Daylighting is the strategic use of natural sunlight through windows, skylights, and light shelves to illuminate interior spaces and reduce electric lighting energy consumption. Properly designed daylighting systems provide illumination levels of 300 to 500 lux during daylight hours, reducing lighting energy use by 20 to 40 percent. Daylighting also improves occupant productivity and circadian rhythm regulation.
Technical Details
Daylighting design considers window orientation, size, and placement to maximize sunlight penetration while minimizing glare and heat gain. Light shelves reflect sunlight deeper into spaces, while clerestory windows and skylights provide uniform illumination. Photosensor-controlled dimming systems automatically reduce electric lighting when sufficient daylight is available, working with HVAC systems to account for solar heat gain.
Practical Significance
Spaces with quality daylighting show 15 to 25 percent higher worker productivity and reduced absenteeism. When combined with high-performance glazing and shading controls, daylighting reduces cooling loads and peak demand on HVAC systems, lowering operational costs while enhancing visual comfort and connection to the outdoor environment.