This house is heated by the sun during winter. (Source: © ArchiVIZ / stock.adobe.com)

Devices that harness energy from the sun without requiring electricity or equipment for energy conversion or storage; a typical example of a passive solar system is a greenhouse. Most easily, a passive solar system is incorporated into the architecture so that the interior is heated by the low sun in winter but shaded in summer. A Trombe wall is another example of a passive solar system. The sun oriented dark wall in the interior is heated by the sun, and then warms the house with its heat.