On Sat, 29 Dec 2007 13:51:04 +0000, a particular chimpanzee, Mike
Barnard randomly hit the keyboard
and produced:

I need a basic chart showing the heat losses through a loft area if
there is no insulation, 50mm, 100mm up to the 265mm nominal 'perfect'
insulation. Anyone know where there is one or the facts (validated)
so I can draw one up for myself?

I am googling, and it's ongoing, but all I find so far is detailed
tech guides or company ads. I'll bet someone on here has a link
already!

The 2002 Approved Document L1 (Dwellings) is still available on the
Planning Portal
(http://www.planningportal.gov.uk/upl...ADL1_2002.pdf).
This had some useful and not-so-useful tables in the back.

What you will hopefully see is that it's not a simple straight-line
graph where doubling the insulation halves the heat loss. It isn't.
It also depends on the proportion of heat loss through bridging
elements such as ceiling joists. It is also subject to diminishing
returns, where a small initial amount of insulation has seemingly
dramatic effects but subsequent thicknesses have less and less effect.
This is where other factors affecting heat loss and energy use such as
airtightness come in.
--
Hugo Nebula
"If no-one on the internet wants a piece of this,
just how far from the pack have you strayed?"