How does a radiant barrier refelect heat, when the reflection is towards the interior, not away from the house

Question

Is it suppose to refect heat from the sun, away, or does it work by reflecting the cool from inside, back into the house, keeping less of the cool from escaping? I don't see how it would reflect anything away from the house, being that the reflecting image in towards the interior.

Answer 1

Radiant barriers work on two levels: reflectivity and emissivity

reflectivity will reflect (97%) the radiant heat back where it came from. Because of this, a two sided radiant barrier is highly recommended to get savings in both summer and winter months.

Then you have emissivity, which is the ability of the material not to re-radiate that 3% absorbed heat to the cold side of the radiant barrier. If you are going to use the single sided stuff (they suck) then point the reflective side towards the sun if your in a hot climate and towards the inside if you are in a cold climate.

Better yet, just pay a few extra bucks and get a good double sided radiant barrier and get savings all year round.

This is a good radiant barrier: http://www.raflect.com