In the summer, black roofs absorb heat from the sun and cause air-conditioned buildings to heat up. That wastes energy and money. One solution is to paint roofs white, but then they lose the heating benefits of a black roof during the winter, when you want to warm your building.

Themeleon has developed a roof coating that changes color with the weather. The roof is white on hot days to keep your building cool and black on cold days to keep it warm. The simplicity of the design and the use of commodity materials leads to an inexpensive, robust system. We are currently working to refine this technology.