Broadly speaking, solar heating is any type of heating produced by the Sun's energy. Even the radiant warmth of sunlight on bare skin can be thought of as solar heating. In the energy industry, solar heating usually refers to any type of heating supplied to an enclosed space through the use of solar energy.

Solar heating is divided into two classifications: active and passive. Almost every building receives at least some passive solar heating through the direct action of sunlight on the outside surface of the building or the irradiation of curtains, floors and other surfaces through windows exposed to the Sun. Active solar heating is produced when a system is installed to store or redistribute collected solar energy.

The typical active solar heating system uses absorber panels, usually mounted on a roof or sloping wall, which consist of glass- or plastic-covered black surfaces over which water flows. The water absorbs solar heat from the black surface. From there it is either circulated throughout the structure using a pump or recirculating system, or carried to a generator where it is converted to electricity and stored in batteries for later use. The least expensive type of active solar heating traps heat in underground rock during the day where it can be stored and used during the night.

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