Passive solar design (PSD)

Passive solar design (PSD) basically optimises a building's form, fabric and orientation to maximise solar gain from autumn to spring, whilst minimising it during the warmest part of the summer. At the same time, daylight is maximised at all times, adding to the overall wellbeing and comfort of the occupants.

PSD costs very little to implement and can make a significant contribution to the energy efficiency of a building throughout its life, whilst incurring little or no maintenance costs.

In the UK climate, PSD is mostly used to reduce domestic heating requirements, although it is not increasingly being used in non-domestic buildings, where the emphasis is often on maximising daylight without increasing the risk of overheating. PSD requires a whole-building approach to design, in which the envelope (particularly the glazing) is designed in unison with the structure's thermal mass to ensure optimal admission and absorption of solar gains during the heating season. PSD can be applied with varying levels of sophistication, including the use of both sunspaces and Trombe walls.