• Reflected light is characterised by light (sunlight and skylight) that is reflected from the ground: terrain, trees, vegetation, neighbouring buildings etc. The surface reflectance of the surroundings will influence the total amount of reflected light reaching the building facade. In some dense building situations, the light reflected from the ground and surroundings can be a major contributory part of daylight provisions indoors.
The goals of room daylighting are to adequately illuminate visual tasks, to create an attractive visual environment, to save electrical energy and to provide the light needed for our biological needs. A good luminous environment is simultaneously comfortable, pleasant, relevant, and appropriate for its intended uses and users (Lam, 1977).
Daylighting systems can be simple: from combining window design with appropriate internal and external shading (e.g. external awning blind and internal Venetian blind) – to systems designed to redirect sunlight or skylight to areas where it is required (e.g. sun tunnels). More advanced systems can be designed to track the sun or passively control the direction of sunlight and skylight.
Daylighting is inseparably linked to the energy demand and indoor climate of a building. The size and placement of glazing should be determined together with the total energy use of the building and specific requirements for daylighting.