Passive solar energy is nothing new. About 14% of space heating in an ordinary British home comes from solar energy through walls and windows. Passive solar design tries to optimise the amount of energy that can be derived directly from the sun. Over 25% of UK primary energy goes towards heating buildings, more than for any other purpose. By incorporating passive solar design into new buildings, annual fuel bills can be cut by about a third, with corresponding carbon dioxide savings. This helps to reduce global warming.

In addition, the increased daylight means that the need for additional electric lighting is lowered.  Passive solar design can be best applied in new buildings, where the orientation of the building, the size and position of the glazed areas, the density of buildings within an area, and materials used for the remainder of the structure are designed to maximise free solar gains. Designing a property to maximise free solar gain need not add to the price of construction. 

Studies on houses in Milton Keynes have shown that low cost passive solar design features and draughtproofing and insulating measures reduced heating bills by 40%. Savings paid back the costs in two years. Inclusion of a a conservatory can save up to 20% of annual heating bills although this is strongly dependent on the size of the house, siting, design and materials used. A well designed conservatory acts as extra insulation for the house, preheats the ventilation air and provides direct solar heating to the intervening wall, which is convected into the house, as well as providing additional living space. 

Design elements to optimize direct solar gain are: 

1. Use thermal storage within the masonry walls to allow sun to be 'soaked up' during daylight

hours and released into the building at night 

2. Incorporate a responsive, zoned heating system to automatically cut in when and where

necessary. 

3. Main glazed areas should face within 30 degrees either side of south. 

4. Principal living areas; bedrooms, sitting rooms, those requiring more heat, should have large,

south facing glazing. Infrequently used rooms should be positioned on the north, east and west

sides, with smaller glazed areas. 

5. Overshadowing from trees and other buildings should be minimised. 

6. The building should be well insulated to minimise heat losses and avoid overheating in summer. 

7. Pay close attention to the type of window/glazing used.

For passive solar gains, more heat must flow in than out.

One example of integrated solar design housing is at Skotteparken in Denmark