea of using natural insulation such as sheep wool :
(http://www.greenbuildingstore.co.uk/ins-thermperf.php) but the price is
unbelievable.

Any comments/help/advice would be greatly received.

Thanks.

Is there a noticable difference in loft insulation (rockwool rolls) in
insulating greater than a 4" depth?

Yes. The law of diminishing returns says that 350mm is the best
environmentally speaking. Any more and the environmental cost of
manufacturing and transporting the insulant is higher than the energy saved.
100mm is definitely on the low side. 200mm would be better. The difference
between 200mm and 350mm isn't that great.

Christian.

Dean Richard Benson wrote:
I have just had my loft timbers/joists treated for woodworm, and getting
the house rewired soon. After that is all done, I am going to put
insulation down. However I have some questions about it.

Is there a noticable difference in loft insulation (rockwool rolls) in
insulating greater than a 4" depth? The reason I ask is that my joists
are 4" in height, and anything greater will mean a bit more planning to
ensure that I can still walk and see the joists up there.

Also, has anyone noticed a difference between rockwool and other types,
such as crown wool? I have checked the u-values and such, and rockwool is
a better insulator, but it is also going to cost me about 20% more than
crown insulation. (b&q special offer).

I really like the idea of using natural insulation such as sheep wool :
(http://www.greenbuildingstore.co.uk/ins-thermperf.php) but the price is
unbelievable.

Any comments/help/advice would be greatly received.

Thanks.


why not use this http://stardust.jpl.nasa.gov/tech/aerogel.html stuff?
OK it's a bit expensive ($11/gram) but hey, when you want the best. . . .
'It's the lowest density of any solid, and it has the highest
thermoinsulation properties. Though it would be very expensive, you
could take a two- or three-bedroom house, insulate it with aerogel, and
you could heat the house with a candle. But eventually the house would
become too hot.'"

Nick

On Wed, 21 Jan 2004 16:29:12 +0000, Christian McArdle wrote:

Yes. The law of diminishing returns says that 350mm is the best
environmentally speaking. Any more and the environmental cost of
manufacturing and transporting the insulant is higher than the energy saved.
100mm is definitely on the low side. 200mm would be better. The difference
between 200mm and 350mm isn't that great.

Some useful info in there. Leads me to even more questions....

- with currently having a 100mm joist height, should i either increase the
joist height (cross joists) or just cross-lay the insulation over the top
of the 100mm.

- If you insulation up to 350mm, how are you meant to ever reach places in
your loft without falling through the ceiling ;P

- You mention the recommended above, based on diminishing returns, but
what insulation material is that based on - as I understand it, different
manufacturers produce insulation to different values. So my thought was,
that maybe 200mm of rockwool, might equal 300mm of crown or something?

Thanks again

Dean

On Wed, 21 Jan 2004 16:16:10 +0000, Dean Richard Benson
wrote:

I have just had my loft timbers/joists treated for woodworm, and getting
the house rewired soon. After that is all done, I am going to put
insulation down. However I have some questions about it.

Is there a noticable difference in loft insulation (rockwool rolls) in
insulating greater than a 4" depth? The reason I ask is that my joists
are 4" in height, and anything greater will mean a bit more planning to
ensure that I can still walk and see the joists up there.

Also, has anyone noticed a difference between rockwool and other types,
such as crown wool? I have checked the u-values and such, and rockwool is
a better insulator, but it is also going to cost me about 20% more than
crown insulation. (b&q special offer).

I really like the idea of using natural insulation such as sheep wool :
(http://www.greenbuildingstore.co.uk/ins-thermperf.php) but the price is
unbelievable.

Any comments/help/advice would be greatly received.

Thanks.

You can do the sums on this.

Calculate the heat loss for the area of the ceilings.

For a pitched roof plus 100mm of insulation, the U value is 0.35

So, let's say the house is 7m square for the sake of argument.

Using conventional central heating temperature assumptions of -3
degrees worst case outside and 18 degrees in the upstairs rooms, the
heat loss will be

Area x U x temperature difference

or 7 x 7 x 21 x 0.35 = 360 Watts

If you have 150mm of insulation, the U value falls to 0.25 and the
heat loss will be 257W.

With no insulation, the U value of the pitched roof is about 2.0 and
the heat loss about 2kW.

You can see that there is a huge difference between nothing and 100mm,
but a rapidly diminishing return after that.

This is typical worst case.

However, averaged over the year, the outside temperature is probably
closer to 10 degrees, so assuming continuous heating at 100mm of
insulation the loss is 223Watts and at 150mm about 160W. With 200mm
you would get down towards 120W.

100W of heating by gas at a price of 1.4p per kWh works out to just
over £12 per annum.

In terms of the material cost, this provides a reasonable rate of
return. However, if you set it in the context of whether the space
is important to you and the cost of the timber and other means to
access it, then this becomes less interesting.

In energy terms, if you compare with the heat loss through the walls
and other means, then you realise that the focus should be on other
issues than this.







..andy

To email, substitute .nospam with .gl

Dean Richard Benson wrote in
news

Is there a noticable difference in loft insulation (rockwool rolls) in
insulating greater than a 4" depth? The reason I ask is that my
joists are 4" in height, and anything greater will mean a bit more
planning to ensure that I can still walk and see the joists up there.

Can't answer quantitatively, but for the same reason I put down 4inches
(HTF does one cope with a foot of insulation?)

It's made a big difference, there was already a skimpy fibregass layer
there, but it's pretty well just the 4 ins.

So I think I would stick with 4 ins ant take the losses, at least I can
still find joists, wiring, pipes, chimneys etc.

mike r

On Wed, 21 Jan 2004 18:28:07 +0000, Dean Richard Benson
wrote:

On Wed, 21 Jan 2004 16:29:12 +0000, Christian McArdle wrote:

Yes. The law of diminishing returns says that 350mm is the best
environmentally speaking. Any more and the environmental cost of
manufacturing and transporting the insulant is higher than the energy saved.
100mm is definitely on the low side. 200mm would be better. The difference
between 200mm and 350mm isn't that great.

Some useful info in there. Leads me to even more questions....

- with currently having a 100mm joist height, should i either increase the
joist height (cross joists) or just cross-lay the insulation over the top
of the 100mm.

It depends on whether you want to board over the top.


- If you insulation up to 350mm, how are you meant to ever reach places in
your loft without falling through the ceiling ;P

It may not matter, since you won't be putting many other things there
anyway :-)

Before you get over-excited by this idea, take a look at how much heat
is going out through the walls and windows.......



