Compact Fluorescent Light (CFL) F.A.Q.'s

Buying Guide

CFL stands for compact fluorescent lamp, and it is a small fluorescent light bulb that uses 75% less energy than a traditional incandescent bulb and can be screwed into a regular light socket. Don't let the fact that it is fluorescent turn you off! ENERGY STAR qualified CFLs must pass extensive testing to ensure they produce only the highest quality light.

Qualified bulbs labeled "warm white" or "soft white" produce light like typical incandescent light bulbs. CFLs that have a cooler color (similar to bright white incandescent bulbs) are usually labeled "bright white" or "daylight" on the product packaging. More on choosing the right CFL color for you.

Can I turn my Compact Fluorescent Lights (CFL) on and off frequently?

Turning a CFL on and off frequently can shorten its life. To take full advantage of the energy savings and long life of ENERGY STAR qualified CFLs, it is best to use them in light fixtures you use the most and are on for at least 15 minutes at a time. Good locations include outdoor light fixtures, indoor fixtures in the living room, family room, kitchen, bedroom, recreation room, etc. This is not to say you should leave your lights on all day if you use ENERGY STAR qualified CFLs. It is still a good habit to turn the lights off when you leave the room for an extended period of time.

Can Compact Fluorescent Lights (CFLs) be used in recessed cans, outdoor lights, or track lighting?

Yes! Always read the packaging of the CFL to be sure of its proper application, but there are a wide variety of ENERGY STAR qualified CFLs that are designed for use in most fixtures in your home or business. Product types include:

  • Incandescent shape (or A-shaped) and Globes, both are good in fixtures where the bulb is exposed or in fixtures with clamp lamp shades
  • Reflectors are intended for non-dimmable track lighting and recessed cans, and some weather protected outdoor spot lights
  • Candle shapes can be used in some porch lights, in wall sconces and in some chandeliers
  • Spirals, and mini-spirals are getting smaller and smaller in size and can be used in almost any fixture, especially table and floor lamps with harped shades
  • There are a few qualified 3-way and dimming CFL models that can be used for 3-way fixtures or in dimmable recessed cans or CFL track lighting. Search for CFL features you want in our "advanced" product search.

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

Because CFLs contain a small amount of mercury, EPA recommends that consumers take advantage of local recycling options for used fluorescent light fixtures (CFLs), where available. Consumers can contact their local municipal solid waste agency directly, or go to www.lamprecycle.org and click on Lamp Recycling policy

to identify local recycling options. If your state permits you to put used or broken CFLs in the garbage, seal the CFL in two plastic bags and put into the outside trash. CFLs should not be disposed of in an incinerator.

ENERGY STAR qualified CFLs have a two-year warranty. If the bulb has failed within the warranty period, return it to your retailer.

Can ENERGY STAR qualified CFLs be used with dimmer switches?

Yes, certain ENERGY STAR qualified CFLs are made to work on dimmers. Be sure to check the fine print on the back of the packaging for the proper applications to see if there are any restrictions on the product's use. Dimming an ENERGY STAR qualified CFL that is not designed to work with a dimmer switch can shorten its life significantly.

To find a list of dimmable CFLs, visit the ENERGY STAR CFL Advance Search and search on "Dimmable CFL." Your local hardware store may not stock a wide variety of dimmable CFLs, so if you are looking for a specific wattage or bulb type, you may want to try to purchase it online. The ENERGY STAR Store Locator lists local and online retailers who sell CFLs.

If you have additional questions or concerns about your ENERGY STAR qualified CFL, please e-mail cfl@energystar.gov.

My light fixture can is for a 75 watt bulb, if I use a CFL can I use the equivalent of 100 watts?

