Radiant barrier

[Eric in North TX]

I keep running into to people planning on installing this coating the inside of their attic roof. I tend to roll my eyes, but maybe somebody could enlighten me. 1st; how could it work when the light/heat is already having to pass through roughly an inch of tar and wood. 2nd: even if it did work, what possible difference could it make. Reducing the heat load in an attic ( assuming this works, which is quite an assumption) doesn't seem like the best bang for the buck for reducing your hvac costs.

[ransley]

Maybe

has info or links.

[trader4]

It works by stopping the radiant heat from continuing on into the attic and warming it up more. Ever sit under one of those radiant heaters that are used on patios during cool weather? The radiant heat warms you. Imagine putting a thin radiant blocking barrier between the heat source and you. You would no longer be warmed by it.

If its stapled to the rafters, which is where it's usually deployed, there is air flow from soffits up to a ridge vent, taking the heat between the barrier and the roof out.

Depends on the climate, existing insulation, is the SC unit in the attic, etc. I've seen data that show in hot climates it does make a significant difference. As for the bang for the buck, it's very cheap to install. You can do an attic yourself for $250 or so.

That would be a good place to start.

[Rick Samuel]