Methodology Center Green Tip:
Compact Fluorescent Light Bulbs (CFLs)
Did You Know?
If every American home replaced just one light with a light that's
earned the ENERGY STAR [CFL], we would save enough energy to
light 3 million homes for a year, save about $600 million in annual
energy costs, and prevent 9 billion pounds of greenhouse gas
emissions per year, equivalent to those from about 800,000 cars.
CFLs and Mercury: Some people have expressed concern about
connections between mercury and CFLs. However,
Using CFLs reduces the amount of mercury released into the environment.
 Mercury is found in many rocks including coal. When coal is burned at a utility
power plant to produce electricity, mercury is released into the environment.
 Coal-burning power plants are the largest man-made source of mercury emissions
to the air in the United States, accounting for about half of all domestic humancaused mercury emissions (source: 2005 National Emissions Inventory).
 Using energy-efficient CFLs reduces demand for power,
which in turn reduces the amount of mercury released
into the environment by coal-burning power plants.
CFLs contain very small amounts of mercury.
 Mercury is an essential part of CFLs; it allows the bulb to
be an efficient light source.
 On average, CFLs contain about four milligrams of mercury sealed within the glass
tubing. By comparison, older thermometers contain about 500 milligrams of
mercury – an amount equal to the mercury in over 100 CFLs.
 Manufacturers of fluorescent lighting products are working to reduce the amount
of mercury content in CFLs.
 No mercury is released when the bulbs are intact (i.e., not broken) or in use, but
CFLs release mercury vapor when broken.
Although CFLs reduce environmental mercury, it is still important to
follow your community’s guidelines for recycling them safely.
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