- You mention the recommended above, based on diminishing returns, but
what insulation material is that based on - as I understand it, different
manufacturers produce insulation to different values. So my thought was,
that maybe 200mm of rockwool, might equal 300mm of crown or something?

If you want a better compromise between thickness and U value, then
you could use polyisosyanurate board such as Celotex or Kingspan which
have about 4x the insulating property of glass fibre.

However, it costs £15-18 for a 2440x1220 sheet........



Thanks again

Dean

..andy

To email, substitute .nospam with .gl

Andy Hall wrote:

On Wed, 21 Jan 2004 18:28:07 +0000, Dean Richard Benson
wrote:


On Wed, 21 Jan 2004 16:29:12 +0000, Christian McArdle wrote:


Yes. The law of diminishing returns says that 350mm is the best
environmentally speaking. Any more and the environmental cost of
manufacturing and transporting the insulant is higher than the energy saved.
100mm is definitely on the low side. 200mm would be better. The difference
between 200mm and 350mm isn't that great.

Some useful info in there. Leads me to even more questions....

- with currently having a 100mm joist height, should i either increase the
joist height (cross joists) or just cross-lay the insulation over the top
of the 100mm.


It depends on whether you want to board over the top.


- If you insulation up to 350mm, how are you meant to ever reach places in
your loft without falling through the ceiling ;P


It may not matter, since you won't be putting many other things there
anyway :-)


Ah, but never underestimate the insulatng properties of a loft full of
junk :-)



Before you get over-excited by this idea, take a look at how much heat
is going out through the walls and windows.......




Indeed.

Andy Hall wrote in
:


You can do the sums on this.

No, I can't, you do them

Calculate the heat loss for the area of the ceilings.

For a pitched roof plus 100mm of insulation, the U value is 0.35

So, let's say the house is 7m square for the sake of argument.

Using conventional central heating temperature assumptions of -3
degrees worst case outside and 18 degrees in the upstairs rooms, the
heat loss will be

Area x U x temperature difference

or 7 x 7 x 21 x 0.35 = 360 Watts

If you have 150mm of insulation, the U value falls to 0.25 and the
heat loss will be 257W.

With no insulation, the U value of the pitched roof is about 2.0 and
the heat loss about 2kW.

Ta

However, averaged over the year, the outside temperature is probably
closer to 10 degrees, so assuming continuous heating at 100mm of
insulation the loss is 223Watts and at 150mm about 160W. With 200mm
you would get down towards 120W.

100W of heating by gas at a price of 1.4p per kWh works out to just
over £12 per annum.

In energy terms, if you compare with the heat loss through the walls
and other means, then you realise that the focus should be on other
issues than this.

Thanks Andy, you've confirmed my gut feeling about losses, and also that
one episode of tripping over a pipe and putting a foot through the
ceiling will take a hell of a time to balance against the extra 8"
insulation.

mike r

"Christian McArdle" wrote in message
et...
Is there a noticable difference in loft insulation (rockwool rolls) in
insulating greater than a 4" depth?

Yes. The law of diminishing returns says that 350mm is the best
environmentally speaking. Any more and the environmental cost of
manufacturing and transporting the insulant is higher than the energy
saved.
100mm is definitely on the low side. 200mm would be better. The difference
between 200mm and 350mm isn't that great.

Are you sure on this. It's just I heard the ODPM people who set the
building regs were talking about as much as 450mm in the next part L.

Rockwool is on 3 for the price of 2 at Wickes and so matches the B&Q prices
well.

On Thu, 22 Jan 2004 00:02:57 -0000, "G&M" wrote:


"Christian McArdle" wrote in message
. net...
Is there a noticable difference in loft insulation (rockwool rolls) in
insulating greater than a 4" depth?

Yes. The law of diminishing returns says that 350mm is the best
environmentally speaking. Any more and the environmental cost of
manufacturing and transporting the insulant is higher than the energy
saved.
100mm is definitely on the low side. 200mm would be better. The difference
between 200mm and 350mm isn't that great.

Are you sure on this. It's just I heard the ODPM people who set the
building regs were talking about as much as 450mm in the next part L.

They talk about all sorts of things. This one is pure pandering to
be seen to be doing something towards the Kyoto protocol. It has no
basis in economics or anything else when put into the context of where
domestic energy should be being saved.

So people in an average house can spend about £100-200 and save about
£10 a year.

It's a complete nonsense.



Rockwool is on 3 for the price of 2 at Wickes and so matches the B&Q prices
well.


..andy

To email, substitute .nospam with .gl

"Andy Hall" wrote in message
...
On Thu, 22 Jan 2004 00:02:57 -0000, "G&M" wrote:

"Christian McArdle" wrote in message
. net...
Is there a noticable difference in loft insulation (rockwool rolls)
in
insulating greater than a 4" depth?

Yes. The law of diminishing returns says that 350mm is the best
environmentally speaking. Any more and the environmental cost of
manufacturing and transporting the insulant is higher than the energy
saved.
100mm is definitely on the low side. 200mm would be better. The
difference
between 200mm and 350mm isn't that great.

Are you sure on this. It's just I heard the ODPM people who set the
building regs were talking about as much as 450mm in the next part L.

They talk about all sorts of things. This one is pure pandering to
be seen to be doing something towards the Kyoto protocol. It has no
basis in economics or anything else when put into the context of where
domestic energy should be being saved.

This is ********! The Whole House Book has a graph that says 350-400mm is
the current optimum price/performance. If fuel rises, which it will as
cheap energy is coming to an end, then this is meaningless and 450-500mm is
the optimum. Ecohouse - A Design Guide says there is no upper limit to
insulation, as it will pay for itself eventually. There is also the comfort
factor of high insulation and that it also keeps the house cool from a loft
hat may be 55C in summer.


---
--

Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.561 / Virus Database: 353 - Release Date: 14/01/2004

"Andy Hall" wrote in message
...
On Wed, 21 Jan 2004 16:16:10 +0000, Dean Richard Benson
wrote:

I have just had my loft timbers/joists treated for woodworm, and getting
the house rewired soon. After that is all done, I am going to put
insulation down. However I have some questions about it.

Is there a noticable difference in loft insulation (rockwool rolls) in
insulating greater than a 4" depth? The reason I ask is that my joists
are 4" in height, and anything greater will mean a bit more planning to
ensure that I can still walk and see the joists up there.

