22 August 2006
Control the electric lighting in response to the daylight by dimming it in
task oriented areas such as offices, conference rooms, classrooms or
turning it off in non-task areas such as circulation and lounge areas.
MAXIMIZE DAYLIGHT POTENTIAL. Building orientation, views, side and
top lighting, shading devices, and selective glazing are all critical to maximizing daylight
potential. All of the following recommendations are for the northern hemisphere. In the
southern hemisphere, recommendations regarding north and south orientations are
reversed. Also, interior spaces should have high ceilings and light reflective surfaces to
allow deep daylight penetration. Provide architectural and manual shading devices for
daylight and view windows. In areas of high threat, lightshelves tend to be discouraged
blast. Refer to the Whole Building Design Guide, Balancing Security/Safety with
Over 60% of existing square footage of interior spaces (within the US) has
access to roofs for top-lighting and 25% of existing national square footage has access
Considerations to maximize daylight potential:
Maximize view windows on the north and south facades.
Provide high ceilings to allow deeper daylight penetration.
Bring daylight high into the space to maximize penetration.
Where possible, consider external light shelves to provide shading for view
Where possible, consider internal light shelves to provide shading for
clerestories and also a surface for reflecting light onto the ceiling.
Provide separate shading devices for daylight windows and view windows.
Utilize selective glazing to maximize visible transmittance (high Tvis) and
minimize solar radiation (low shading coefficient).
Use high reflectance values on ceiling and wall surfaces to balance out the
Avoid daylight barriers such as solid walls near the building perimeter.
Use clerestory and transom glazing to share daylight from perimeter
windows to interior spaces.
Heschong, Lisa, "Daylighting Workshop", Pacific Energy Center, (March 2003).