The watt rating on the fixture is a description of how much electricity the internal wiring of the fixture can accept safely. A watt is a measure of power consumption. Since the light fixture can accept up to 75 watts of power, you can use any light bulb with a rated wattage of 75 or less. While you can use a 75-watt equivalent CFL, if you want more light in this fixture, then yes, you can use a CFL that produces as much light as a 100-watt incandescent. A 100-watt CFL will typically use between 23 and 30 watts of power much less than the 75-watt rating of the fixture. That's the great thing about ENERGY STAR qualified CFLs - you get more light for less power!

What are "long life" incandescent light bulbs?

While a "long life" bulb does last longer than a standard incandescent bulb, it still uses a lot of energy and it doesn't last as long as a Compact Fluorescent Lights (CFL). A long life 60-watt incandescent bulb usually lasts for 2,000 hours, but an equivalent 13-watt ENERGY STAR qualified CFL will last 6,000 hours or more, and use 75% less energy. ENERGY STAR qualified CFLs help you save money in energy and household costs and you won't have to buy and change bulbs as often.

I want to replace my 60-watt incandescent light bulb. How do I select the best CFL?

Finding an ENERGY STAR qualified CFL that will put out the same amount of light as your current incandescent bulb is easy. Manufacturers include product equivalency information on the packaging to help consumers choose a bulb that produces enough light. For example, if you are looking for an ENERGY STAR qualified light bulb to replace your 60-watt incandescent, look for words like "Soft White 60", or "60 Watt Replacement" on the packaging.

You can also refer to the chart below to as a guide for selecting the right bulb. A watt is actually a measure of power consumption. When purchasing a light bulb, what you are really after is light output, which is measured in lumens. When you purchase a 60-watt incandescent bulb, you are getting about 800 lumens. By selecting a 13-watt compact fluorescent bulb instead, you can still get 800 lumens, but it requires much less power.

Energy Use for Incandescent Light Bulbs (Watts) Minimum Light Output (Lumens) Energy Use for common ENERGY STAR qualified CFLs (Watts)
25 250 4 to 9
40 450 9 to 13
60 800 13 to 15
75 1,100 18 to 25
100 1,600 23 to 30
125 2,000 28 to 40
150 2,600 30 to 52

Be sure to look for the ENERGY STAR mark on the product packaging. ENERGY STAR qualified CFLs must pass product quality and performance tests to earn the ENERGY STAR, so CFLs with the ENERGY STAR mark are a notch above the others.

Also, make sure you choose the right compact fluorescent light fixtures for the right place, and that you read the CFL packaging. For example, for popular recessed ceiling fixtures (also called recessed cans), choose a CFL made for this application. In addition, only a handful of CFLs currently work well on dimmer and remote switches, or come with a 3-way switching feature. Read the packaging to be sure you properly place your new CFL light fixtures to get the best performance.

Does extreme cold or humidity affect CFLs?

Extreme temperatures can affect CFLs. Some CFLs can be used outside in temperatures down to –10 degrees Fahrenheit and up to 120 degrees Fahrenheit, though when it is very cold they may take longer to reach full brightness. If you are looking for an outdoor fluorescent light fixture that is weatherproof and can be used outside, check for "weatherproof" on the label before installing it in your outdoor spot light.

Why choose ENERGY STAR qualified CFLs over a non-qualified CFL?

ENERGY STAR qualified CFLs are different than other CFLs on the market because they have been tested to meet stringent performance criteria established by the U.S. Department of Energy and the U.S. Environmental Protection Agency. The criteria ensure that all CFLs earning the ENERGY STAR meet minimum lifetime and efficacy requirements, and are within maximum allowed product start and warm-up times. Manufacturers are also required to label the product if the light output is different than that of a soft white incandescent. If you choose a CFL that is not ENERGY STAR qualified, you might not get the performance you were looking for.

I've noticed some CFLs need a few minutes to warm up, or reach full brightness...

By choosing an ENERGY STAR qualified CFL, you are assured that it will turn on in less than a second, and reach at least 80% of full light output within 3 minutes. If the CFL doesn't have the ENERGY STAR, both start time and warm up time could be much longer.

