White houses are often boring, but they might just save the planet. As USA Today reports, Purdue University researchers have developed an ultra-white paint (it just earned a Guinness World Record) that reflects 98.1 percent of solar radiation while outputting infrared heat. As this leaves the surface cooler than the environment (regular paint warms the surface), it could effectively replace air conditioning in some cases — it produces a cooling power of 10kW for a 1,000sq. ft. roof, or more than a typical house AC unit.
There are existing paints made to reflect heat, but they reflect no more than 90 percent of sunlight and don't cool surfaces. The team didn't have much breathing room, either — an even whiter paint might have compromised it.
The trick was to use a high ratio of barium sulfate, a compound you often see in cosmetics and photo paper, in varying particle sizes. The wider range of sizes helps scatter more of the light spectrum and thus reflect more sunlight.
It's not clear how close this extremely white paint is to your local store, but the researchers are fully bent on commercializing their work. They've teamed with a company to mass-produce and sell the paint, and have already filed patents. If it lives up to the billing, though, it could play an important role in fighting climate change. It could reduce or eliminate the need for air conditioning in some homes, particularly in warm regions with ample sunlight. That could reduce emissions and power consumption, and might save you some money on hot summer days.