solar heating

solar heating, the use of sunlight to heat water or air in buildings. There are two types of solar heating, passive and active. Passive heating relies on architectural design to heat buildings. The building’s site, structure, and materials can all be utilized to maximize the heating (and lighting) effect of the sunlight falling on it, thereby lowering or even eliminating its fuel requirement. A well-insulated building with a large glass window facing south, for instance,...