Scientists at MIT and the University of Hong Kong have recently collaborated to develop new heat-rejecting window coatings that could help reduce air conditioning costs. To accomplish this feat, the heat-rejecting window coatings turn slightly opaque when exposed to temperatures above 32 degrees Celsius. By turning opaque, the coating reflects 70 percent of the sun's heat and in-turn reduces interior temperatures and reduces the load on an air conditioner.
The heat-blocking technology of the window coating comes from its construction of tiny water-filled spheres made into a standard poly material. While this technology has been explored before, researchers at MIT and University of Hong Kong realized that the spheres would also need to match the wavelength of infrared light responsible to most solar heating. The heat-rejecting window coatings have the same feel as plastic wrap and could easily be put on any existing windows.