Nineteen solar-powered homes designed by students in the U.S. and as far off as New Zealand will be on display at West Potomac Park.
Some took two years of research to construct, One has an exterior made of vinyl stuffed with recycled blue jeans. Inside, stowable furniture and "x-box connect" technology that controls the lights:
Each home must generate more energy than it uses and is judged on efficiency, affordability and aesthetics.
The University of Maryland made the cut this year with a home that mirrors the Chesapeake Bay ecosystem.
"It slowly releases the water back into the environment - and also cleans it," said David Daily of the University of Maryland engineering project. "So all the water you use is clean."
Consumers can see new energy-saving ideas for their own homes and the students learn from each other.