A skylight is a light-transmitting structure
that forms all or part of the roof space of a building for daylighting
purposes. Skylights are widely used in designing daylighting for residential,
public, and commercial buildings. Increased daylighting can result in less
electrical lighting use and smaller sized window glazing (side lighting),
saving energy, lowering costs, and reducing environmental impacts. Daylighting
can cut lighting energy use in some buildings by up to 80%. Skylight glazing is
usually glass, although other glazing technologies may be used for solar heat
control. The most commonly seen skylight glazing shapes include rectangular,
circular, oval, diamond, triangular, multi-sided, and tubular.