Also, has anyone noticed a difference between rockwool and other types,
such as crown wool? I have checked the u-values and such, and rockwool
is
a better insulator, but it is also going to cost me about 20% more than
crown insulation. (b&q special offer).

I really like the idea of using natural insulation such as sheep wool :
(http://www.greenbuildingstore.co.uk/ins-thermperf.php) but the price is
unbelievable.

Any comments/help/advice would be greatly received.

Thanks.

You can do the sums on this.

Calculate the heat loss for the area of the ceilings.

For a pitched roof plus 100mm of insulation, the U value is 0.35

So, let's say the house is 7m square for the sake of argument.

Using conventional central heating temperature assumptions of -3
degrees worst case outside and 18 degrees in the upstairs rooms, the
heat loss will be

Area x U x temperature difference

or 7 x 7 x 21 x 0.35 = 360 Watts

If you have 150mm of insulation, the U value falls to 0.25 and the
heat loss will be 257W.

With no insulation, the U value of the pitched roof is about 2.0 and
the heat loss about 2kW.

You can see that there is a huge difference between nothing and 100mm,
but a rapidly diminishing return after that.

This is typical worst case.

However, averaged over the year, the outside temperature is probably
closer to 10 degrees, so assuming continuous heating at 100mm of
insulation the loss is 223Watts and at 150mm about 160W. With 200mm
you would get down towards 120W.

100W of heating by gas at a price of 1.4p per kWh works out to just
over £12 per annum.

In terms of the material cost, this provides a reasonable rate of
return. However, if you set it in the context of whether the space
is important to you and the cost of the timber and other means to
access it, then this becomes less interesting.

In energy terms, if you compare with the heat loss through the walls
and other means, then you realise that the focus should be on other
issues than this.

How mixed up you are. Overall the walls loose more heat than the upper
ceilingof a house. That is misleading. Then look at the individual rooms
below the loft. They will have a large area which is loft ceiling. Then it
makes sense to heavily insulate, as these rooms will be warm in winter and
cool in summer. In August the coolest place in my house was the main
bedroom. No heat came down from the loft above as I have 350mm of
insulation. A light wind through the two windows and it was fine in the
upper rooms. In winter they are very warm.

And you said a uni made you think?





---
--

Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.561 / Virus Database: 353 - Release Date: 14/01/2004

"mike ring" wrote in message
52.50...
Andy Hall wrote in
:


You can do the sums on this.

No, I can't, you do them

Calculate the heat loss for the area of the ceilings.

For a pitched roof plus 100mm of insulation, the U value is 0.35

So, let's say the house is 7m square for the sake of argument.

Using conventional central heating temperature assumptions of -3
degrees worst case outside and 18 degrees in the upstairs rooms, the
heat loss will be

Area x U x temperature difference

or 7 x 7 x 21 x 0.35 = 360 Watts

If you have 150mm of insulation, the U value falls to 0.25 and the
heat loss will be 257W.

With no insulation, the U value of the pitched roof is about 2.0 and
the heat loss about 2kW.

Ta

However, averaged over the year, the outside temperature is probably
closer to 10 degrees, so assuming continuous heating at 100mm of
insulation the loss is 223Watts and at 150mm about 160W. With 200mm
you would get down towards 120W.

100W of heating by gas at a price of 1.4p per kWh works out to just
over £12 per annum.

In energy terms, if you compare with the heat loss through the walls
and other means, then you realise that the focus should be on other
issues than this.

Thanks Andy, you've confirmed my gut feeling about losses, and also that
one episode of tripping over a pipe and putting a foot through the
ceiling will take a hell of a time to balance against the extra 8"
insulation.

Put counter joists in to make it deeper for more insulation and board over.


---
--

Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.561 / Virus Database: 353 - Release Date: 14/01/2004

On Thu, 22 Jan 2004 00:59:39 -0000, "IMM" wrote:

"Andy Hall" wrote in message
.. .
On Thu, 22 Jan 2004 00:02:57 -0000, "G&M" wrote:

"Christian McArdle" wrote in message
. net...
Is there a noticable difference in loft insulation (rockwool rolls)
in
insulating greater than a 4" depth?

Yes. The law of diminishing returns says that 350mm is the best
environmentally speaking. Any more and the environmental cost of
manufacturing and transporting the insulant is higher than the energy
saved.
100mm is definitely on the low side. 200mm would be better. The
difference
between 200mm and 350mm isn't that great.

Are you sure on this. It's just I heard the ODPM people who set the
building regs were talking about as much as 450mm in the next part L.

They talk about all sorts of things. This one is pure pandering to
be seen to be doing something towards the Kyoto protocol. It has no
basis in economics or anything else when put into the context of where
domestic energy should be being saved.

This is ********!

You're absolutely right. It is total ******** and political game
playing.


The Whole House Book has a graph that says 350-400mm is
the current optimum price/performance.

Based on what? Show the calculations. I wasn't talking about the
total environmental cost or anything of that nature, just very simple
economics of

a) what is the heat loss with insulation thickness X?
b) what is it with thickness Y?
c) what's the energy saving and what does that cost at today's prices?
d) what does it cost to install insulation to achieve that?

Based on the hard figures and those assumptions *only* please explain
where you feel that there is a mistake in the numbers.


If fuel rises, which it will as
cheap energy is coming to an end, then this is meaningless and 450-500mm is
the optimum.

That's a separate issue. Can you suggest a rate at which fuel
prices would need to rise to justify that?

Even if energy loss through the roof were reduced to zero by going to
the ridiculous lengths that you are suggesting, if the walls and
window losses are not reduced then the difference made is worthless.

Keep in mind that the topic here was concerning the value *today* and
in the near future of increasing loft insulation.
In terms of return on investment, it may be interesting to do because
it is inexpensive, but then the returns are relatively little as well.

My point was that focussing on this, while ignoring other much more
significant losses is the wrong focus. There is not much point in
saving £10 a year on what goes through the roof if £200 is going
through other surfaces. Even if energy goes up in price by a
factor of ten, that principle still applies. All that changes is the
urgency and the economics not the priority.



Ecohouse - A Design Guide says there is no upper limit to
insulation, as it will pay for itself eventually.

It's very easy to sit down and write airy-fairy books when it's other
people's money being spent. Almost anything pays for itself
*eventually* - that's a very weak argument.

