Scientists Have Created the Whitest Paint Ever—and It Might Help Cool the Planet

The world's whitest paint can reflect up to 98 percent of the sun's radiation, lowering indoor temperatures and the need for air conditioning.
Xiulin Ruan and a sample of his cooling paint.
Xiulin Ruan and a sample of his cooling paint. / Courtesy of Purdue University/Jared Pike

A few years after the world went wild for vantablack, a material which can absorb virtually all light, a new hue has emerged on the other end of the spectrum: a white paint so reflective that it could one day provide a solution to the climate crisis.

According to The New York Times, a Purdue University team led by mechanical engineering professor Xiulin Ruan has developed an ultra-white coating that is able to reflect up to 98 percent of the sun’s rays. If used on rooftops, it could dramatically decrease indoor temperatures normally warmed up by heat absorption. On its surface, the paint can be up to 8°F cooler than ambient air during the day and up to 19°F cooler at night.

“If you were to use this paint to cover a roof area of about 1000 square feet, we estimate that you could get a cooling power of 10 kilowatts,” Ruan said in a statement. “That’s more powerful than the central air conditioners used by most houses.”

Black asphalt, for example, could be scorching under midday sun, while the paint could be cool to the touch. The mixture, which contains barium sulfate, also scatters light, meaning it wouldn’t be uncomfortable to look at.

Heat-reflective paints are not new, but the Purdue recipe is a considerable bump in performance that has the potential to reduce cooling costs. It would, of course, need to be utilized on roofs that are able to accept paint. Roofing shingles wouldn’t necessarily qualify, though some shingles already come in heat-reflective versions. It’s also possible that the accumulation of dirt might affect performance over time—at least, until it’s cleaned.

Purdue recently developed a lighter-weight version of the paint, which could have applications in automotive coatings, footwear, and clothing. It may be commercially available next year.