White Roofs

SECRETARY OF ENERGY STEVEN CHU: These are buildings with white roofs. If you use a white roof and you have – happen to have air conditioning, depending on the geometry of the building, you can save 10 – as much as 15 percent, decrease in energy, by just simply having a white roof. If you don’t have air conditioning, that means your building, your home, is cooler in the summer and, because the emissivity is lower, it’s actually warmer in the winter, slightly. Now, there is something else about white roofs and white – light-colored pavements. It actually changes the reflectivity, the so-called albedo of the Earth. So the sunlight comes in; it’s reflected back into space. There is no greenhouse cap on this. And so Art Rosenfeld and his colleagues have done a calculation: If you replace all the building roofs today with white roofs, and you go to cement-style pavement instead of blacktop-style pavement, it would be a reflection of the sunlight back into space that would be the equivalent as if you took off all the automobiles of the world for 11 years.

OK? And guess what? It’s about the same cost, white versus black. In fact, if you – if the cars go to light-colored colors, or what we call smart colors, that reflect in the infrared, you can actually reduce the size of the air conditioner in a car. Until you do that, they’re going to have to have a single-size air conditioner. And then, once you reduce the size of the compressor, you save a lot of money and you save a lot of energy. So this is something very simple that we can do immediately..