There is also the comfort
factor of high insulation and that it also keeps the house cool from a loft
hat may be 55C in summer.

Having any insulation will do that. It doesn't need to be knee deep
to achieve it. Do the sums. The temperature differences put the
heat gain in the low hundreds of watts over an entire house even with
just 100mm of glass fibre. On a room by room basis, not much more
than a light bulb.

If people in government and elsewhere want to advocate that homeowners
should put more insulation in their roofs, that's fine - as you say
it's cheap and easy. However the *complete* picture, including the
economics and the comparisons with other energy saving should be
presented and it is not. The reality is that the government wants
to demonstrate in the international conference scene that it is doing
something with respect to Kyoto. There is nothing wrong with the
sentiment of that, but it should be done on an honest basis, and this
is not.






---

..andy

To email, substitute .nospam with .gl

On Thu, 22 Jan 2004 01:15:45 -0000, "IMM" wrote:


"mike ring" wrote in message
. 252.50...
Andy Hall wrote in
:


You can do the sums on this.

No, I can't, you do them

Calculate the heat loss for the area of the ceilings.

For a pitched roof plus 100mm of insulation, the U value is 0.35

So, let's say the house is 7m square for the sake of argument.

Using conventional central heating temperature assumptions of -3
degrees worst case outside and 18 degrees in the upstairs rooms, the
heat loss will be

Area x U x temperature difference

or 7 x 7 x 21 x 0.35 = 360 Watts

If you have 150mm of insulation, the U value falls to 0.25 and the
heat loss will be 257W.

With no insulation, the U value of the pitched roof is about 2.0 and
the heat loss about 2kW.

Ta

However, averaged over the year, the outside temperature is probably
closer to 10 degrees, so assuming continuous heating at 100mm of
insulation the loss is 223Watts and at 150mm about 160W. With 200mm
you would get down towards 120W.

100W of heating by gas at a price of 1.4p per kWh works out to just
over £12 per annum.

In energy terms, if you compare with the heat loss through the walls
and other means, then you realise that the focus should be on other
issues than this.

Thanks Andy, you've confirmed my gut feeling about losses, and also that
one episode of tripping over a pipe and putting a foot through the
ceiling will take a hell of a time to balance against the extra 8"
insulation.

Put counter joists in to make it deeper for more insulation and board over.

Why? In comparison to everything else, it's little more than a drop
in the bucket.


---

..andy

To email, substitute .nospam with .gl

On Thu, 22 Jan 2004 01:13:58 -0000, "IMM" wrote:


"Andy Hall" wrote in message
.. .


100W of heating by gas at a price of 1.4p per kWh works out to just
over £12 per annum.

In terms of the material cost, this provides a reasonable rate of
return. However, if you set it in the context of whether the space
is important to you and the cost of the timber and other means to
access it, then this becomes less interesting.

In energy terms, if you compare with the heat loss through the walls
and other means, then you realise that the focus should be on other
issues than this.

How mixed up you are. Overall the walls loose more heat than the upper
ceilingof a house.

Obviously. The area is generally larger and the U value greater or
comparable to 100mm of loft insulation


That is misleading. Then look at the individual rooms
below the loft. They will have a large area which is loft ceiling.

They will have a large area of walls and windows as well.

Then it
makes sense to heavily insulate, as these rooms will be warm in winter and
cool in summer.

That doesn't follow at all.


In August the coolest place in my house was the main
bedroom. No heat came down from the loft above as I have 350mm of
insulation.

That doesn't follow either.

Provide the dimensions of the room including the windows and the
construction type of the walls and windows and we can do the sums.

I would be very surprised if the difference in heat gain that you
experience through having 350mm of insulation vs. 100 or 150mm is
significant in comparison to gains through other surfaces.




A light wind through the two windows and it was fine in the
upper rooms. In winter they are very warm.

And you said a uni made you think?

Yes it does, as well as the ability to spot bull**** when I see it.






---

..andy

To email, substitute .nospam with .gl

Thanks Andy, you've confirmed my gut feeling about losses, and also
that one episode of tripping over a pipe and putting a foot through
the ceiling will take a hell of a time to balance against the extra 8"
insulation.

Consider using Kingspan or Celotex. Although more expensive that rockwool,
100mm will give a lot more insulation that rockwool. It is also longer
lasting and less prone to sagging and soaking, as it comes in solid blocks
looking a bit like expanded polystyrene. You can board straight over the
top.

Christian.

"Andy Hall" wrote in message
...
On Thu, 22 Jan 2004 00:59:39 -0000, "IMM" wrote:

"Andy Hall" wrote in message
.. .
On Thu, 22 Jan 2004 00:02:57 -0000, "G&M" wrote:

"Christian McArdle" wrote in
message
. net...
Is there a noticable difference in loft insulation (rockwool
rolls)
in
insulating greater than a 4" depth?

Yes. The law of diminishing returns says that 350mm is the best
environmentally speaking. Any more and the environmental cost of
manufacturing and transporting the insulant is higher than the
energy
saved.
100mm is definitely on the low side. 200mm would be better. The
difference
between 200mm and 350mm isn't that great.

Are you sure on this. It's just I heard the ODPM people who set the
building regs were talking about as much as 450mm in the next part L.

They talk about all sorts of things. This one is pure pandering to
be seen to be doing something towards the Kyoto protocol. It has no
basis in economics or anything else when put into the context of where
domestic energy should be being saved.

This is ********!

You're absolutely right. It is total ******** and political game
playing.

The Whole House Book has a graph that says 350-400mm is
the current optimum price/performance.

Based on what? Show the calculations. I wasn't talking about the
total environmental cost or anything of that nature, just very simple
economics of

a) what is the heat loss with insulation thickness X?
b) what is it with thickness Y?
c) what's the energy saving and what does that cost at today's prices?
d) what does it cost to install insulation to achieve that?

That is what the Whole House Book did.

If fuel rises, which it will as
cheap energy is coming to an end, then this is meaningless and 450-500mm
is
the optimum.

That's a separate issue. Can you suggest a rate at which fuel
prices would need to rise to justify that?

Hold a fdiger to the air. Fuel porices will rise. They always do. Also
enviro taxes will start to bite.

Even if energy loss through the roof were reduced to zero by going to
the ridiculous lengths that you are suggesting,

I'm nor suggesting it. People who have done the research are.

if the walls and
window losses are not reduced then the difference made is worthless.