Additionally, many lighting manufacturers offer instant on CFL bulbs. Some spiral and mini-spiral (mini fluorescent light) products incorporate "instant-on" technology in their products and display this feature prominently on the product packaging. Some covered or reflector CFLs actually do take longer to warm-up, but the trade off is that they last longer than regular CFLs. ENERGY STAR qualified CFL products that are covered (like incandescent shaped, reflectors, globes, candles) have a higher operating temperature so they require a compound called amalgam to perform properly. This compound actually increases the bulb life and the light output! The one trade off is that these CFLs cannot offer "instant full brightness." The CFL will turn on, but may take up to three minutes to warm-up to reach full light output.

How can I find the right colored CFL light bulbs?

Just like incandescent bulbs are labeled soft white, cool white, bright white, etc., you will find ENERGY STAR qualified CFLs labeled soft white, cool white, or daylight (similar to bright white). When selecting a new CFL, it is a good idea to use the same color type as the incandescent you are replacing. Another way to do this is to look for the scientific color designation known as correlated color temperature (CCT) on the packaging: 2,700K, 3,000K, 5,100K, etc. Lower CCT numbers mean the light will be warmer white (yellowish), while higher numbers mean it will be cooler light (bluish). Matching these numbers gets you consistent color. The majority of CFLs available in the market offer soft or warm white light (2700K–3000K), which is comparable to an incandescent bulb. When changing out multiple bulbs in one room, select ENERGY STAR qualified CFLs with the same color and the same manufacturer to help ensure more consistent light color.

More information on CFL colors.

Will ENERGY STAR qualified CFLs fit into my existing fixtures?

Is it possible to find a CFL incandescent equivalent that can replace regular, incandescent bulbs in almost any fixture. They come in a wide variety of sizes and shapes including globe lamps for your bathroom vanity, chandelier bulbs, lamps for recessed downlights (now commonly found in kitchens, hallways, and more), and larger or more compact standard light bulbs.

Check the packaging of the CFL to ensure that it may be used in an entirely enclosed fixture. Additionally, some ENERGY STAR qualified CFLs are specifically designed to provide dimming and 3-way functionality -- these options will be identified on the products' packaging.

More information on ENERGY STAR qualified CFLs.

How should I clean up a broken compact fluorescent light bulb (CFL)?

Because CFLs contain a small amount of mercury, EPA recommends the following clean-up and disposal guidelines:

  1. Open a window and leave the room (restrict access) for at least 15 minutes.
  2. Remove all materials you can without using a vacuum cleaner.
  3. Wear disposable rubber gloves, if available (do not use your bare hands).
  4. Carefully scoop up the fragments and powder with stiff paper or cardboard.
  5. Wipe the area clean with a damp paper towel or disposable wet wipe.
  6. Sticky tape (such as duct tape) can be used to pick up small pieces and powder.
  7. Place all cleanup materials in a plastic bag and seal it.
  8. If your state permits you to put used or broken CFLs in the garbage, seal the CFL in two plastic bags and put into the outside trash (if no other disposal or recycling options are available).
  9. Wash your hands after disposing of the bag.
  10. The first time you vacuum the area where the bulb was broken, remove the vacuum bag once done cleaning the area (or empty and wipe the canister) and put the bag and/or vacuum debris, as well as the cleaning materials, in two sealed plastic bags in the outdoor trash or protected outdoor location for normal disposal.

Do CFLs contain mercury?

CFLs contain a very small amount of mercury sealed within the glass tubing – an average of 5 milligrams, which is roughly equivalent to an amount that would cover the tip of a ball-point pen. No mercury is released when the bulbs are intact or in use. By comparison, older thermometers contain about 500 milligrams of mercury. It would take 100 CFLs to equal that amount.

