m Ransley wrote:
Wake up senile nick, R value is R value, a standardised measurement used
to measure insulations effectiveness, resistance to heat flow. Polyiso
foilfaced, Both Sides is R 7.2" new, 6.8R" stabilised. Your mythical
dreamworld of R 6 added with 2 sheets of foil does not exist anywhere in
reality or at any store on this planet, or it would be sold as R 12.8*
polyiso, and it is not.


Senile is not the word.

Nick appears to believe that he is a reincarnation of a mythical
all-knowing, all-powerful being. His attitude towards others reinforces
this idea with almost everything he posts.

patent holders are idiots.

Facts are false.

Everyone else besides Nick are absolute morons is the message he conveys

Aluminum foil is tested for 'emissivity' not R value. That is the test
is to see how good a RADIATOR it is not how good and INSULATOR it is.
If it is used for cookware and electric power distribution, it CAN'T be
an insulator of heat or electricity.

Aluminum is therefore a RADIANT barrier, and may also act as a vapor
retarder, but it does NOT improve an INSULATION material's ability to
restrict the movement of heat, EXCEPT by REFLECTING the heat - but it
RADIATES to BOTH sides of the foil.
An AIRSPACE MUST be incorporated in order for the foil to be effective
and the literature that Nick quotes indicates this as well.

So Foil helps, BUT only when there is a air gap. Foil faced insulation
is more effective than non foil faced insulation only when there is an
air gap for the foil to radiate heat into. Even then, if there is no
circulation of that air, we get a heat buildup between the foil and the
outside sheathing that could take most of the night to dissipate.