What if your house changed color with the seasons? This ‘climate-responsive’ paint could make it happen

American designer Joe Doucet has developed a pigment that changes color, depending on the temperature. It could be a game changer for people living in the world’s temperate zones.

When Joe Doucet bought a new house in Katonah, New York, he wanted to make it as environmentally friendly as possible. As a designer and inventor, he immediately found himself wondering whether the exterior of his home could play a role in mitigating the effects of climate change. “One of the things I had not really considered before was: What color should I paint the house?” he told CNN, speaking in a video call. It’s well known that light-colored buildings reflect heat and stay cooler while darker ones absorb — just compare chilly Scandinavia’s black housing tradition to the whitewashed homes found across warm Mediterranean countries. But what shade would perform best in a climate like New York’s, with hot summers but dark and snowy winters? Doucet started by 3D-printing small scale models of his house, complete with similar levels of insulation, and painting them in different colors. Over the course of a year, he found that in winter the inside temperature of the black model was on average 7 degrees Fahrenheit warmer than the white one. In summer, the white model house was 12 degrees Fahrenheit cooler. “The answer wasn’t, ‘Should I paint it black or white?’ The answer was: It should be black in winter and white in summer,” he said of the findings. “It is not really feasible to paint a house twice a year. I began to think, ‘Surely there are other ways of doing this?’” Doucet’s solution was inspired by his childhood interest in mood rings, which feature manmade “stones” that change appearance according to the wearer’s finger temperature.