August 7, 2007 12:12 PM PDT
A key design element of this green building is its metal roof, which on first thought may not seem energy-efficient. After all, metal absorbs heat, and air conditioners consume a lot of electricity.
But PowerHouse's metal roof serves two specific purposes: heating the house in the cold season and generating electricity. Builders run plastic water tubes under the roof. The water is heated by the sun and distributed through the house to supply hot water and warm the house. The house also has solar electric panels to generate electricity during the day.
Photo by Martin LaMonica/CNET News.com
