The Winning Homes in the Solar Decathlon Are …

U.S. Dept. of Energy Secretary Jennifer Granholm announced the winners of the 2021 Solar Decathlon Build Challenge. These are prototype homes that university teams built to demonstrate some of the newest approaches for reducing energy use in homes and buildings, while still making them affordable to build.

Evaluated for 10 different metrics, including energy efficiency, architectural design, innovation, and market potential, the homes had to be as technically impressive as they were feasible to build. This year’s top finishers also happened to explore efficiency strategies for places with extreme climates—the kinds of conditions climate change will make more common for a larger number of houses.

The highest-ranked home in the competition was designed and built by a team from the University of Colorado in Boulder. Their two-story, two-unit house was designed to offer an efficient and affordable alternative to the high-priced houses in the region. Accommodating the cold and snowy climate, the home managed to reduce its estimated annual utilities cost to about 10% of a conventionally built home in the area.

Using equipment such as solar-tracking photovoltaic panels, an energy-recovery ventilator that reuses exhaust heat from the home’s appliances, and highly efficient air conditioning through zone-based ductless mini-split heat pumps, the home generates an estimated 321 kilowatt-hours of excess electricity that is stored in on-site batteries. A rentable accessory dwelling unit provides a source of extra income for the owners while adding another affordable housing option for the region’s lower-income families.

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