Efficient Lighting
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Control systems

Lighting controls are devices that regulate the operation of the lighting system in response to an external signal (manual contact, occupancy, clock, light level). Energy-efficient control systems include:

Appropriate lighting controls can yield substantial cost effective savings in energy used for lighting. Lighting energy consumption in offices can typically be reduced by 30% to 50%. Simple payback can often be achieved in 2-3 years. Both automatic and manual switching of lamps will adversely affect lamps by shortening their service life. However, this effect is minimal; the energy cost saved by switching lamps off recovers the cost of shortening lamp life whitin a few minutes. Provided that lamps are to be left off for periods of more than two or three minutes it is always cost effective to switch off.

Lighting control systems can combine a number of the strategies outlined here. For example, successful office or hotel corridor installations can have combined centralised time switching, including a lunchtime switch off to reduce lighting use in the afternoon, with daylight linking on luminaires close to the windows and localised switching so that only those areas that are occupied at the time need to be lit. Presence detectors which are fitted within each luminaire can also include daylight sensing. This type of integrally fitted control may solve a problem of difficult shaped spaces or where other linked control is difficult.

It is important that the permanent occupants of a space are aware of the existence of the lighting control system, how it works and how they can interact with it. This is particularly important in retrofit installations, where considerable resistance to the introduction of controls can be produced if the occupants are not consulted and fully informed about the new system.