Occupant comfort (thermal and visual) requires limits to how hot or cold the interior environment should be. External shading devices are one of a range of strategies available to provide appropriate temperature controls. In the past mechanical systems provided sufficient thermal control. More recently, designers have endeavoured to find passive means to achieve occupant comfort. External shading devices (such as aluminum sunshades) are not really new; vernacular buildings incorporated equivalent passive controls such as simple roof overhangs, a technology which remains effective today. Another example of traditional external shading devices are fabric canopies we associate with shop fronts (often these are operable and can be folded up against the wall).
Typical installations today are usually characterized by a light weight durable solid or louvred panel located along the top of south facing windows. The shade may be horizontal or sloped to shed water and snow. Aluminum Sunshade devices are usually in conjunction with other
strategies such as high efficiency glazing and window coverings.
