Mark Golden in Phys.Org:
Stanford University scientists have invented a new kind of paint that can keep homes and other buildings cooler in the summer and warmer in the winter, significantly reducing energy use, costs, and greenhouse gas emissions.
…Current low-emissivity paints usually have a metallic silver or gray color, the aesthetics of which limit their use. The newly invented paints have two layers applied separately: an infrared reflective bottom layer using aluminum flakes and an ultrathin, infrared transparent upper layer using inorganic nanoparticles that comes in a wide range of colors. The infrared spectrum of sunlight causes 49% of natural heating of the planet when it is absorbed by surfaces. For keeping heat out, the paint can be applied to exterior walls and roofs. Most of this infrared light passes through the color layer of the new paints, reflects off the lower layer, and passes back out as light, not being absorbed by the building materials as heat. To keep heat inside, the paints are applied to interior walls, where again, the lower layer reflects the infrared waves that transfer energy across space and are invisible to the human eye.