On 04/01/2017 18:56, Rod Speed wrote:
RJH wrote
Rod Speed wrote
RJH wrote

I've read a few articles now from the peer reviewed scientific press
on the environmental impact of insulation materials.

While useful and doubtless scholarly (on my lay reading) in the
sense of seeing which materials work, in what quantity and why,
reported wider environmental benefits are misleading.

Nope.

Not a single one even mentions the 'CO2 cost' of production, only
effects post-fit -

That's because the CO2 cost of the production of the
insulation is a trivial part of the dramatic reduction
in the CO2 produced when heating the place.

Well, a very rough calculation taking my house and insulating just
floors and roof with Celotex would suggest that it would take about 5
years to offset the CO2 used in the manufacture of the insulation
material (Celotex 160kgCO2e/m3,

Where are you getting that number from ?


A guess based on the figures given on the 'superhomes' site. Celotex
don't seem to cite a figure. On reflection I may be way out (I think I
used expanding foam on what I thought might be a conservative estimate)
- do you have a figure?

If I had decent figures i'd do a proper calculation.

snip

We'll just have to agree to differ on how trivial production and
installation factors might be . . .

Money saved is a different matter - depends a great deal on
installation costs. Far and away the best value thing I've done here -
two alcoves, about a day, less than £100. But it'd still take some
yeasr to repay the materials costs.

Sure, but with a new house, hardly ever doesnt the cost of
insulation pay for itself quite quickly when done properly.


Yes, it certainly can. My experience (of managing housing) is that using
the building properly can be a big factor, but that said, well worth doing.

IIRC, building regs have been relaxed to require a lower level of
insulation, and/or carbon neutral design/build, as an attempt to
stimulate the property market. And increase builders' profits.


--
Cheers, Rob