I live in eastern Canada (Nova Scotia) and have been searching the FHB forum for information on foil used to keep heat in. It seems that the advice ranges from it’s just scam to it “might work” The companies that produce the stuff (bubble poly foil stuff) seem to have lots of data in favor(not surprising. If foil touches the back of drywall it becomes a conductor of heat, does this override it’s radiant properties? You think it would be a rather simple series of tests with small wall section mockups and heat source. Have any independent parties done these tests for a cold climate? Home building seems to be full of these kind of issues, house wrap vs felt, fiberglass vs cellulose. Interesting but without definitive info I sometimes second guess my decisions.
Thanks
Alan
Replies
It does some good, but the circumstances where it works are limited. Not a substitute for real insulation.
If you want to test it you're welcome to set up the test yourself. Like you indicate, it would be fairly simple to do, and if you do it yourself you can best duplicate your own "real life" conditions. Just be sure properly control convection currents within the structure.
In the USA the Federal Trade Commission has issued a couple of restraining orders to some of these companies about their use of "effective" R-Value. To which the companies reply, "Gosh, golly, shucks, maybe our testing methodologies might be a little misleading. Sorry."
There has been a bunch of insulation research by the folks at Oak Ridge National Labs. Check out their web site.
Steve.
radiant barriers require an airspace to work. They only reflect radiant energy, and radiant energy is heat transfer through space. When it touches, it is conduction, not radiant.
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Most bubble wraps have no CCMC approval number on them, which means they have not been scientifically tested to Canadian Building Materials Standards.
A caution also, do not use face side ( foil side) up, underneath concrete floor slabs,as the aluminum foil dissolves when in contact with wet concrete.
That piece of info is never found in the advertizing , eh?
Sure, if you read the data sheets and install instructions, this kind of product is meant to be used with an inch or inch and a half of air space in front ofit to function as a radiant barrier. There are circumstances where it helps in conjunction with other insulations as part of a system
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As a builder from Nova Scotia I can tell you there are some issues regarding foil faced insullation. You should talk to your local building inspector and/or the Nova scotia Home Builders' Association. The two issues being r-values and vapour barriers.