Annex 7.A Example options of measures for the control of solar gain
Solar shading should be designed to reduce summer time overheating and allow passive solar gain during winter months. Effective solar shading design should not reduce natural lighting within a room to the extent that artificial lighting is required. External shading devices are the most effective as they deflect solar radiation before it enters the building.
Horizontal devices on south facades provide the most effective shading without compromising natural daylight, however this type of measure is not suitable for east and west facades as the angle of the sun is too low. Vertical fins and adjustable devices such as sliding and rotating shutters are best suited to east and west facades. For optimum indoor thermal comfort designers should consider combining effective solar shading with night time cooling through the use of inward opening hopper windows or vents.
Figure 7.1. Horizontal overhangs
Horizontal overhang or window reveals are best suited for south facing openings, the total shading depth should be around 50% of the window height and extend no greater than 1500mm for optimum effectiveness. Measures can provide up to 75% solar gain reduction.
Figure 7.2. Horizontal louvres
Horizontal louvres and shutters (sliding or rotating) combined with a horizontal overhang can be used on south facades. Measures can provide up to 90-95% solar gain reduction.
Figure 7.3. Shutters
Shutters (sliding or rotating) can be used on south, east and west facing facades. Lockable shutters allow secure night time cooling and inward opening windows.
Figure 7.4. Vertical fins
Vertical fins (adjustable or fixed) combine with a horizontal overhang are best suited for east and west facades. Measures can provide up to 85-90% solar gain reduction.
Figure 7.5. Awnings
Awnings or roller shades can be used on south, east and west facades. Measures can provide up to 60-75% solar gain reduction.
External shading devices should be considered in the first instance. However where external shading devices cannot form part of the external fabric for reasons such as a planning restrictions, internal shading devices such as curtains and blinds can be used. These measures are generally not as effective as external shading devices as they absorb part of the solar radiation within the room or space.