Published: February 15, 2016


Over the last decade building designers have been returning to the centuries-old practice of lighting indoor spaces using natural daylight.

Natural light improves occupant morale and reduces electricity use. While building energy codes now require basic daylighting controls on lights adjacent to windows, designers can utilize more advanced approaches to fully daylight buildings.

Advanced daylighting strategies begin with the basics: glazing placement, size, and properties. Glare could be controlled using shades and overhangs to ensure occupants don’t get too much direct light. To ensure energy savings and occupant comfort, complete a daylight analysis early in the design while changes can be made to the building architecture.

Once a building is naturally lit, controls can be connected to electric lighting to drastically reduce lighting energy. Good lighting control design is more than simply selecting a photosensor. It should include: setting a target light level, deciding between continuous or stepped dimming, and creating zones of light fixtures to control.

Commissioning a daylighting system is an important final step that will often nearly double the savings achieved.

[1] P. Boyce, Daylight Dividends Program, Lighting Research Center, 2004.
[2] Hackel, S., & Schuetter, S. (2013). Commissioning for optimal savings from daylight
[3] Daylighting guidance. (2015).
[4] Rob Guglielmetti, Shanti Pless, and Paul Torcellini. Fourth National Conference of IBPSA-USA, 2010, pp. 301-309
[5] Hackel, S., & Schuetter, S. (2013). Best Practices for Commissioning Automatic Daylighting Controls, ASHRAE Journal.