"Aaron Fude" wrote in message
...

Just received a quote for roof insulation with closed cell foam between
the rafters. The quote is for 3" and I am being told that 3" is 90% as
good as 6". Do I believe them?

American taxpayers fund a government housing standards
laboratory precisely to answer questions like this (probably
free to householders.)

--
Don Phillipson
Carlsbad Springs
(Ottawa, Canada)