Solar Orientation

For maximum solar gain, a building will be located, oriented and designed to maximise window area facing north (or within 20 degrees of north) – for example, a shallow east-west floor plan. However, this will depend on the site’s shape, orientation and topography. For example, an east-west floor plan will not be possible on a narrow north-south site.

Orientation for solar gain will also depend on other factors such as proximity to neighbouring buildings and trees that shade the site. For solar gain, as well as considering location, orientation and window size and placement, it is also important to consider the thermal performance and solar heat gain efficiency of  the glazing unit itself.

While solar gain for passive heating is important, other considerations include noise, daylighting, protection from prevailing winds, access to breezes for ventilation, shade to prevent summer overheating and glare, views, privacy, access, indoor/outdoor flow, owners’ preferences, and covenants and planning restrictions.

Where passive cooling is more of a priority than passive heating, the building should be oriented to take advantage of prevailing breezes.

Orientation, location and layout should be considered from the beginning of the design process – ideally, from the time the site is being selected. Once a building has been completed, it is impractical and expensive to reorient later.

Good orientation, together with thermal mass and the right glazing and insulation, can cut the heating requirements in a house by half or more, reducing energy costs and greenhouse gas emissions.

Effective solar orientation requires a good understanding of sun paths at the site at different times of the year.