Lighting accounts for the largest portion of a commercial building's electricity bill and a significant portion of the total energy bill. Lighting consumes close to 35 percent of the electricity used in commercial buildings in the United States. It affects other building systems through its use of electricity and its production of waste heat.

An efficient system of lighting sources, fixtures and controls can reduce energy use, give businesses more flexibility in the sizing of HVAC and electrical systems, and may even improve worker productivity.

Waste heat

Lighting systems produce large amounts of heat as well as light. Lighting uses about 18 percent of the electricity generated in the U.S., and another 4 to 5 percent goes to remove the waste heat generated by those lights.

Energy-efficient lighting adds less heat to a space per unit of light output than inefficient lighting. With good design, lighting energy use in most buildings can be cut at least in half while maintaining or improving lighting quality. Such designs typically pay for themselves in energy savings alone within a few years.

By reducing waste heat, efficient lighting also reduces a building's cooling requirements. Consequently, the existing cooling system may be able to serve future added loads.