The sun can meet the entire annual space heating needs of buildings in sunnier parts of the world. However, in much cloudier and cold climates, the sun can still make a very useful contribution.

Passive solar design involves the application of design principles, such as south-facing windows, to make sure that excess heat loss is avoided and solar radiation is captured, in order to minimise the need for heating and lighting.

Buildings should be designed with large windows in the south facing walls to maximize radiation absorption and small windows in the north facing walls to reduce heat loss. The windows admit solar radiation directly into the living spaces where it can be stored by thermal mass in the form of floors, walls or ceilings

Passive Solar Design is most easily incorporated into new build projects, or as part of a major refurbishment. This is because design considerations must be made as to how to channel the warmth around the building and how to control thermal gains when a desired temperature is reached.

Existing buildings can also benefit by the addition of a conservatory to the south side, saving 800kWh per year of space heating energy mainly due to the preheating of ventilation air.

A passive solar system provides heating/cooling without mechanical collectors to convert solar energy into heat nor pumps or fans to distribute the heat. The energy is used directly, relying on natural energy flows to drive it.

PSD will minimize the energy consumption of a property for the lifetime of the building, and help to minimize running costs. This will have major benefits for tenants/owners, as well as major carbon savings.

Passive solar design has a number of environmental advantages as every opportunity to capitalise on natural radiation and daylight will minimise reliance on fossil-fuel generated electricity, which in turn reduces carbon-dioxide emissions. There is also has the added advantage of significant savings in energy costs.