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Compact Fluorescent Light Bulbs

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The ENERGY STAR Change a Light Campaign is a national challenge to encourage every American to help change the world, one light — one energy-saving step — at a time. You can show your commitment by pledging to replace at least one light in your home with one that has earned the ENERGY STAR.

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Compact fluorescent light bulbs (CFLs) are a good choice for home lighting because they use less energy than incandescent bulbs, produce the same light output, and last up to 10 times longer. Each bulb can save $40 or more in electricity costs over its lifetime.

Where to use CFLs

The federal government's Energy Star guidelines suggest using CFLs in open fixtures that allow airflow, such as table and floor lamps, hanging lamps, wall sconces, and outdoor fixtures. CFLs provide the greatest savings when they're used in fixtures that are turned on for more than 15 minutes at a time. They provide the least benefit if they're used in closets, for example.

Light quality

People are often concerned about the light quality available from CFLs. There are several ways to control for this:

  • Check the lumen rating of the bulb; the higher the lumen rating, the greater the light output.
  • Also check the bulb's kelvin (K) rating. Bulbs with a lower K rating (2,700 - 3,000K) give off a soft, warm light similar to an incandescent and are suitable for living rooms, bedrooms, etc.
  • Bulbs with a higher K rating (3,500 - 6,500K) give off a cooler, white or bluish-white light that may be identified as "bright white" or "daylight." You may want to choose this type of bulb for task lighting.
  • Remember that CFLs can take from 30 seconds to three minutes to reach their full lighting potential after you turn the lamp on.

Choosing the right bulb

To order the right size compact fluorescent bulb, simply compare its measurements to the widest portion and the complete height (including the base or pin) of your existing bulb. Pay special attention to the measurement of the narrowest portion of your existing fixture, such as the narrow portion of the harp in a table lamp.

To select the right bulb for your application, replace your used incandescent bulb with a CFL of equivalent wattage. The table below shows that in general a 3:1 ratio of incandescent to compact fluorescent wattage provides about the same light. CFL manufacturers generally indicate this information on the packaging with wording such as "Equivalent to a 60-watt bulb."

Incandescent Bulb Wattage

25w 40w 60w 100w 150w

Fluorescent Bulb Wattage

7-9w 11w 15-16w 28w 38-39w


CFLs do have a few limitations:

  • They don't perform well at cold temperatures.
  • If they're used in a fixture that vibrates, such as a ceiling fan, that may shorten their life.
  • You'll need to buy specially marked bulbs if you plan to use them outdoors, in closed fixtures, or with dimmer switches.


Mercury is an essential component of CFLs that allows them to operate efficiently. Here are some key facts about mercury:

  • CFLs contain a very small amount of mercury, about five milligrams, sealed within the glass tubing. No mercury is released when the bulb is intact or in use.
  • The power produced by burning coal to light an incandescent bulb releases more mercury into the environment than the power produced to light a CFL (see chart below).
  • Therefore, CFLs are more environmentally friendly even if they are discarded improperly.
  • To gain the greatest environmental advantage from CFLs, they should be recycled.

Read more about mercury in CFLs

Mercury Emissions by Light Source

Over 5-year life

chart comparing mercury emissions for cfl  and incandescent

Recycling and disposal

Although compact fluorescents are fast becoming the most popular form of efficient residential lighting, they are also starting to be seen in our landfills.

Because of their mercury content, it’s best to handle CFLs the same way you would other household hazardous waste products like paint or batteries. They should never be incinerated.

While most states and communities do not require recycling of compact fluorescents, check with your community recycling center or local government about your recycling options. For information on disposal laws and recycling programs in your area, see

If you break a CFL, the Environmental Protection Agency recommends you take the following steps:

  • Open a window to disperse any vapor that may escape and leave the room for 15 minutes or more.
  • Carefully scoop up the fragments and powder with stiff paper or cardboard and place them in a sealed plastic bag; use disposable rubber gloves if available. Do not use your bare hands.
  • Wipe the area clean with damp paper towels or disposable wet wipes and place them in the plastic bag.
  • Place the plastic bag in a second sealed plastic bag and dispose of in the trash. Some states require that broken and unbroken CFLs be taken to a recycling center.
  • Do not use a vacuum cleaner or broom to clean up the broken bulb on hard surfaces.
  • For carpet cleaning and additional information on CFL disposal, see the Energy Star CFL page.


compact fluorescent


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