Early consideration of orientation can have a significant impact on how much sun enters the building and therefore its energy performance and thermal comfort for occupants. Allowing solar gain can reduce how much energy is needed to heat the building in winter, conversely it can also cause summer overheating if not kept in balance.

Dual aspect buildings facing predominantly north and south allow for controllable solar gain to the south. This means buildings can benefit from useful solar gain in the winter while easily excluding excess solar gain in the summer.

The low sun angle directed on east and particularly west facing facades can be more difficult to manage in summer, leaving buildings prone to excess solar gain and overheating if not designed carefully.

Where a building has a high performing building fabric it becomes more important to balance and regulate solar gains through the building design, to make use of the heat in winter without overheating in summer.

There may be constraints within the site and the larger context, such as complementing the existing urban pattern or challenging infill sites where a north south orientation is not feasible. Ensuring that as many facades as possible face south is best practice. An east-west orientation is less optimal for performance, and when this is required, other characteristics such as the 'form factor and window ratios must be optimised.

Design Actions

• Orientate the largest building elevations within +/- 30° of south
• Site layout should maximise number of dwellings with a main living room that has at least one window on a wall facing 90° due south.
• +/- 30° south – this term is reference several times. To capture useful solar gains the largest elevations should be facing as close to south as possible. 30° either side of south is used as an approximate range so designers can make an informed judgement.

Case Study:

Goldsmith Street
Mikhail Riches Architects

At goldsmith street, the homes were arranged facing due South. The buildings were 2-3 stories high and streets positioned 14m apart, reducing overshadowing. Shading was provided above south facing windows to reduce excess solar gain in summer.