Let’s get some facts straight: there is no such thing as radiant barrier paint.
The term “radiant barrier” is supposed to describe products that reflect over 90% of radiant energy, and these paint products simply cannot do that. The term radiant barrier has been misconstrued by the people who install the paint and it’s essentially like trying to call a hamburger a prime steak; it’s misleading and simply not truthful.
For the record, both the radiant barrier spray paint and the radiant barrier foil will reflect (i.e. not emit) radiant heat. However, the fine print exists when the best available radiant barrier paint can only reflect about 75% of the radiant heat transfer. Meanwhile, the radiant barrier foil will reflect 97% of the radiant heat transfer.
Radiant barrier foil is actually the best radiant barrier you can use; you can either install it yourself or hire a professional installer who uses our foil insulation.
Radiant barrier spray-on paint is essentially liquid foil. While not all radiant barrier paints are the same, basically they are made by grinding pure aluminum into a fine powder and then mixing it into clear paint. Once the clear paint dries the aluminum powder forms a layer of aluminum.
The best radiant barrier spray spray is only available to commercial contractors, and is an environmentally safe, water-based low-e paint called HeatBloc-75, Radiance e.25 or Lo/MIT. When the paint is installed correctly, it will reflect about 75% of the radiant heat and can be a very good product.