There are three basic types of electric lighting systems; regular arrays of lighting, localised lighting and a combination of both, distinguished by the balance between task and building, or ambient luminance.
Local or localised task lighting schemes normally consume less energy than general lighting systems, if care is taken to co-ordinate the lighting layout, task positions and orientation. On the other hand, control systems that integrate daylight with ceiling mounted general lighting can achieve overall lower energy consumption. If visual performance is impaired by poor lighting, poor controls or glare, the system is not effective. In these circumstances, low energy consumption is being achieved at the cost of reduced staff productivity.
The lighting should, therefore, provide a balance between energy efficiency and a sufficient quantity and quality of illumination to perform the visual task efficiently without experiencing discomfort or glare.