Solar Decathlon shines light on net zero-energy homes (photos)

To compete, student teams need to design and build a net zero-energy house. Then they need to transport it and reassemble it in Washington D.C. where it will be judged and viewed by the public.

Many houses incorporate similar design techniques. The New Zealand house on the bottom right, for example, has the roof sloped to take advantage of sunlight for internal lighting. The roof pitch also allows the house to collect water for storage. In an effort to use local materials, the building uses sheep's wool as insulation.