"Gary" wrote in message
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I am very sceptical of these barriers. What they need to do is have two
identical houses in the same place, one with the barrier and one with
rockwool. Then do data monitoring for a year or more. The British ASA
ruled against Actis, a French maker, as the tests were not good enough.
There is no testing model to explain. After all this time you would have
thought they could have done tests on an Actis Triso9 house and an
identical house without Actis with 200mm of insulation in the walls. If
there was a clear difference I'm sure they would be crowing from the
rooftops with all data printed and freely given out at every bus stop.

This stuff is not cheap. As far as I can see it is expensive bubble
wrap - until proper meaningful realistic independent tests have been
undertaken.


Hi,

The FSEC has done radiant barrier work -- here is one report:
http://www.fsec.ucf.edu/bldg/pubs/rbs/

I am aware of that and have previously read it. It is quite old now, 1999.
At the time the performance in cold climates from other non-comprehensive
tests in the USA was not too encouraging.

If you go to their site and search on Radiant Barrier, a lot of stuff
comes up.

I think that www.SouthFace.org has also done work on radiant barrier.

These are good and independant outfits -- I would tend to belive what they
publish. It seems like the bottom line turns out to be about 10% saving
on cooling.

Gary

Actis claim the equivalent of 210mm of Rockwool. I believe they do have an
effect on cooling when pinned to the rafters of a roof. What is the overall
claim for rockwool equivalent thickness for heating by tests in the US?
There must be some ballpark. No one is going to type in Nicks program, they
read the makers blurb, or test results to confirm the blurb.

I have the impression much of any heat saving is because this stuff is
air-tight. More the draught prevention is making the difference rather than
the reflective qualities of the material itself. I hope I am wrong and it
does what they say. If so my attic gets done out in it. Until something
more concrete in realistic more real world testing the jury is still out and
it stays out of my attic. 35C here means I may have to act with the attic by
next summer - but using what has to be determined.