Dome and Sky-light
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.