Underwriters Laboratories

A Compact Fluorescent Lamp, or a CFL, is a lamp designed to use less energy and have a longer rated life than incandescent bulbs. CFLs use about 75 percent less energy than standard incandescent bulbs and can last up to 10 times longer. CFLs are essentially smaller versions of the fluorescent lamps that have been used to provide energy-efficient light for offices, factories and stores for years.

A lamp is a device that generates light when connected to electric power, whereas the term bulb is used to describe the glassware before it is made into a functional lamp. The device that most people call a lamp is actually called a fixture or luminaire in the lighting industry.

Watts and lumens measure different things. The wattage of a light source refers to the electrical power used to energize the CFL while lumen refers to its brightness.

Switching from traditional light bulbs to CFLs enables people to reduce energy use at home and can save consumers approximately $30 or more in electricity costs over each lamp's lifetime. Additionally, CFLs produce about 75 percent less heat, so they're safer to operate and can decrease home cooling costs.

To generate light while using the least amount of electricity, most CFLs are constructed in long, thin tubes. The tubes are then coiled into a spiral - or "twister" style - so CFLs can fit into a lighting fixture designed for incandescent lamps.

CFLs contain a small amount of mercury - approximately 5 milligrams - sealed within the glass tubing. Mercury is a critical component to CFLs. No mercury is released when the lamps are intact or in use. If disposed of properly, mercury in CFLs shouldn't be a safety hazard.

Because CFLs contain a small amount of mercury, the EPA recommends that consumers take advantage of local recycling options for CFLs. The EPA is working with CFL manufacturers and major U.S. retailers to expand recycling and disposal options. Consumers can contact their local municipal solid waste agency directly, or go to www.epa.gov/bulbrecycling or http://www.earth911.org/ to identify local recycling options. Some stores take back used CFLs, in addition to batteries and other potentially toxic household items.

If your state permits you to put used or broken CFLs in the garbage, seal the lamp in two plastic bags and put it into a garbage bin outside, or other protected outside location, for the next normal trash collection. You should not dispose of CFLs in an incinerator.

Energy Star® created a fact sheet that provides recommendations for cleaning up and disposing of a broken CFL. You also can access this list.