Here's part of the solar water heating system of one of the schools. Hot water from the roof collectors is stored in a insulated tank (on the left). While solar water heating systems are one of the most cost effective solar investments a homeowner can make, it may not make sense to design it for 100% of hot water needs. A tankless water heater augments the solar system when needed. Since it heats water only when it's needed instead of all the time like a regular water heater, the system can be very efficient. Also, these take up a very small amount of space. This unit is made by Seisco.

Some of the schools used ceiling fans to reduce both cooling and heating costs. Most modern ceiling fans can be run in reverse to push warm air down from the ceiling in the winter.

You can see the Washington Monument through the window.

The Department of Energy showed a small windmill. These are available for sale. They produce power in the range of a few hundred watts. Generally, though, you need sustained winds that are greater than the DC area typically gets. They could work out for some vacation homes, though.

The University of Massachusetts Dartmouth house will be given to a family affected by Hurricane Katrina. The unit on the back was not part of the competition, but will make a bigger house for the family than the Decathlon's 800 square foot limit allowed. The school works with Habitat for Humanity. Habitat is making efforts to use more energy efficiency and renewable energy in their homes in some parts of the country.