Lighting is a major consumer of electricity in the United States. According to data from the United States Department of Energy, lighting is responsible for 24% of the primary electricity demand in the building sector, a total of 6.86 quadrillion Btu. And 65% of the lighting energy consumed in the United States is devoted to commercial buildings (D&R International, 2009). According to a nationwide building survey, lighting makes up 38% of all electricity used in commercial buildings, more than any other system (CBECS, 2003).
The energy impact of lighting explains why lighting efficiency is so important. Efficiency improvements in lighting technologies and practice have been dramatic in the past few decades. Increasingly strict energy codes have resulted in substantial energy savings as well as reduced operating costs for building owners as new buildings and retrofits have come on line with upgraded systems.
The drive toward greater lighting system efficiency has been one of the primary motivators for recent changes and improvements in lighting technology, including lamps, ballasts, luminaires and controls. The opportunities for more efficient electric lighting sources, more effective design strategies, greater use of daylight and use of controls to eliminate unneeded light all promise substantial reduction in commercial lighting energy use in the future.