A "passive" solar house keeps the home warm in the winter by storing and distributing the sun's heat and cool in the summer by blocking the sun's ray. A comfortable indoor temperature is maintained without the use of mechanical equipment. For passive heating and cooling, the plan of the house, careful site selection and planning, construction materials, building features and other aspects of the home must be carefully considered before design even begins. Passive solar houses can be built in any architectural style and in any part of the country.
More: http://www.nrel.gov/buildings/passive_solar.html
