This Texas building has self-cooling walls

September 6, 2023

When Houston hit 109 degrees in late August—tying an all-time temperature record for the city—26 of the previous 27 days also had been over 100 degrees. As the hot city gets even hotter because of climate change, it also keeps using more energy for air conditioning, reports Fast Company.

But in the suburb of Conroe, one new building is pioneering a strategy to stay cooler: “self-cooling” concrete walls with a scalloped shape that helps repel heat. The deep grooves in the corrugated pattern give more surface area for heat to move away from the wall.

“In a way, the wall is working a bit like a very large radiator,” says Phu Hoang, founding director of the architecture studio, Modu, which worked on the design with a climate-focused engineering firm called Transsolar. In tests, Hoang and cofounder Rachely Rotem discovered that the patterned material could stay as much as 18 degrees cooler than a flat wall.

The newly-completed building, a 14,000-square-foot commercial space that will soon house retail stores and medical offices, also has white walls to reflect sunlight,—another design choice that keeps the interior cooler. Since white paint can sometimes look dirtier, the architects chose a type of paint that repels dirt. “You get the environmental performance without the associated maintenance,” says Hoang.

Two dozen architectural fins also help shade windows. In front of each store, there’s a pocket garden with plants that can provide more shade; some plants, like jasmine, will grow onto the fins.

“We are trying to find solutions for the social dependency on air conditioning,” says Rotem. Since air conditioners pump heat outside, as AC use grows, it’s literally making cities hotter. And the massive amount of electricity used by air conditioners is contributing to climate change, leading to more extreme heat. Air conditioners are responsible for nearly 2 billion tons of CO2 emissions annually, or more than the airline industry. By the middle of the century, global air conditioner use is expected to roughly triple.

The shift to renewable energy will help reduce the carbon footprint of AC, but it’s still key to cut energy use from cooling both because it’s expensive for consumers and because it’s straining the grid at a time when there’s also growing demand from electric cars, induction stoves, and other parts of the broader energy transition.

Passive design can help, and can be adapted for any location. In Modu’s other projects, “we always have passive energy design strategies that we incorporate with the overall idea of reducing energy use,” says Hoang.

In the new development in Texas, tenants haven’t moved in and the HVAC system isn’t running, which means there’s isn’t data yet on energy savings. But owner Anh Gip says the difference is already noticeable. “In Texas right now, we’re in triple digit heat,” she says. “I haven’t run the air conditioning at all. But when I walk inside the building, it feels cooler.”

Research contact: @FastCompany