Keep in mind that the topic here was concerning the value *today* and
in the near future of increasing loft insulation.

Near future? What will that be? Ermmm...

In terms of return on investment, it may be interesting to do because
it is inexpensive, but then the returns are relatively little as well.

Loft insulation is cheap and very easy to do compared to other parts of the
house. So it is worth packing in as much as possible.

My point was that focussing on this, while ignoring other much more
significant losses is the wrong focus. There is not much point in
saving £10 a year on what goes through the roof if £200 is going
through other surfaces. Even if energy goes up in price by a
factor of ten, that principle still applies. All that changes is the
urgency and the economics not the priority.

Ecohouse - A Design Guide says there is no upper limit to
insulation, as it will pay for itself eventually.

It's very easy to sit down and write airy-fairy books when it's other
people's money being spent. Almost anything pays for itself
*eventually* - that's a very weak argument.

In the book EcoHouse - A Design Guide, they gave a study that calculated in
1987 200mm was the optimum in walls at the then current fuel prices.

As fuel prices rise and the insulation manufacturing costs too, the whole
payback calcs were skewed somewhat. So they calculated insulation levels on
energy to make insulation. They came to the thickness of 650mm. The
conclusion was that what constrains you is the detailing of the structure to
hold as much insulation as possible. So, install as much as possible.

There is also the comfort
factor of high insulation and that it also keeps the house cool from a
loft
hat may be 55C in summer.

Having any insulation will do that. It doesn't need to be knee deep
to achieve it.

The bigger the temp difference on each side and the bigger the heat
transfer. More insulation prevents heat transfer.

If people in government and elsewhere want to advocate that homeowners
should put more insulation in their roofs, that's fine - as you say
it's cheap and easy.

snip misguided stuff about economics.


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"Andy Hall" wrote in message
...
On Thu, 22 Jan 2004 01:15:45 -0000, "IMM" wrote:


"mike ring" wrote in message
. 252.50...
Andy Hall wrote in
:


You can do the sums on this.

No, I can't, you do them

Calculate the heat loss for the area of the ceilings.

For a pitched roof plus 100mm of insulation, the U value is 0.35

So, let's say the house is 7m square for the sake of argument.

Using conventional central heating temperature assumptions of -3
degrees worst case outside and 18 degrees in the upstairs rooms, the
heat loss will be

Area x U x temperature difference

or 7 x 7 x 21 x 0.35 = 360 Watts

If you have 150mm of insulation, the U value falls to 0.25 and the
heat loss will be 257W.

With no insulation, the U value of the pitched roof is about 2.0 and
the heat loss about 2kW.

Ta

However, averaged over the year, the outside temperature is probably
closer to 10 degrees, so assuming continuous heating at 100mm of
insulation the loss is 223Watts and at 150mm about 160W. With 200mm
you would get down towards 120W.

100W of heating by gas at a price of 1.4p per kWh works out to just
over £12 per annum.

In energy terms, if you compare with the heat loss through the walls
and other means, then you realise that the focus should be on other
issues than this.

Thanks Andy, you've confirmed my gut feeling about losses, and also
that
one episode of tripping over a pipe and putting a foot through the
ceiling will take a hell of a time to balance against the extra 8"
insulation.

Put counter joists in to make it deeper for more insulation and board
over.

Why? In comparison to everything else, it's little more than a drop
in the bucket.

Not so. read other post.


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"Christian McArdle" wrote in message
et...
Thanks Andy, you've confirmed my gut feeling about losses, and also
that one episode of tripping over a pipe and putting a foot through
the ceiling will take a hell of a time to balance against the extra 8"
insulation.

Consider using Kingspan or Celotex. Although more expensive that rockwool,
100mm will give a lot more insulation that rockwool. It is also longer
lasting and less prone to sagging and soaking, as it comes in solid blocks
looking a bit like expanded polystyrene. You can board straight over the
top.

Best put Rockwool up to joist height then lay Kingspan over then loft
boards.


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"Andy Hall" wrote in message
...
On Thu, 22 Jan 2004 01:13:58 -0000, "IMM" wrote:


"Andy Hall" wrote in message
.. .


100W of heating by gas at a price of 1.4p per kWh works out to just
over £12 per annum.

In terms of the material cost, this provides a reasonable rate of
return. However, if you set it in the context of whether the space
is important to you and the cost of the timber and other means to
access it, then this becomes less interesting.

In energy terms, if you compare with the heat loss through the walls
and other means, then you realise that the focus should be on other
issues than this.

How mixed up you are. Overall the walls loose more heat than the upper
ceilingof a house.

Obviously. The area is generally larger and the U value greater or
comparable to 100mm of loft insulation


That is misleading. Then look at the individual rooms
below the loft. They will have a large area which is loft ceiling.

They will have a large area of walls and windows as well.

Bt what you have failed to see, is that these rooms have a large percentage
of ceiling area. A ceiling that will be very cold above in winter and very
hot in summer. It is worth packing in as much insulation as possible just
to improve the comfort levels of these rooms alone.

Then it
makes sense to heavily insulate, as these rooms will be warm in winter
and
cool in summer.

That doesn't follow at all.

See above twice.

In August the coolest place in my house was the main
bedroom. No heat came down from the loft above as I have 350mm of
insulation.

That doesn't follow either.

snip. He can't follow something simple, not worth going on



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Best put Rockwool up to joist height then lay Kingspan over then loft
boards.

Which doesn't give the OP his required boarded area. If he was going to
cover the boards, he might as well use rockwool, as it is better pricewise
for the same u-Value.

Christian.

"Christian McArdle" wrote in message
et...

Best put Rockwool up to joist height then lay Kingspan over then loft
boards.

Which doesn't give the OP his required boarded area. If he was going to
cover the boards, he might as well use rockwool, as it is better pricewise
for the same u-Value.

I think you misunderstood. Best put Rockwool up to joist height then lay
Kingspan over the joists, this prevents thermal bridging via the joists.
Then loft boards over the Kingspan. Only the part of the loft where you can
walk is worth boarding, unless all the loft is used for storage.



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Andy Hall wrote:


Even if energy loss through the roof were reduced to zero by going to
the ridiculous lengths that you are suggesting, if the walls and
window losses are not reduced then the difference made is worthless.


IMM's uni only taught him about straight lines and binary thinking.

Its no good talking to him about curves and maxima/minima.

The only curves he ever takes notice of, are on page 3.

And when he switched to the socialist worker, he lost track of even those.

