One of the most overlooked energy-saving tools in the work place is the light switch. Lighting accounts for 30-50% of a building's energy use, or about 17% of total annual U.S. electricity consumption. Simply turning off unneeded lights can reduce direct lighting energy consumption up to 45%. If more efficient lighting were to be installed in the majority of places, the US would cut down on particulate emissions of carbon dioxide, sulfur dioxide, and nitrogen oxides by 240 million tons per year.
General Lighting Tips
U.S. Department of the Interior
Greening of the Interior