Used by the government on Stealth bombers. Could also be used by homeowners on the exterior of their houses. Tex-Cote's CoolWall coating systems, when covering the exterior of a building, can actually cool the surface by tens of degrees.
The coating is an enamel that has reflective pigments in it, cooling the surface of a building and hence letting you use less cooling energy during hot months. We're impressed by this kind of performance and the price is reasonable at $30-35 per gallon.
(via Dwell, March 2007).