Looking at the future of the energy-efficient home at the 2009 Solar Decathlon

Mother Nature didn't make it easy for the teams that took part in 2009 Solar Decathlon, hosted by the U.S. Department of Energy on the National Mall in Washington, D.C. The homes designed and built by 20 college and university teams were put through the weather wringer during the final days of the event last weekend, with cold, rainy, overcast weather prevailing—not exactly ideal conditions for solar-powered homes.

The homes in the 2009 Solar Decathlon were judged on 10 characteristics, including architecture, comfort, lighting, appliances, hot water, home entertainment, and market viability, or how easy and affordable the home is to build. Readily available products used in the houses include compact fluorescent lightbulbs and LED lighting, induction cooktops, front-loading washing machines, energy-efficient windows, bamboo flooring, and low-VOC paint.

Team Germany took first prize in the fourth installment of this competition (see its home in the video above) earning 908.29 points out of a possible 1,000, followed by the University of Illinois at Urbana-Champaign, and Team California with 863.08 points. See the complete final standings.

With umbrella in hand and galoshes on feet, I checked out the future of the energy-efficient home. (You can avoid any inclement weather by visiting the 20 projects via a virtual tour.)

While the competition calls for uniformity in overall size—houses can be no larger than 800 square feet—the first thing I noticed was how different the houses looked from one another. With teams from throughout the U.S. as well as Canada, German, Puerto Rico, and Spain, each featured a design unique to its climate and region.

Indoor/outdoor living was a big part of Team California's Refract House, a collaboration between Santa Clara University and California College of the Arts. Rooms faced an outdoor-living space, blurring the lines between indoors and outdoors, and intelligent controls of windows and blinds helped maximize passive heating and cooling. Reclaimed-redwood paneling and a unique fabric skirting used to hide the underside of the solar panels on the roofs made the solar technology less visually intrusive. This entry merited a first place for its architecture.

Team Ontario/British Columbia, the fourth-place collaboration among the University of Waterloo, Ryerson University, and Simon Fraser University, took a different approach since it was designing for northern latitudes. The team's North House featured photovoltaic panels on the roof and its south, east, and west sides to make use of low-angle sunlight in colder months. A phase-change material under the maple floors is designed to absorb heat during the day that comes in through its floor-to-ceiling windows and radiates the heat at night. A dynamic shading system automatically opens and closes shades based on time of day and the longitude and latitude of the home.

The Iowa State University team's Interlock House meets all regulations for accessibility under the  Americans With Disabilities Act. This 12th-place-overall house also used a number of home-grown technologies, including soy-bio farm insulation, vacuum-insulated door panels made by a national window manufacturer based in Iowa, and ceramic tiles and furniture made by students.—Celia Kuperszmid Lehrman | e-mail | Twitter | Forums | Facebook

Essential information: While you might not be able to go off the grid completely as some of the Solar Decathlon houses can on sunny days, you can cut your annual energy bill by up to $1,500, perhaps by using a solar water heater or pellet stove. If you're in the market for new appliances, take advantage of the $300 million State Energy Efficient Appliance Rebate Program. Learn more in our cash for clunkers for appliances FAQ.