Lighting > Light Shelves

Existing Conditions

A large room has windows facing south, which is an idea situation for using natural light.

Retrofit Conditions

A light shelf could be installed to extend the natural lighting further into the room. This should be coordinated with photo-sensing light controls to maximize the natural light when it is available.

Further Benefits

The quality of light will increase significantly due to the wider spectrum of light in the room, and will increase worker productivity. The shelf will reduce the glare from direct sunlight near the window and distribute it more evenly across the room.

Application Details

The shelf should be located on the exterior of the building, tilted upward at approximately 30º. Consider using a shelf with a parabolic curve to better utilize the shelf during all seasons.

If the window is to be replaced or is new, consider placing two windows in the space. The window above the shelf is clear for daylight harvesting, and the window below the shelf is tinted for glare control.

Issues and Concerns

During the cooling season, light shelves may need to be blocked to reduce solar heat gains when the cost to cool the space exceeds the benefit of natural light.

References

Analysis