"The Natural Philosopher" wrote in message
...
Andy Hall wrote:


Even if energy loss through the roof were reduced to zero by going to
the ridiculous lengths that you are suggesting, if the walls and
window losses are not reduced then the difference made is worthless.


IMM's uni only taught him about straight lines and binary thinking.

Its no good talking to him about curves and maxima/minima.

The only curves he ever takes notice of, are on page 3.

And when he switched to the socialist worker, he lost track of even those.

So you studied to build bridges and design electronic boards all in one
course. My, oh my. Was this skule in Toytown.




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I think you misunderstood. Best put Rockwool up to joist height then
lay Kingspan over the joists, this prevents thermal bridging via the
joists.

Wouldn't the boards get quite squashed where they lay on the joists?
Obviously, crosslaying is the best solution. However, if the OP is only
going to fit stuff between the joists, it may as well be Kingspan than
rockwool.

Christian.

"Christian McArdle" wrote in message
et...
I think you misunderstood. Best put Rockwool up to joist height then
lay Kingspan over the joists, this prevents thermal bridging via the
joists.

Wouldn't the boards get quite squashed where they lay on the joists?

Many ways in which to get around that. I think Kingspan do a board which
mean for floating floors so this can be used, or you can always counter
baton with baton the thickness of the Kingspan and put boards over that.

Obviously, crosslaying is the best solution. However, if the OP is only
going to fit stuff between the joists, it may as well be Kingspan than
rockwool.

That is true, but There will be lost of waste with Kingspan, unless you path
it all in and the remainder scatter around the loft in places that nothing
is stored or walked on.


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"Christian McArdle" wrote in message
et...

However, if the OP is only
going to fit stuff between the joists,
it may as well be Kingspan than
rockwool.

Laying over the joists and taping up the joins will add it air-tightness
too.


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"Dean Richard Benson" wrote in
message newsan.2004.01.21.18.28.06.252332@spamlessharker hill.co.uk...
On Wed, 21 Jan 2004 16:29:12 +0000, Christian McArdle wrote:

Yes. The law of diminishing returns says that 350mm is the best
environmentally speaking. Any more and the environmental cost of
manufacturing and transporting the insulant is higher than the energy
saved.
100mm is definitely on the low side. 200mm would be better. The
difference
between 200mm and 350mm isn't that great.

Some useful info in there. Leads me to even more questions....

- with currently having a 100mm joist height, should i either increase the
joist height (cross joists) or just cross-lay the insulation over the top
of the 100mm.

- If you insulation up to 350mm, how are you meant to ever reach places in
your loft without falling through the ceiling ;P


The problem is that with a 100mm joist height you aren't meant to store
anything, other than insulation in your lost. Its one of those cases where
the builders use the absolute minimum they can get away in order to save a
few quid and you end up with some valuable storage space that you
effectively can't use!

cheers

David

The problem is that with a 100mm joist height you aren't meant to
store anything, other than insulation in your lost.

Nah. I've seen loads of houses with 100mm loft joists. They're all used for
storage!

Floor joist sizes are so large to avoid flexing the ceiling as people move
about, not to stop the things collapsing. Light or even medium storage is
usually OK, as there is little movement. Any bad results are usually a few
hairline cracks, not stuff piling into the room below. Obvious, large water
tanks or big boxes of books need special consideration.

Christian.

On Thu, 22 Jan 2004 09:36:06 -0000, "IMM" wrote:


"Andy Hall" wrote in message
.. .


They talk about all sorts of things. This one is pure pandering to
be seen to be doing something towards the Kyoto protocol. It has no
basis in economics or anything else when put into the context of where
domestic energy should be being saved.

This is ********!

You're absolutely right. It is total ******** and political game
playing.

The Whole House Book has a graph that says 350-400mm is
the current optimum price/performance.

Based on what? Show the calculations. I wasn't talking about the
total environmental cost or anything of that nature, just very simple
economics of

a) what is the heat loss with insulation thickness X?
b) what is it with thickness Y?
c) what's the energy saving and what does that cost at today's prices?
d) what does it cost to install insulation to achieve that?

That is what the Whole House Book did.

Then please explain how it arrived at figures that justify these
figures, because it is not based on the parameters that I have
detailed.


If fuel rises, which it will as
cheap energy is coming to an end, then this is meaningless and 450-500mm
is
the optimum.

That's a separate issue. Can you suggest a rate at which fuel
prices would need to rise to justify that?

Hold a fdiger to the air. Fuel porices will rise. They always do. Also
enviro taxes will start to bite.

This is arm waving. Yes we know all of that, but the figures are
not solid. Do you have energy price projections for 5 and 10 years
time? You can make some guesses and take a punt, but that is all it
is.

In this instance, the cost of totally filling the roof with insulation
if you want is not significant so it doesn't matter.

My point was that focussing on this alone is misleading.



Even if energy loss through the roof were reduced to zero by going to
the ridiculous lengths that you are suggesting,

I'm nor suggesting it. People who have done the research are.

Based on what? If it includes all of the ecological factors involved
in manufacturing insulation as well then that is another discussion.
It can be a valid one for people for whom that is an important
concern, but it is separate nonetheless to the simple economic
argument.

if the walls and
window losses are not reduced then the difference made is worthless.

Keep in mind that the topic here was concerning the value *today* and
in the near future of increasing loft insulation.

Near future? What will that be? Ermmm...

Exactly. Who knows.


In terms of return on investment, it may be interesting to do because
it is inexpensive, but then the returns are relatively little as well.

Loft insulation is cheap and very easy to do compared to other parts of the
house. So it is worth packing in as much as possible.

I didn't dispute that it was cheap or easy to do, but does result in
loss of space or extra timbers etc. to make it usable.

It doesn't make sense to make an energy saving of 100W in the loft
when several kW are going out through the walls.



My point was that focussing on this, while ignoring other much more
significant losses is the wrong focus. There is not much point in
saving £10 a year on what goes through the roof if £200 is going
through other surfaces. Even if energy goes up in price by a
factor of ten, that principle still applies. All that changes is the
urgency and the economics not the priority.

Ecohouse - A Design Guide says there is no upper limit to
insulation, as it will pay for itself eventually.

It's very easy to sit down and write airy-fairy books when it's other
people's money being spent. Almost anything pays for itself
*eventually* - that's a very weak argument.

