Lighting can be provided by skylights which have the potential to displace artificial lighting, improving light quality, reducing heat generation and saving on energy costs.

Why?
A skylight can admit more than three times as much light as a vertical window of the same size. While this performance differential may be reduced in reality (e.g. by a long shaft), in most situations a skylight has the potential to be a very effective day lighting device. Even under overcast conditions use of skylights can result in spaces that can be predominantly day lit with little supplementary artificial lighting required. Additional energy needed for space heating and cooling because of thermal movement through larger window areas will be minimised.

How?
A skylight should be sized to admit just enough light. The smaller the skylight, the less its associated solar heat gain and the less its conduction gains and losses. Skylight spacing is critical in large spaces.