A Trombe wall is used to reduce the use of a building's heating and cooling systems through passive solar design. It consists of a dark colored wall of high thermal mass facing the sun, with glazing spaced in front to leave a small air space. The glazing traps solar radiation like a small greenhouse.
A glazed wall is built on the winter sunny side of a building, which then radiates heat to the interior. The air in the space between the glass and the wall heats up, and is often vented to the inside.
Rooms heated by a Trombe wall feel more comfortable than those heated by forced-air systems, even at lower air temperatures, because of the radiantly warm surface of the wall.
During hot weather, a Trombe wall with vents can be used as a thermosiphon. If vents are placed at the top of the glazing, then air from the room will be pulled out by convection in the air gap between glazing and mass wall. This form of passive ventilation is called a solar chimney.