In the book EcoHouse - A Design Guide, they gave a study that calculated in
1987 200mm was the optimum in walls at the then current fuel prices.

Based on what?



As fuel prices rise and the insulation manufacturing costs too, the whole
payback calcs were skewed somewhat. So they calculated insulation levels on
energy to make insulation. They came to the thickness of 650mm. The
conclusion was that what constrains you is the detailing of the structure to
hold as much insulation as possible. So, install as much as possible.

Again based on what?


There is also the comfort
factor of high insulation and that it also keeps the house cool from a
loft
hat may be 55C in summer.

Having any insulation will do that. It doesn't need to be knee deep
to achieve it.

The bigger the temp difference on each side and the bigger the heat
transfer. More insulation prevents heat transfer.

Yes. There is a simple equation covering this, and it is easy to
demonstrate that the major difference is between no insulation and
some rather than some and twice or three times as much.


..andy

To email, substitute .nospam with .gl

David Moodie wrote:

"Dean Richard Benson" wrote in
message newsan.2004.01.21.18.28.06.252332@spamlessharker hill.co.uk...

On Wed, 21 Jan 2004 16:29:12 +0000, Christian McArdle wrote:


Yes. The law of diminishing returns says that 350mm is the best
environmentally speaking. Any more and the environmental cost of
manufacturing and transporting the insulant is higher than the energy

saved.

100mm is definitely on the low side. 200mm would be better. The

difference

between 200mm and 350mm isn't that great.

Some useful info in there. Leads me to even more questions....

- with currently having a 100mm joist height, should i either increase the
joist height (cross joists) or just cross-lay the insulation over the top
of the 100mm.

- If you insulation up to 350mm, how are you meant to ever reach places in
your loft without falling through the ceiling ;P



The problem is that with a 100mm joist height you aren't meant to store
anything, other than insulation in your lost. Its one of those cases where
the builders use the absolute minimum they can get away in order to save a
few quid and you end up with some valuable storage space that you
effectively can't use!



Yes, and that is where cross laying more joists , maybe herringbone
bracing and a few hangers up to teh ridge/radfters makes sense. Total
insulation depth comes up to maybe 8 inches with only where the joists
cross as 'cold bridges' and boardiong out the loft stops draughts getong
in any less than perefectly insulated places.

I have just complete boarding out my loft with 150mm insulation
(rockwool) and its made a lot of difference. Its icy up there when the
wind blows (silly building regs vents are enough to take every ounce of
moist air out in about 1.2 seconds). Once you get to this sort of
insulation depth, the real danger is tiny cracks that allow air movement
alongside celotex and through the rockwool.

If yu have as I have, hollow rockwool filled walls, you then discover
that things like e.g. power sockets, or the odd crack round a window
frame, lets in a tiny icy draught...from air moving THROUGH the
insulation and getting into the rooms.

Going to IMMlike levels of insulation only works if you can stop up each
and every one of these micro draughts: This takes patience, and
decorators caulk and frame sealer inside, and attention to detail up in
the loft as well.

I sometimes wonde if much more limited ventialtion, and an electrical
dehumidifier in the loft might not be a more energy efficient way to
keep a cold roof dry, and allow the loft airspace itself to become an
insulator...



cheers

David

Christian McArdle wrote:

The problem is that with a 100mm joist height you aren't meant to
store anything, other than insulation in your lost.


Nah. I've seen loads of houses with 100mm loft joists. They're all used for
storage!

Floor joist sizes are so large to avoid flexing the ceiling as people move
about, not to stop the things collapsing. Light or even medium storage is
usually OK, as there is little movement. Any bad results are usually a few
hairline cracks, not stuff piling into the room below. Obvious, large water
tanks or big boxes of books need special consideration.



This is very true. Timber will suffer unacceptable deformation long
before it breaks. Especually on longish spans (a couple of meters or more)


Christian.

IMM wrote:

"The Natural Philosopher" wrote in message
...

Andy Hall wrote:



Even if energy loss through the roof were reduced to zero by going to
the ridiculous lengths that you are suggesting, if the walls and
window losses are not reduced then the difference made is worthless.


IMM's uni only taught him about straight lines and binary thinking.

Its no good talking to him about curves and maxima/minima.

The only curves he ever takes notice of, are on page 3.

And when he switched to the socialist worker, he lost track of even those.


So you studied to build bridges and design electronic boards all in one
course. My, oh my. Was this skule in Toytown.



Yes.
It was in Cambridge.





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"Andy Hall" wrote in message
...

If fuel rises, which it will as
cheap energy is coming to an end,
then this is meaningless and 450-500mm
is the optimum.

That's a separate issue. Can you suggest
a rate at which fuel prices would need to
rise to justify that?

Hold a finger to the air. Fuel prices will rise.
They always do. Also
enviro taxes will start to bite.

This is arm waving.

But arm waving with realism. All I read is that energy will become more
scarce and more expensive. As it becomes more exp[expensive so will
insulation too. best pack it in now while it is cheap enough. You will not
regret it in the future.

Yes we know all of that, but the figures are
not solid. Do you have energy price
projections for 5 and 10 years
time? You can make some guesses and
take a punt, but that is all it is.

See above.

In this instance, the cost of totally filling the roof with insulation
if you want is not significant so it doesn't matter.

My point was that focussing on this alone is misleading.

Who said focus on this alone?I never. I said pack in as much as you can
while it is cheap as it will not be, neither will energy, in the future.
probably sooner than later too.

Even if energy loss through the roof were reduced to zero by going to
the ridiculous lengths that you are suggesting,

I'm nor suggesting it. People who have done the research are.

Based on what?

See above.

In terms of return on investment, it may be interesting to do because
it is inexpensive, but then the returns are relatively little as well.

Loft insulation is cheap and very easy to do compared to other parts of
the
house. So it is worth packing in as much as possible.

I didn't dispute that it was cheap or
easy to do, but does result in
loss of space or extra timbers etc.
to make it usable.

That is still cheap and easy to do, even for a DIYer.

It doesn't make sense to make an
energy saving of 100W in the loft
when several kW are going out through the walls.

It does, as you can tackle the loft easily and cheaply. You plug as many
holes as you can, even the small ones.

My point was that focussing on this, while ignoring other much more
significant losses is the wrong focus. There is not much point in
saving £10 a year on what goes through the roof if £200 is going
through other surfaces. Even if energy goes up in price by a
factor of ten, that principle still applies. All that changes is the
urgency and the economics not the priority.

