Effective Daylighting in Buildings

Lighting accounts for about 20 percent of total electrical energy consumption in the United States or 420-billion Kwh per year. This represents over 5 percent of total national energy consumption and is approximately equivalent, in terms of daily energy consumption, to the total output of the Alaskan oil pipeline. Growth in lighting power demand also places a strain on utility companies, which must site and build new electric power plants. Reductions in lighting energy consumption and associated peak power demand are thus essential elements of a national energy program to reduce our dependence on energy supplies which are associated with political or environmental liabilities.

The winter of 1973-74 saw many lights extinguished in response to an energy shortage. Energy conservation in lighting became associated with delamping, which in turn was reviewed as doing without, and a sacrifice in the quality of living or working environments. Energy conservation practices, however, can provide equivalent or improved visual performance and visual comfort while producing substantial energy and power savings. Four different elements in this process can be identified: 1) substitution of efficient lighting systems and components for less efficient products; 2) improved lighting design practice which eliminates wasteful energy use; 3) improved operation and maintenance of lighting systems; 4) and a return to a partial reliance on natural lighting techniques and practices.