Interior and Exterior Shading
Project or co-planar shading are important variables affecting energy performance in a building.
Exterior and/or interior shading will have impacts on the building's heating, cooling, and lighting, as well as relating it to
the natural environment in terms of access to daylight, ventilation and
Sun control is fundamental for preventing overheating and diffusing
bright sunlight. Sun control solutions should offer shading of direct sun and reduce glare from sky brightness. More advanced approaches improve the daylight illuminance and increase the illuminance deeper into the space.
Fixed Exterior Shading Devices
The sun's seasonal altitude and orientation impact shading device
design. Horizontal shading or light-control elements perform best on
south facades, due to the high sun angles at those orientations.
Vertical elements, in contrast, perform better on east or west
facades—overhangs on the east and west are not effective in blocking the
very low rising and setting sun. Overhangs on the east and west do
provide shade, however, when the sun is higher in the sky.
The classic shading solution for east and west orientations is vertical
fins, however, egg crate, brise soleil, or other architectural
expression can be even more effective in blocking the low sun that
impacts these facades.
Shades and Blinds
While passive controls such as overhangs are fixed, other
controls allow for adjustment or change. Blinds, drapes, and awnings can allow the user to more readily
customize light levels. The effectiveness of sun-control elements
is increased when they are adjustable, to better account for the
inherent daily and seasonal variability of the sun and sky.
Interior shade options range from the traditional roller shades,
venetian blinds, drapes, and blackout screens to blinds located between
the panes of an insulated glazing unit. The finish options are similarly
diverse. Various shading materials and finishes, when matched to a glazing’s visible light transmittance, can
combine to control excess brightness and glare while maintaining a view to the outside.
Exterior shade options also range blinds, screens, roller shades, and
awnings. Similar to the interior devices, exterior shades have diverse,
operability, finish and material options.
Advanced Light Control Systems
Advanced technologies such as automated shading
or light redirection have become integrated solutions for controlling
light and solar heat gain. When used in combination with daylighting controls,
these systems can substantially reduce the electricity loads as well as address the human comfort issues such as comfort and glare.
Daylight typically penetrates a room by 1.5–2 times the window
height. Advanced light control systems, such as light shelves and
prismatic glazing, capture and redirect light even deeper into the space.