“Daylighting” is really just the act of illuminating rooms naturally. Any time you’re able to light a room with a window or skylight instead of flipping on a light switch, you are daylighting. It’s that simple.

On the other hand, most designers note that daylighting also involves control. According to the ENSAR Group, a Boulder, Colo.–based architectural and consulting firm that specializes in daylighting, “We see daylighting as the art of bringing natural light into a space in the best way for that space ... understanding what light doesn and how to manipulate it to meet the needs of the people in that space.”

Daylighting solutions can be quite simple or very complex, depending upon the building and the situation. A comprehensive approach, particularly in commercial and institutional building design, must consider many factors: the climate, the sources of natural light, the necessary measures for controlling light, heat gain and heat loss, occupancy and use of the building, and so forth. Such solutions often involve special glazing, coatings, or films; shading and light-reflecting and -diffusing surfaces; special controls that reduce artificial light when it isn’t needed; and more.

Very sophisticated systems may even include sun-tracking mirrors and lenses, light pipes, and fiber-optic cables, but these types of comprehensive daylighting design are not common for houses. “Daylighting isn’t really a term that’s normally applied to a house,” according to the Passive Solar Council. “You can daylight a library or a school, but for a home, true daylighting is pretty unusual.”