Basic Principles of Passive Solar Design

Basic Principles of Passive Solar Design


The principles of passive solar design for a comfortable energy efficie

nt house can be summarised very simply:

  INSULATE: Use insulation to slow the flow of heat in and out of the house – heat from the sun is used more effectively in houses that are well-insulated. Insulation helps to maintain more constant internal temperatures and reduces the need for heating in winter and cooling in summer.


  GLAZE: Use glazing to bring heat from the sun into the house – though glass must be selected, placed and sized carefully as it is a poor insulator (windows should be double glazed as a minimum to reduce heat loss).

  ADD THERMAL MASS: Use heavyweight materials (thermal mass) to soak up heat from the sun and release it slowly into the house when temperatures drop. A house with appropriate mass will maintain more comfortable temperatures – it will overheat less often and not get as cold overnight.

  STOP AIR LEAKAGE: Use weather-stripping, high-quality sealants and less complicated house designs to reduce air leakage. Once a house is well-insulated and appropriately glazed, the biggest potential heat loss is through draughts around windows, doors and other construction joints.

  SHADE: Use external shading to manage the heat gain from the sun. Well-designed window systems must not only collect heat from the sun when desirable, but also exclude it at times when it might cause overheating.

  VENTILATE: Use openable windows and other ventilation to reduce overheating and maintain good indoor air quality. Appropriate placement of windows for good cross flow of air through rooms will make them more effective for cooling on hot days. Good ventilation also helps to reduce condensation and remove cooking and other odours.


 Other important factors that you should consider when designing a house, such as site selection, house placement and orientation, are covered in Chapter Three. It is important to consider these, in combination with the factors above, when designing a comfortable energy efficient house.