All About CFLs

CFL Diagram

Inside a CFL

Compact fluorescent lamps, or CFL’s, emit light when electricity excites the mix of gases inside the bulb, creating high energy, invisible, ultra-violet light, which is absorbed by the bulbs fluorescent coating and transformed into visible light.  They are sold in a variety of color temperatures, usually specified in Kelvin (K), providing a range of options to suit your specific lighting needs.  

If you need clean, soft illumination for the kitchen or bathroom, a cool white 3500K– 4100K CFL is a good choice.  And for reading areas and workspaces that require more light, the daylight 5000K – 6500K CFL bulb cast a bright, cool glow that is ideal for detail oriented activities.  

When choosing compact fluorescents, you should always look for bulbs that are ENERGY STAR® qualified because they have been tested to meet stringent performance criteria established by the U.S. Department of Energy and the EPA. 

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Identify Your Fixture Type


To ensure safety and the maximum life of your bulb, look at the package and make sure you have selected the correct bulb for your light fixture. Some CFLs may overheat if placed in a can light or other recessed fixtures. The same can occur with fixtures that are freuently turned on and off.

Color Temperature


Choose a color of light that suits the mood and activity taking place in your room. Measured in Kelvin, this increment determines the color it gives off. A reddish hue considered to be "warm" is denoted as a 2,700K bulb. A "cold" hue with blue tones is reated at 6,000K. Visible light is coolest at higher Kelvin.

Get The Right Size Bulb


With so many bulbs to shoose from, it's important to educate yourself about your fixture and bulb before you purchase. Make sure the bulb fits in your fixture perfectly. Incandescent bulbs are typically 4 inches tall. CFL bulbs vary in size, and can protrude outside of your lamp shade.

Choose Your Desired Brightness (lumen)


Light bulb brightness is rated in lumen (lu). A typical table lamp requires 900lu of light. If using an incandescent bulb for a table lamp, you would use a 60-watt bulb. If using a CFL bulb, a 15-watt bulb would be equivalent.

CFL Bulb Fixture Chart

Table Lamp
Celing Fan
Wall Scounce
Track Lighting
Recessed Can
Vanity Strip
Ceiling Fixture
Outdoor Spot
Outdoor Covered
CFL Twister Bulbs CFL A-Shape Bulbs CFL Globe CFL Decorative Bulbs CFL R20 Bulbs CFL R30 Bulbs CFL R40 Bulbs CFL PAR 38 Bulbs
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Why Use CFL Bulbs?

  • CFLs or compact fluorescent lights, are quickly becoming the low-energy bulb of choice for those concerned with the environment and reducing energy bills.

  • CFLs emit the same amount of light as traditional bulbs, but use %75 less energy.
  • CFL bulbs last approximately 10 times longer.
  • CFLs can fit into most common household sockets and fixtures, making the switch is very easy.
  • CFLs are ENERGY STAR®® qualified and a The Home Depot eco-option.
  • Though the cost of the bulb is slightly higher, longer life span and less energy usage will lower annual costs.
  • CFL ni (non-integrated) bulbs have a separate, permanently installed ballast allowing for a dimmer option with less flickering than other bulbs.
  • CFL lighting can be used to create layers of light for less.

Our Commitment to the Environment

    The Home Depot is committed to energy-efficient products and initiatives whenever possible. Its important to understand recent federal legislation regarding light bulbs and how we can maximize opportunities to protect our environment.

  • The Home Depot is proud to offer free CFL recycling in all U.S. stores.
  • CFL bulbs last approximately 10 times longer.
  • Bring in you expired, unbroken CFLs and look for a bright orange collection unit.
  • As of June 2008, the manufacturing of incandescent reflector lamps has been regulated. Many products are now prohibited by law.
  • The Home Depot now offers acceptable replacement bulbs, please note that these bulbs can provide a different level of light. It's best to replace all bulbs in a room or fixture for consistent look.
  • We recommend CFL and other energy saving bulbs to provide similar light output and meet the new regulations.
  • For special discounts on Professional Contractor Packs of bulk CFL bulbs, please visit this link.

Why should people use CFLs?

Switching to CFL bulbs is a simple, effective way to use less electricity and prevent harmful greenhouse gas emissions.

ENERGY STAR® qualified CFLs use up to 75% less energy, last up to 10x longer, cost little up front, and provide a quick return on investment.

If every home in America replaced one incandescent bulb with an ENERGY STAR® qualified CFL, in one year it would save enough energy to light over 3 million homes and prevent greenhouse gas emissions equal to that of about 800,000 cars.

Do CFLs contain mercury?

CFLs contain a very small amount of mercury sealed in the glass tubing 4 milligrams on average. By comparison, older thermometers contain about 500 milligrams of mercury.

In the past year alone, the average mercury content in CFLs has dropped at least 20%.

Mercury is an essential part of CFLs; it allows the bulb to be an efficient light source.

No mercury is released when the bulbs are intact or in use.

What are mercury emissions caused by humans?

Most mercury emissions caused by humans come from coal-fired electrical power. Mercury can be released into the air, get into water, bio-accumulate in fish and then be mistakenly eaten by humans.

Most mercury vapor inside fluorescent bulbs becomes bound to the inside of the bulb. EPA estimates that if a CFL bulb is broken, the rest of the mercury about 14% is released into air or water when it is sent to a landfill.

If all 290 million CFLs sold in 2007 were sent to a landfill (versus recycled) they would add 0.16 metric tons, or 0.16%, to U.S. mercury emissions caused by humans.

How do CFLs result in less mercury in the environment compared to traditional light bulbs?

Electricity use is the main source of mercury emissions in the U.S. CFLs use less electricity than incandescent lights, meaning CFLs reduce the amount of mercury into the environment.

A 13-watt, 8,000-rated-hour-life CFL will save 376 kWh over its lifetime, thus avoiding 4.5 mg of mercury.

Since CFLs help reduce greenhouse gasses, other pollutants and landfill waste (because the bulbs last longer), they are clearly the environmental winner when compared to incandescent bulbs.

What precautions should I take when using CFLs in my home?

CFLs are made of glass and can break if dropped or roughly handled. Be careful when removing the bulb from its packaging, installing it, or replacing it.

Always screw and unscrew the light bulb by its base and never forcefully twist the CFL into a light socket.

If a CFL breaks in your home, follow the disposal and clean-up recommendations below.

What should I do with a CFL when it burns out?

EPA recommends utilizing local recycling options for CFLs. For an always expanding list of recycling and disposal options, consumers can contact their local municipal solid waste agency, or go to or

If your state or local environmental regulatory agency permits you to put used or broken CFLs in the garbage, seal the bulb in two plastic bags and put it in the outside trash, or other protected outside location, for the next trash collection.

Never send a fluorescent light bulb or any other mercury-containing product to an incinerator.

If your ENERGY STAR® qualified CFL burns out before it should, look at the base to find the manufacturer´s name. Visit their web site, find the customer service contact information and inquire about a refund or replacement. Save your receipts, because these manufacturers are required to offer at least a two-year limited warranty (covering manufacturer defects) for CFLs used at home.

What is mercury?

Mercury is an element (Hg) found naturally in the environment.

Mercury emissions in the air can come from both natural and man-made sources. Coal-fired power plants are the largest man-made source because mercury is released into the air when coal is burned to make electricity.

Coal-fired power generation accounts for roughly 40 percent of the mercury emissions in the U.S.

For more information on all sources of mercury, visit

For more information about compact fluorescent bulbs, visit

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