Mercury currently is an essential component of CFLs and is what allows the bulb to be an efficient light source. Many manufacturers have taken significant steps to reduce mercury used in their fluorescent lighting products. In fact, the average amount of mercury in a CFL is anticipated to drop by the end of 2007, thanks to technology advances and a commitment from the members of the National Electrical Manufacturers Association.

Because CFLs contain mercury, they should be disposed of properly.

What precautions should I take when using CFLs?

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 lamp by its base (not the glass), and never forcefully twist the CFL into a light socket. Because CFLs contain a small amount of mercury, follow proper clean-up recommendations if a CFL breaks in your home. Used CFLs should be disposed of properly.

What is a watt? What is a lumen?

A watt is the measure of power consumption, and is the common way incandescent light bulbs are identified -- for example 60-watt, 75-watt and 100-watt. When purchasing a light bulb, however, what you really should look for is lumens, which is the measure of light output. When you purchase a 60-watt incandescent bulb, you are getting about 800 lumens. By selecting a 13-watt ENERGY STAR qualified CFL

instead, you can still get 800 lumens, but it requires much less power.

What is the difference between the coil design and the CFLs that resemble a traditional lightbulb?

There are a handful of differences between the coil or "spiral" CFLs and the CFLs that resemble a traditional lightbulb (A-line shape). The first difference is the amount of light each will produce. Most times, a CFL that looks like an incandescent light bulb is really the "coil" shaped CFL with a plastic or glass cover. This cover will slightly reduce the amount of light that is produced. If you compared a 14W bare spiral CFL and a 14W "incandescent" shaped CFL, the bare product will provide more light for the same wattage. Also, bare CFLs usually have longer lifetimes than covered products.

Second, most bare spiral CFL products will perform like incandescent light bulbs - they will turn on instantly and provide full brightness. Covered CFLs may take slightly longer to reach full brightness.

The last difference is the price - covered CFLs generally cost slightly more than bare spiral because of the additional materials required to manufacturer the products.

Ordering ENERGY STAR Publications

Go to the ENERGY STAR Publications web page to place an order for brochures, Annual Reports, Fact Sheets, Booklets and more. All publications can also be downloaded.

Why should people use CFLs?

Switching from traditional light bulbs to CFLs is an effective, accessible change every American can make right now to reduce energy use at home and prevent greenhouse gas emissions that contribute to global climate change. Lighting accounts for close to 20 percent of the average home's electric bill. Changing to CFLs costs little upfront and provides a quick return on investment.

If every home in America replaced just one incandescent light bulb with an ENERGY STAR qualified CFL, it would save enough energy to light more than 3 million homes and prevent greenhouse gas emissions equivalent to those of more than 800,000 cars annually.

How is an ENERGY STAR qualified CFL different from the light bulbs I grew up with?

You probably had incandescent light bulbs in your home, and probably do now, too. Incandescent light bulbs work by heating a tungsten filament, or wire, until it glows. This is what produces the light you see. Unfortunately, 90% of the energy used to generate that light is wasted as heat, making incandescent bulbs a very inefficient way to light your home. ENERGY STAR qualified CFLs, on the other hand, create a chemical reaction among gasses located inside the glass tube, causing phosphors to illuminate. This is a much more efficient way of producing light, and means CFLs produce far less heat.

What's the difference between ENERGY STAR qualified and standard fixtures?

Most ENERGY STAR qualified fixtures come with pin-based compact fluorescent lamps that are tested to last at least 10,000 hours (about 7 years, on average) versus standard screw-in bulbs which last about 1,000 hours or up to 1 year. Some ENERGY STAR qualified outdoor fixtures will accept an incandescent light bulb because they save energy through a motion sensor and/or a photocell that turns the light on only when someone is present or on and off at night and in the morning. Qualified fixtures come in hundreds of popular styles, including table, floor and desk lamps and in hard-wired styles for ceilings, walls, bathroom, kitchen, dining room, and outdoors.

Replacement pin-based CFL bulbs can be found at most hardware or home improvement centers, at lighting showrooms, and on the Internet.