Passive Solar Design is a simple and commonsense approach to energy efficiency.
When done correctly it can be a highly cost-effective way of conserving energy and keeping buildings warm in winter and cool in summer.
It requires a holistic approach to design. The 10 simple steps outlined in this presentation ALL need to be considered and applied correctly for a passive solar design to work properly. If even one of the steps is done incorrectly serious problems can arise and the resulting building can be hard to heat in the winter and/or hard to keep cool in the summer.
It relies on the fact that the sun is in a different part of the sky in summer than in winter. So passive solar design also requires an understanding of how the sun moves through the sky at different times of the day and year. (Please note that the information below applies to the Southern Hemisphere only).
This difference between the summer sunpath and the winter sunpath is the foundation on which Passive Solar Design is built. With the correct orientation, window placement, and eave overhangs the sun will enter the building in the winter to warm it and stay out in the summer to help keep it cool.