I've been pretty happy with my purchase of rFoil from
http://www.blueridgecompany.com/hydr...rge+Assortment
They have a large selection of Foil/Bubble/Foil and Foil/Double
Bubble/Foil, as well as Concrete Barrier foil if you are doing Radiant
In Floor heating under a concrete slab, which is what I did.