Provided by John Brennan: Senior Lecturer, Edinburgh School of Architecture and Landscape Architecture.
What, Why, How, Extras
Design for orientation is a fundamental step to ensure that buildings work with the passage of the sun across the sky. Knowledge of sunpaths for any site is fundamental in design building facades to let in light and passive solar gain, as well as reducing glare and overheating to the building interior. It is important to remember that the position of the sun in the sky is dynamic, changing according to time of day, time of year and the site’s latitude.
This diagram sets out the key definitions used when describing the sun’s passage across a site. © John Brennan
Well-orientated buildings maximise daylighting through building facades reducing the need for artificial lighting. Some typologies especially housing can be zoned to ensure different functional uses receive sunlight at different times of the day. Buildings that maximise sunlight are ideal for the incorporation of passive solar collection techniques that can reduce carbon use and enhance user comfort. A careful strategy can also mitigate overheating and glare when sunlight is excessive. You should know how the sun interacts with your building in high summer and the depths of winter.
Google SketchUp model showing building design orientated to maximise south light. © John Brennan
Housing in temperate regions can benefit from admitting the sun into the building interior. Openings should be primarily orientated southwards, consider the use of conservatories and buffer spaces. Kitchens are better facing east, living rooms to the south and west. Bedrooms are often better to the north to avoid light disturbance.
Simple criteria for the organisation of spaces in housing to maximise positive effects of orientation. © John Brennan
- Office buildings typically are about the reduction of excessive solar gain and glare. This is because of a greater preponderance of glazed facades and also higher internal gains from people, computers etc. Use glazing due south sparingly and incorporate shading devices.
Knowledge of building orientation can prioritise where to provide protection for glazed facades. Scottish National Heritage building Inverness. Architects: Keppie. © John Brennan
- Don’t be precious about orientating buildings exactly due south to maximise solar gain. ±20 degrees is fine, ±30 degrees is still useful.
- Remember to model solar paths dynamically to pick up on all eventualities. Ensure you model context as overshadowing can fundamentally change a building’s response.
- Step 1: There is no single design procedure to design for orientation. However, you need to model your proposal in a package such as Google SketchUp.
- Step 2: Ensure the building is properly placed on its site in relation to north and the location either geographically or in terms of latitude or longitude is entered.
- Step 3: Use a sun or shadow tool to model the building at seasonal extremities.
- Step 4: Be conservative in the use of glazing to heavily exposed sides.
- Step 5: Model the use of solar shading devices.
- Step 6: You can quantify solar gain coming through glazing over a year using in a domestic context, really simple SAP tools. Other packages such as Autodesk Ecotect and IES VE-ware can model solar gain and possible overheating of a building model.
- Step 7: Remember orientation is about protection and mitigation of sunlight in buildings as well as accommodating solar gain.
Brown and Dekay 2000. 'Sun Wind and Light' John Wiley. (An excellent primer looking at buildings' relationship with the sun.)
Boubekri 2008. 'Daylighting, architecture and health: building design strategies'. Architectural Press. (This publication highlights the importance of natural lighting and therefore building orientation for the health and well being of the building user)
- Szokolay 2008 'Introduction to Architectural Science: The Basis of Sustainable Design' Architectural Press (a good general introduction).
Google sketchup - for quick and easy shadow projection.
Autodesk Ecotect - an excellent and interactive way of looking at the effect of sunpath on buildings.