Providing the light needed for illumination from light sources with higher light efficacy is the first condition of energy saving in illumination. Light sources with higher efficacy factor give more light flux per unit power. Therefore, an illumination conducted by using sources with higher effectiveness factor need less light source for the same level of illumination, and less power is consumed. For example, factory interior illumination with high-pressure mercury-steam lamps can ensure up to 43% saving compared to florescent lamps. Efficacy factors belonging to light sources can be seen in the comparative table for lamps.
Luminaires cannot distribute to the area effectively all beams that the light sources inside them radiate. Some of the beams are absorbed by reflective surfaces or cannot be reflected to the targeted area as these surfaces are not corretly positioned. High-quality high-efficiency luminaires with a properly designed reflector must be used in order to avoid this problem.
Today discharge lamps which are among the basic elements of efficient indoor and outdoor illumination generally need such components as ballasts, starters, igniters etc. active power loss of such auxiliary components as ballasts, which are especially on continuously, has significant impact on the efficiency of the system. For example, ballasts which lose less pwer (low-loss magnetic or electronic ballasts) or busbar canals insted of classical fixtures can improve system efficiency.
Energy can be saved by using systems which ensure sufficient illumination in times when it is needed. These systems can turn off the lamps based on the signals they receive when there are no people, they also turn off the lamps when light coming into the environment increases, or they can perform dimming automatically.
With these systems which turn off the light when no illumination is neded, or which perform dimmimg so as not perform excessive illumination, up to 40% power saving can be achieved.
In a design which is based on energy saving surfaces in the relevant area (walls, ceiling, floor etc.) must be painted or covered with colors with high reflection lactor. Required illumination must be handled for each relevant surface. For example, if 1000 lux illumination is needed for working surface in an pffice illumination, this does not mean that the entire office must be illuminated at 1000 lux level.
As for the interior environments which do mot receive light from outside during daytime, illumination by conveying through fiber optic cables or reflective pipes.
Using solar energy systems which receive electrical power from solar power, store the electrical power they obtain, and use this stored power for illumination in the absence of sunlight.
The purpose of energy saving is decreasing energy input; this purpose can be achived by prov.ding this energy from renewable sources. Small-size wind-solar hybrid energy systems which can be installed on the roofs of houses can make sure that the emergency illumination needs can be met.