This Reflective Coating May Aid in Keeping Buildings Cooler

A team of Columbia University researchers thinks that painting buildings with a new type of coating could help reduce the amount of air conditioning we use, which in turn would help reduce the impact on climate change, reports Fast Company writer Adele Peters.

The researchers created a polymer coating that also has nano-to-micro-scale pockets of air that turn it white. “It’s like snow,” says Yuan Yang, an assistant professor of materials science and engineering at Columbia. Snow, he explains, is filled with micron-sized crystals of ice that create tiny pockets of air that scatter light–the effect that makes snow white rather than transparent like ice, and highly reflective. “Our paint can be much more reflective than normal paint,” he says.

Regular white paint might reflect 85% of the sunlight that hits it. The new coating, depending on its thickness, could reflect as much as 99%. (If used with colored paint, it’s less effective, but also keeps buildings cooler than they would otherwise be; the coating is also less effective in areas with high humidity.) In a hot, dry city like Phoenix, the white coating could keep a building around 10 degrees Fahrenheit cooler than the outdoor air on a summer day.