New 'Whitest' White Paint Reflects 98% Of Sunlight, Can Cool Homes More Than A/C

"If you were to use this paint to cover a roof area of about 1,000 square feet, we estimate that you could get a cooling power of 10 kilowatts. That’s more powerful than the central air conditioners used by most houses," Xiulin Ruan, an engineer at Purdue, explained in a press release.

Most objects painted white will still absorb some light. As the temperature outside climbs, generally, white objects also get hotter. But this paint is different. Objects pained with this new white remain cooler than what surrounds them.

First, the paint has a high concentration of barium sulfate. This is the same stuff used in photo paper and cosmetics to make it white. And, in high concentrations, barium sulfate is super reflective.

Second, the engineers included different-sized particles of barium sulfate. The amount of light reflected is determined by the size of the barium sulfate particles. Including multiple sizes means that a larger spectrum of light can be reflected.

Experiments have shown that the paint can keep objects up to 19°F (4.5°C) cooler outdoors during the daytime. These savings can help boost climate change initiatives. It is already a common practice to paint the roofs of buildings white to reduce heat in the building. This new paint could take this practice to the next level.

Ruan explained to The Guardian, "Our paint can help fight against global warming by helping to cool the Earth – that’s the cool point."

"We think this paint will be made widely available to the market, in one or two years, I hope, if we do it quickly."

h/t: Purdue University