White houses are often boring, but they can just save the planet. As USA Today reports, researchers from Purdue University have developed an ultra-white paint (it just earned a Guinness World Record) that reflects 98.1 percent of solar radiation while emitting infrared heat. Because this leaves the surface cooler than the environment (ordinary paint heats the surface), it can in some cases effectively replace air conditioning – it produces a cooling power of 10kW for a 1,000sq. ft. roof, if more than a typical AC unit for home.
Existing paints are made to reflect heat, but they do not reflect more than 90 percent of sunlight and do not cool surfaces. The team also did not have much breathing – an even whiter paint would have compromised it perhaps.
The trick was to use a high ratio of barium sulfate, a compound you often see in cosmetics and photo paper, in various particle sizes. The wider range of sizes helps to spread more of the light spectrum and thus reflects more sunlight.
It is not clear how close this extremely white paint is to your local store, but the researchers are fully excited to commercialize their work. They have partnered with a company to mass produce and sell the paint, and have already filed patents. However, if it complies with billing, it can play an important role in combating climate change. It can reduce or eliminate the need for air conditioning in some homes, especially in hot regions with sufficient sunlight. This can reduce emissions and energy consumption, and can save you some money on hot summer days.