Shade on the facade: not ornament, a climate tool

Over the past twenty years our cities have filled with fully glazed buildings. Glass promises transparency and lightness; but in a sunny climate an unshaded glass facade turns the building into a greenhouse. The result is air-conditioning running at full capacity for much of the year and blinds kept closed all day. A facade designed to be transparent ends up shut by its occupants.

Shade is most effective when resolved outside the facade. Once sunlight passes through glass it becomes heat inside, and blinds can only partly stop it. External shading elements cut the light before it reaches the glass. That is why eaves, balconies, vertical fins and shutters are the most basic tools of a climate-friendly building. They also give a building depth, rhythm and character.

Every orientation wants a different shade. To the south, horizontal elements work best: the summer sun is high and a short overhang cuts it easily, while the low winter sun gets in. To east and west the sun arrives at a low angle; horizontal eaves don’t help here, and vertical fins or movable shutters are needed. The north facade needs the least shading and receives the best light for work.

On the west facade of the Harbour Residences, 2.4-metre-deep balconies are both shade and living space. On the blue glass facade of the Levent Office, slender white vertical lines act as a shading filter against the low morning and evening sun. At the Healing Clinic we calculated the angle of the aluminium fins separately for each facade; consulting rooms receive no direct sun but see the sky. One principle, three answers.

When designing shading we consider not only sun angles but also the view from inside. A row of fins may look elegant from outside but chop the view into pieces from within. So we test the spacing, depth and eye-level position of fins with models and simulations taken from inside. Good shade goes unnoticed indoors; only its coolness is felt.