Daylighting can significantly reduce artificial lighting requirements and energy costs in many commercial and industrial buildings, as well as schools, libraries, and hospitals. Unlike electric fixtures that roll off an assembly line, however, a building is only constructed once, and its light delivery characteristics can't be explored first through a series of prototypes. More and more planning specialists are now incorporating surveys into their research to attempt to quantify productivity gains. We have therefore seen significant technological improvements that make daylighting more attractive.
All light is energy, which is eventually absorbed and turned into heat.
Unfortunately, in the summer this light energy can overheat a building. The south side of a building gets sunlight most consistently throughout the day and the year. This extra sunlight is especially welcome in the winter, when its heating effect is usually desirable. Unfortunately, however, toplighting also has some serious drawbacks. Slides made of a real space and of an accurate model show identical lighting patterns.