What is the efficiency rating for a 60-watt incandescent bulb?
From Olga Answer: There are various ways of defining “efficiency;” that’s what we’ll try to do here. First, remember that like any electrical device, an incandescent light bulb is nearly 100 percent energy efficient. That is, nearly all of the energy coming into the light bulb is used in some way; it is not destroyed or lost, although some may become unavailable for further use. So while the quantity of energy is the same, the quality may be different. Light bulbs, for example, don’t use all of their energy as light. Incandescent bulbs use electricity to produce only about 10 percent light; the remaining 90 percent of their output is as heat. That’s not a very efficient use of a light bulb! Compact fluorescent bulbs (CFLs) on the other hand, produce only about 30 percent heat and 60 percent light. To determine energy use and savings of various types of bulbs: • Look at the lumens/watt ratio for any bulb to see how much light you get from the bulb. A lumen is a measure of light and watt
