On Sat, 11 Jun 2005 22:20:50 +0100, "Mike" wrote:


"Andy Hall" wrote in message
.. .
On Fri, 10 Jun 2005 13:46:09 +0100, "Doctor Evil"
wrote:


"Pet @ www.gymratz.co.uk" wrote in message
.uk...
Mike wrote:
Assuming you mean fibre or Rockwool, that doesn't even meet the
current
building regs, let alone actually make a real attempt to save energy.
265mm
is needed so regard 300 as a min.

Surely the gains of going from 200 to 300 mm of rockwoolor whatever
would be pretty insignificant compared to heat loss through walls and
windows in a 70's construction house?

In a bungalow, the biggest heat loss is via the ceilings as that is the
largest area. it is worth making the ceiling air-tight, sealing around
pipes
and ceiling roses, and filling up to 400mm of rockwool. It will keep the
house warm and cool.


Good grief. It was 300mm last week. Have you bought shares in
Pilkington or Rockwool or something?

As anybody with a knowledge of basic physics knows, the difference
between 200 and 400mm of insulation in a roof is negligible in
comparison with heat transmission through the walls, even in a
bungalow.

That rather depends on the insulation in the walls. If it's 100mm of foam
the roof definitely dominates, especially in a bungalow. But if the cavity
is empty - get it filled !



100mm of foam in the walls of a 70s house is not very likely. If
there is no insulation in the walls as is quite likely, then the walls
certainly dominate in comparison with the difference between 200mm and
400mm of insulation in the roof.

Depending on the dimensions, the walls may well still dominate even if
they have some insulation.



--

..andy

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