Ecohouse - A Design Guide says there is no upper limit to
insulation, as it will pay for itself eventually.

It's very easy to sit down and write airy-fairy books when it's other
people's money being spent. Almost anything pays for itself
*eventually* - that's a very weak argument.

In the book EcoHouse - A Design Guide, they gave a study that calculated
in
1987 200mm was the optimum in walls at the then current fuel prices.

Based on what?

"at the then current fuel prices"

As fuel prices rise and the insulation manufacturing costs too, the whole
payback calcs were skewed somewhat. So they calculated insulation levels
on
energy to make insulation. They came to the thickness of 650mm. The
conclusion was that what constrains you is the detailing of the structure
to
hold as much insulation as possible. So, install as much as possible.

Again based on what?

That is clear above.




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"The Natural Philosopher" wrote in message
...

Going to IMMlike levels of insulation

Not mine. Experts on the topic conclude this.

only works if you can stop up each
and every one of these micro draughts:

I have always said caulk every hole into the loft: around pipes, cables,
etc. Also fit a vapour barrier on the loft floor, stapling down, then put
insulation over.

I sometimes wonde if much more limited ventialtion, and an electrical
dehumidifier in the loft might not be a more energy efficient way to
keep a cold roof dry, and allow the loft airspace itself to become an
insulator...

I have always though that may be beneficial. Seal up all vents and install
one. The BCO would not like at, as if the de-humidifier fails you have
problems. An accurate humidistat would need to be fitted to reduce running
costs. There again install a vapour barrier on the loft floor to prevent
vapour getting in.




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"The Natural Philosopher" wrote in message
...
IMM wrote:

"The Natural Philosopher" wrote in message
...

Andy Hall wrote:



Even if energy loss through the roof were reduced to zero by going to
the ridiculous lengths that you are suggesting, if the walls and
window losses are not reduced then the difference made is worthless.


IMM's uni only taught him about straight lines and binary thinking.

Its no good talking to him about curves and maxima/minima.

The only curves he ever takes notice of, are on page 3.

And when he switched to the socialist worker, he lost track of even
those.


So you studied to build bridges and design electronic boards all in one
course. My, oh my. Was this skule in Toytown.

Yes.
It was in Cambridge.

A bulldozer should be run through the lot of it.


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On Thu, 22 Jan 2004 12:54:46 -0000, "IMM" wrote:


"Andy Hall" wrote in message
.. .

If fuel rises, which it will as
cheap energy is coming to an end,
then this is meaningless and 450-500mm
is the optimum.

That's a separate issue. Can you suggest
a rate at which fuel prices would need to
rise to justify that?

Hold a finger to the air. Fuel prices will rise.
They always do. Also
enviro taxes will start to bite.

This is arm waving.

But arm waving with realism. All I read is that energy will become more
scarce and more expensive. As it becomes more exp[expensive so will
insulation too. best pack it in now while it is cheap enough. You will not
regret it in the future.

This is all qualitative stuff.



Yes we know all of that, but the figures are
not solid. Do you have energy price
projections for 5 and 10 years
time? You can make some guesses and
take a punt, but that is all it is.

See above.

In this instance, the cost of totally filling the roof with insulation
if you want is not significant so it doesn't matter.

My point was that focussing on this alone is misleading.

Who said focus on this alone?I never. I said pack in as much as you can
while it is cheap as it will not be, neither will energy, in the future.
probably sooner than later too.

At some point it may well be interesting to do this, but at a saving
of a tenner a year, when several hundred quids worth of heat is going
out through the walls means that the focus should be on that now and
situations where there is no roof insulation at all.



Even if energy loss through the roof were reduced to zero by going to
the ridiculous lengths that you are suggesting,

I'm nor suggesting it. People who have done the research are.

Based on what?

See above.

Quantitative arguments not qualitative.



In terms of return on investment, it may be interesting to do because
it is inexpensive, but then the returns are relatively little as well.

Loft insulation is cheap and very easy to do compared to other parts of
the
house. So it is worth packing in as much as possible.

I didn't dispute that it was cheap or
easy to do, but does result in
loss of space or extra timbers etc.
to make it usable.

That is still cheap and easy to do, even for a DIYer.

It doesn't make sense to make an
energy saving of 100W in the loft
when several kW are going out through the walls.

It does, as you can tackle the loft easily and cheaply. You plug as many
holes as you can, even the small ones.

That is not a reason. It's the difference between turning a light
on or not - in cost terms a very small light.


My point was that focussing on this, while ignoring other much more
significant losses is the wrong focus. There is not much point in
saving £10 a year on what goes through the roof if £200 is going
through other surfaces. Even if energy goes up in price by a
factor of ten, that principle still applies. All that changes is the
urgency and the economics not the priority.

Ecohouse - A Design Guide says there is no upper limit to
insulation, as it will pay for itself eventually.

It's very easy to sit down and write airy-fairy books when it's other
people's money being spent. Almost anything pays for itself
*eventually* - that's a very weak argument.

In the book EcoHouse - A Design Guide, they gave a study that calculated
in
1987 200mm was the optimum in walls at the then current fuel prices.

Based on what?

"at the then current fuel prices"

On the immediate energy cost or with everything taken into account
including replacement sandals for the author?



As fuel prices rise and the insulation manufacturing costs too, the whole
payback calcs were skewed somewhat. So they calculated insulation levels
on
energy to make insulation. They came to the thickness of 650mm. The
conclusion was that what constrains you is the detailing of the structure
to
hold as much insulation as possible. So, install as much as possible.

Again based on what?

That is clear above.

You haven't made a convincing case at all.





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..andy

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On Thu, 22 Jan 2004 13:03:15 -0000, "IMM" wrote:


"The Natural Philosopher" wrote in message
...
IMM wrote:

"The Natural Philosopher" wrote in message
...

Andy Hall wrote:



Even if energy loss through the roof were reduced to zero by going to
the ridiculous lengths that you are suggesting, if the walls and
window losses are not reduced then the difference made is worthless.


IMM's uni only taught him about straight lines and binary thinking.

Its no good talking to him about curves and maxima/minima.

The only curves he ever takes notice of, are on page 3.

And when he switched to the socialist worker, he lost track of even
those.


So you studied to build bridges and design electronic boards all in one
course. My, oh my. Was this skule in Toytown.

Yes.
It was in Cambridge.

A bulldozer should be run through the lot of it.

Philistine......


---

..andy

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