Definition of Compact Fluorescent Light (CFL)

What Is Community Fluorescent Light?

Compact fluorescent light (CFL) is a more energy efficient and longer lasting light bulb that fits into regular light sockets; making them a functional light source for consumers in most types of light fixtures.

Why use CFL lighting rather than regular incandescent light bulbs? There are several significant money and environmental benefits of using CFLs, including the following:

  • CFL light bulbs use about one-fifth of the energy of regular light bulbs
  • CFLs last 10 times longer than regular incandescent bulbs, so you don’t have to change them as often
  • Unlike regular incandescent bulbs that use 10% of the energy they consume for light and the remaining 90% for producing heat, CFLs do not generally give off heat, making them safer to use and easier on indoor cooling loads

Why are CFLs so spiraled and curly? Most CFLs are made of long, thin tubes that make it possible to generate more light with less electricity. Normally, fluorescent lights are made into long tubes – like the ones found in offices and schools, but in order to get the same length in consumer-friendly bulbs, the tube is coiled up. That said, some electrodeless CFLs have a normal light bulb shape using induction couplings.

Consumers have complained that CFLs provide poor color quality, a common problem with older models of compact fluorescent lamps. However, recent legislation in the US now requires that CFL packaging list the Correlated Color Temperature of any given lamp. Those with a Correlated Color Temperature between 2700K and 3000K provide the best color for everyday use.

Some have expressed concern over the fact that CFLs use mercury, but here are some statistics that should put your mind at rest:

  • Compact fluorescent light bulbs (CFLs) contain about 4 milligrams of mercury, which is far less than the average old-style thermometer (which contains about 500 milligrams) and dental fillings (which often contain 60 to 200 times that of a CFL).[1]
  • Since 50% of electricity used in the US comes from coal-fired power plants, which emitted 50.7 tons of mercury into the air in 2006 (equivalent to 9 billion CFLs worth of mercury), and given that CFLs use 25% less electricity than a standard incandescent light bulb, the net mercury released into the environment is far less with CFLs.[2]
  • Some manufacturers are now making CFLs with as little as 1.4 to 2.5 milligrams of mercury per bulb, which is a significant improvement.[3]


1. Compact Fluorescent Lights Are Safe for Your Home. (n.d.). Retrieved July 1, 2010, from National Resources Defense Council:

2. Compact Fluorescent Bulbs and Mercury: Reality Check. (2007, June 11). Retrieved July 1, 2010, from Popular Mechanics:

3. Information on Compact Fluorescent Light Bulbs (CFLs) and Mercury. (2008, July). Retrieved July 1, 2010, from ENERGY STAR:

Compact Fluorescent Light (CFL) Articles

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