A skylight is a structure that allows light on the roof to travel to the interior of a building. Skylights are particularly useful in spaces that do not receive much natural daylight. For example, walk-in-robes, hallways and rooms next to patios or verandahs.Skylights are a pleasant, environmentally friendly solution to brightening your residential or commercial premises. Using natural light rather than electricity as a light source saves energy and can dramatically cut your electricity bills.