A building form with ample surface area exposed to direct sunlight in winter can easily incorporate passive heating systems.
Most heating needs occur in buildings at mid to high latitudes (30º – 60º). At these latitudes, the winter sun is low in the sky, striking the side of the building that faces the equator, i.e., the solar side (south in the Northern Hemisphere, and north in the Southern Hemisphere).
To maximize the solar exposure of a building:
- Elongate a building along the east-west axis to maximize the surface area exposed to direct winter sunlight.
- Locate occupied spaces along the solar side of the building.
- Alternatively, stagger, step, stack, and/or align indoor spaces and building forms to ensure they have adequate wall surface areas facing the equator.
Other building shapes and spaces needing sunlight that do not have solar facing wall surfaces can be heated by solar-oriented skylights, clerestories, and integrated sunspaces.