Lighting accounts for about five to ten percent of total energy use, per year in the typical home. If a home has extensive outdoor lighting or if any lights are left on all night, the annual lighting cost could be considerably higher. There are several new energy-saving lighting technologies, To understand the energy use of lights – and the savings that can be realized by switching to more efficient lights – we have to understand how light and electricity use are measured. Because we are used to incandescent lamps, which are rated according to their wattage, most of us think of wattage as a measure of light output,Wattage is not a measure of light output. Wattage is a measure of power input. Light output is measured in lumens. A standard “100 watt” bulb uses 100 watts of power to produce about 1300 lumens of light. A Halogen of 70- watt will use 70 watts of power to produce 1300 lumens, where as a compact fluorescent bulb uses only 20 watts of power to produce about the same level of brightness (1300 lumens). And lED bulbs will only use 18 watts to produce the same 1300 lumens.