CFL

For a given light output, CFLs use between one fifth and one third of the power (measured in watts) of an equivalent Incandescent lamp . Since lighting accounted for approximately 9% of household electricity usage in the United States in 2001,widespread use of CFLs could save as much as 7% from household usage.

Energy efficiency

The average rated life of a CFL is between 8 and 15 times that of incandescents.CFLs typically have a rated life span of between 6,000 and 15,000 hours, whereas incandescent lamps are usually manufactured to have a lifespan of 750 hours or 1,000 hours.Some incandescent bulbs with long rated lifespans of 20,000 hours have reduced light ouput. The lifetime of any lamp depends on many factors including operating voltage, manufacturing defects, exposure to voltage spikes, mechanical shocks, frequency of cycling on and off, lamp orientation and ambient operating temperature, among other factors. The life of a CFL is significantly shorter if it is only turned on for a few minutes at a time: In the case of a 5-minute on/off cycle the lifespan of a CFL can be up to 85% shorter, reducing its lifespan to the level of an incandescent lamp. The US Energy Star program says to leave them on at least 15 minutes at a time to mitigate this problem.

Lifespan

CFLs radiate a different light spectrum from that of incandescent lamps. Improved formulations have improved the subjective color of the light emitted by CFLs such that the best 'soft white' CFLs available in 2007 are subjectively similar in color to standard incandescent lamps.

Compared to general service incandescent lamps giving the same , CFLs use less power and have a longer rated life, but generally have a higher purchase price. In the United States, a CFL can save over 30 in electricity costs over the lamp's lifetime compared to an incandescent lamp and save 2000 times its own weight in . Like all fluorescent lamps, CFLs contain ; this complicates the disposal of fluorescent lamps.

CFL

A compact fluorescent lamp (CFL) , also known as a compact fluorescent light bulb (or less commonly as a compact fluorescent tub