Sunspaces or solariums are essentially used for passive heating purposes in cold climates. An integration of the direct gain and thermal storage concepts is achieved in this approach. Solar radiation admitted directly into the sunspace heats up the air, which by convection and conduction through the mass wall reaches the living space. It consists essentially of a sunspace or a green house constructed on the south side (in the northern hemisphere) of the building with a thick mass wall linking the two. The basic requirements of this type of building are:

  1. A glazed south facing collector space attached, yet distinct from the building.
  2. Thermal storage link between the collector and living space for heat transfer.

The location of the sunspace depends on the building design and orientation of the sun. The area of contact between the sunspace and the living space determines its size. Thermal mass must be located where winter sun can reach it. Floors, walls, benches, rock bed or covered pools of water can be used to store heat.

Temperature inside the sunspace must be controlled depending on its usage. Shading to prevent overheating in summer and movable insulation and shutters to prevent heat loss in winter can be provided. If the sunspaces are used for plantation or green house purpose, humidity control must be incorporated to prevent mould from growing on the storage mass or other materials kept inside.