Photograph by Thomas Kelsey, U.S. Dept. of Energy
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Reporters view the compact, stackable home designed and built by students at New York City College of Technology on October 7, 2015, at the U.S. Department of Energy's biennial Solar Decathlon in Irvine, California.

Photograph by Thomas Kelsey, U.S. Dept. of Energy

These 14 Sleek Solar Homes Do More Than Produce Power

Fewer college teams built homes to compete in this year’s Solar Decathlon, but their gee-whiz features might offer a surprising glimpse of the future.

They’re not simply places to live. They charge cars, grow food, collect water, and generate electricity during blackouts. These Dwell-like beauties might just make those with bigger homes a bit envious.

The University at Buffalo home, for example, has an indoor greenhouse for growing food year-round. Orange County’s team features a vertical garden, surf shower and—for the boomerang generation—detached studio. To withstand storms like the tornado that flattened the nearby town of Joplin, Missouri’s Crowder College and Drury University use reinforced walls surrounded by an impact-resistant fence.

The homes offer smart windows, accordion doors, and movable walls. Plus, they can charge a car. “We’re going to hook it up and charge it with the power of the sun,” Steve Speights, an engineering student at California State University in Sacramento, says in a video about his team’s home, complete with carport.

Welcome to the Solar Decathlon 2015, a biennial U.S.-sponsored contest that began Thursday in Irvine, California. Collegiate teams from around the world compete to build the most attractive, affordable, and energy-efficient home. Via solar panels, the homes produce at least as much energy as they use. Via rainwater capture, they reuse water.

These small homes—1,000 square feet or less—go well beyond solar technology to showcase not only smart design but also innovative ways to address drought or extreme weather. Some are engineering marvels.

“It’s like the biggest jigsaw puzzle you’ve even seen,” Solar Decathlon director Richard King says of Clemson University’s home, made of thousands of pieces of flat-packed plywood that lock together like LEGO.

Despite its wow factor, this competition has a cloudy future. It's losing competitors at a time when the U.S. solar industry is booming and other countries—China, Colombia, and United Arab Emirates—are planning similar decathlons. Six of the initial 20 teams withdrew, including Stanford, Yale, and Vanderbilt. The result: This year’s event is the smallest since the Department of Energy launched the U.S. decathlon in 2002.

Clemson University's home

What Happened?

“It was a confluence of things,” King says, noting two teams dropped out almost immediately, because their faculty advisers had moved to other schools. Another reason: cash. The projects often cost at least $250,000, and DOE gave each team $50,00 in seed money, down from $100,000 in prior years.

Several teams said they couldn’t raise enough money. They get in-kind donations from companies, but they still have to design and build homes, ship them in pieces, and reassemble them within days at the competition.

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Triple-filtered, recycled greywater waters at hydroponic garden at the home of Missouri University of Science and Technology on October 6, 2105, at the Solar Decathlon in Irvine, California. 

Yale pulled out less than two months ago, citing inadequate funds. Architecture student Pablo Ponce de Leon, who worked on the project, said Yale’s endowment—one of the largest in the world for universities—is locked in investments or earmarked for other purposes such as building residential colleges.


“If you raise the money, fine, but we’re not going to fundraise for you,” he says was the message from the development office. He says his student-led team didn’t get started early enough or have a dedicated faculty adviser. “It’s a little disappointing,” he says of the withdrawal, adding the decathlon encourages cutting-edge solutions.

“It’s very expensive and time-consuming,” says Sandy Stannard, architecture professor at California Polytechnic State University, citing the demands of creating a smart home. Her team’s house doubles its living space with a 15-foot glass wall in the living room that folds back like an accordion, and it reduces energy demand with a bio-based material that absorbs and releases heat. She says Cal Poly participated in the 2005 contest, adding with a laugh: “It took 10 years to recover.”

“It’s become increasingly competitive,” says Alex McDonald, a graduate student in mechanical engineering at the University of California, Irvine. He says the Orange County team’s house, which mimics California’s state flower—the golden poppy—by opening to the sun during the day and closing at night—is quite ambitious.


The house has windows that automatically open and close, depending on the weather, as well as a personal 3D printer and small thermoplastic recycling system that allow residents to break down unneeded objects and reuse the material for new products.

“We pushed hard to develop disruptive technologies,” McDonald says, noting his team was still working out some glitches. He says the home is so complex that it needs a project manager with “borderline OCD.”

Homes Gain Complexity

King agrees that each subsequent decathlon “raises the bar.” In 2011, to encourage affordability, the competition began penalizing homes that cost more than $250,000. This year, it required them to charge a car to run 25 miles a day.

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A circular window inside the home built by students at the Missouri University of Science and Technology provides a unique view of the entry by the California Polytechnic State University, San Luis Obispo, on October 5, 2015, at the U.S. Department of Energy's biennial Solar Decathlon in Irvine, California.

“We expanded the Solar Decathlon from the house to the household,” King says. Why? He says he cut his electric bill to zero when he built his own solar-powered home six years ago, but because of his family’s cars, its total carbon emissions were only halved. So he wanted the competition to address that other half—the cars.

The teams address local conditions. To deal with urban density, New York City College of Technology built a stackable house. To address the drought, the University of Texas at Austin—partnering with Germany’s Technische Universitaet Muenchen—captures rainwater and reuses the greywater that’s left from showers or dishwashers. It has an under-deck system to purify and store the water for drinking or irrigation.


Several built storm-proof homes. Recalling the damage of Hurricane Sandy in 2012, students at New Jersey-based Stevens Institute of Technology use fiber-composite shutters and an “islanding” solar array that will power the house during blackouts and even allow neighbors to charge their electronic devices.

The teams, some of which include community colleges or foreign universities, are judged on 10 criteria that include affordability, architecture, engineering, and market appeal. The overall winner is named October 17, after which the competition ends.

King says he expects good public turnout despite having fewer homes. As for 2017, he plans a different approach to avoid teams dropping out. Rather than giving them upfront cash, he’ll offer each a prize ranging from $50,000 to $300,000. Right now, winners only get bragging rights. Next time, he says: “You’ll have to show up to get your money.”

The story is part of a special series that explores energy issues. For more, visit The Great Energy Challenge .

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