Daylighting is the controlled admission of natural light—direct sunlight and diffuse skylight—into a building to reduce the reliance on electric lighting and to save energy.
By providing a direct link to outdoor illumination, daylighting helps create a stimulating, pleasant, and productive space while reducing total energy costs by as much as one-third.
Daylighting involves the design and type of windows and skylights as well as fenestration, which means the location of them in the building. Glare remediation devices such as blind or shades are part of the solution. The National Fenestration Rating Council web site provides a wealth of information including a directory of certified products and a list of companies who participates in its programs to get their products rated.
The science of daylighting design is not just how to provide enough daylight to an occupied space, but how to do so without any undesirable side effects. Beyond adding windows or skylights to the space, it involves carefully balancing heat gain and loss, glare control, and variations in daylight availability.
For example, successful daylighting designs will carefully consider the use of shading devices to reduce glare and excess contrast in the area. Additionally, window size and spacing, glass selection, the reflectance of interior finishes, and the location of any interior partitions must all be evaluated.
A daylighting system consists of systems, technologies, and architecture. While not all of these components are required for every daylighting system or design, one or more of the following are typically present:
- Daylight-optimized building footprint
- Climate-responsive window-to-wall area ratio
- High-performance glazing
- Daylighting-optimized fenestration design
- Skylights (passive or active)
- Tubular daylight devices
- Daylight redirection devices
- Solar shading devices
- Daylight-responsive electric lighting controls
- Daylight-optimized interior design (such as furniture design, space planning, and room surface finishes).