The use of advanced daylighting technologies, such as light pipes, active skylights, and improved windows, may increase the amount of daylight available inside buildings. Perimeter daylighting systems, such as windows, bring daylight about 15 feet into a building.
Core daylighting techniques bring daylight deeper into a building.
However, the application of traditional core daylighting methods, like atria and courtyards, is limited by building height and design. Many building owners are reluctant to turn what could be rentable space into a daylighting atrium. Light shelves are reflective horizontal surfaces that extend from the exterior into the interior of a building. They can extend the useful range of perimeter daylighting on a building's south side to about 25 feet on sunny days. Light shelves can prevent unwanted direct sunlight, which is a source of glare, from entering a space.