Passive solar design principles have been incorporated into building design for thousands of years on every continent. It makes sense to take advantage of the sun’s warmth to heat a home in the winter, and to minimize the sun’s heat in the summer while taking advantage of natural evening


  • Site Orientation:  Site the structure so that the longest sides are aligned within 20 degrees of the east/west axis.
  • Window Sizing and Placement:  Install the most window area along the south side to let in the sunlight and warmth, less window area on the north side to let in subdued light and views while minimizing cold drafts in the winter, and the least window area on the east and west sides to protect from glare and heat of the rising and setting sun.
  • Overhang Sizing and Placement:  Size overhangs to allow full direct sunlight into the home during the winter and little to no direct sunlight in the summer.
  • Interior Thermal Mass Sizing and Placement:  Size and place interior thermal mass to store the sun’s energy within the structure to prevent overheating during winter days and release the sun’s energy for night-time heating. Interior thermal mass will also cool down with summer night-time ventilation and absorb heat out of the structure’s interior air during summer days.
  • Room Layout:  As a general rule of thumb, locate the most active rooms (family, kitchen, study, etc) on the south side of a structure, with morning active rooms (kitchen, breakfast nook, etc) on the east side and afternoon active rooms on the west side (family, living room, dining room, etc), and the least active or quiet rooms on the north side (bedrooms, closets, utility rooms, bathrooms, etc).
  • Ventilation:  Ensure adequate natural ventilation for health and cooling by installing openable windows on the windward and leeward sides of the structure, and/or openable windows on different levels of the structure to create a chimney effect. If necessary, augment natural ventilation with ceiling or whole house fans.
  • Insulation:  Install minimum R-38 ceiling/roof insulation, minimum R-21 wall insulation to keep winter heat inside and summer heat outside.