Larger international companies with more research and development resources have joined smaller firms that traditionally have dominated the solar field. With those leaps forward, it shouldn't be surprising that solar-home building is on the upswing. Materials involved in passive solar design are in the glass or glass-products family, and can be used to make up entire walls and sections of the roof. South-facing portions of the house, where sunlight falls longest and strongest, are built of reinforced, specially designed glass or feature skylights. But not every season is cold.
Solar heating is reversible.
Designing a house properly, with the right building materials and landscaping that provides shade, will let cool air in at night and keep it there during the day. This is not a new idea. Matthew Schultz of Lansdowne, a preservationist and consultant, said floor plans of older houses had rooms that lined up to provide cross-ventilation. Windows had louvered shutters indoors and out. The shutters would be closed during the heat of the day, but after sunset, the louvers were opened to let in the breeze, he said.