In the commercial sector, 75% of electric energy use is for the combination of lighting and air conditioning. These two are strongly interrelated, since lighting is a major contributor to the air conditioning load - so much so, in fact, that many commercial buildings use air conditioning even when the outdoor ambient temperature gets down as low as 45 F. This is due to the fact that regardless of what type lighting is used, 100% of the electricity going into the lamp comes out in the form of heat whether it be in the visible spectrum (and thereby appears as light), or in the invisible part of the spectrum. There are ways of minimizing this effect. One is the use of spot lighting for areas which require high light levels while maintaining an adequate but lower light level in areas such as corridors, reception areas, etc.
