Frequently Asked Questions

Q. How do CFLs work?
A. Unlike incandescent bulbs which use a filament, compact fluorescent light bulbs (CFLs) give off light when a mixture of gases are exposed to ultraviolet light from mercury atoms.
Q. How much can I save if I use CFLs?
A. On average you can expect to save $40 or more in energy costs over the life of the bulb. CFLs do cost more upfront, but this cost is recovered after using the CFL for 500 hours.
Q. Where is the best place to use a CFL?
A. For the biggest energy savings, replace standard incandescent light bulbs that are used for several hours at a time, like a porch light or an area light.
Q. Is it a good idea to turn CFL bulbs off when I leave the room?
A. Yes! Turning off lights always saves energy. Turning a CFL bulb on and off very frequently (i.e. flipping the switch up and down) will shorten its life. A good rule-of-thumb might be to turn off the lights whenever you leave the room for five minutes or more.
Q. Do CFL bulbs work outdoors?
A. CFL bulbs generally work fine outdoors. They should always be protected against rain and snow.
Q. Do CFLs have a longer life than incandescent bulbs?
A. Incandescent bulbs generally last 500 to 2,000 hours. ENERGY STAR® qualified CFLs are guaranteed for 6,000 hours.
Q. How do I get the special pricing?
A. Visit a participating retailer. Special pricing is valid on ENERGY STAR qualified CFL purchases of 12 CFLs or less.
Q: How can I tell if something is ENERGY STAR qualified?
A: The easiest way is to look at the product packaging. If you do not see a label on the packaging, you should ask the sales clerk to help you.
Q. Do CFL bulbs flicker and hum?
A. Today's ENERGY STAR qualified CFL bulbs turn on almost instantly, are quiet and don't flicker.
Q. I tried CFL bulbs a few years ago and didn't like them. What's changed?
A. Early CFL bulbs were expensive and many people didn't like their performance. Users complained about:

  • Dim light output;
  • Flickering and noise;
  • Funny colors; and
  • Sizes too big to fit in many fixtures.

Today's ENERGY STAR qualified CFLs are a whole new generation of products. They cost much less while offering great performance. You can buy CFLs with as much light output as you want. They turn on almost instantly, are quiet, and don't flicker. Light quality is excellent. CFLs come in a wide variety of shapes, most of which are no larger than the standard bulbs they replace. They also last much longer than standard bulbs.
Q. Do CFL bulbs burn out?
A. A CFL bulb will occasionally burn out. More often, it will continue to operate, gradually producing less light as it ages. However, ENERGY STAR qualified CFLs must produce at least 80 percent of their rated light output at 40 percent of their rated life.
If your CFL bulb fails out of the package or before the manufacturer's warranty expires, you can usually return it to or contact the manufacturer, who is ultimately responsible for warranty claims. Be sure to save the proof-of-purchase and register receipt to document your claim.
Q. How do I dispose of a burned-out CFL?
A. Since CFLs do contain mercury, it is important that you do not throw them in your garbage can, if at all possible. Instead, follow these steps:

  • Visit or call 1-877-EARTH911 to find your local disposal options. You can also contact your local waste management agency for recycling options.
  • If there are no other options, place the CFL in a sealed plastic bag before putting it in your trash.
  • Never send a CFL or other mercury-containing product to an incinerator (some waste agencies incinerate their trash).

Q. What you should know about CFLs and mercury?
A.You should also know that CFLs do contain a small amount of mercury - it's what makes the bulb so energy efficient. But it's important to know that CFLs are safe to use. No mercury is released when the bulbs are in use and they pose no danger when used properly.
Q. What is mercury?
A. Mercury is a naturally occurring metal which has several forms. The metallic mercury is a shiny, silver-white, odorless liquid. If heated or allowed to evaporate, it is a colorless, odorless gas. When liquid mercury is spilled, it forms droplets that emit vapors into the air. However, when mercury emissions deposit into lakes and oceans, they can transform into a highly toxic form that builds up in fish.
Q. What household items contain mercury?
A. Mercury may be found in the following household items:

  • Thermometers, thermostats, barometers and electrical switches
  • "Silver" dental fillings
  • Some light bulbs: CFLs, fluorescent tubes, high-intensity, mercury vapor, high-pressure sodium and metal halide
  • Clock pendulums
  • Athletic shoes, toys and cards that light up or make noise

Q. How do I dispose of a broken CFL?
A. According to guidelines established by the Environment Protection Agency, you can safely clean up the spill yourself if the mercury spill is less than one to two tablespoons and is limited to a small area. If the mercury spill is larger, isolate the contaminated area and call your local environmental agency. The small amount of mercury in a fluorescent light bulb is not likely to cause a health problem, but it still should be cleaned up immediately. Before beginning clean-up:

  • Keep all people and pets away from the area of the spill.
  • If possible, close all doors between the spill and the rest of the house.
  • Turn off all ventilation systems (heating, a/c, fans) unless directly vented to the outdoors.
  • Open windows in the area of the spill.
  • Change into old clothes and shoes that can be thrown away if they come into contact with the mercury.
  • Put on gloves, preferably rubber.

On a smooth surface

  • Carefully use a paper towel to wipe up all glass fragments and fine particles, and then seal in a plastic bag. Do not use a vacuum (which will make the mercury airborne) or a broom (which will break up the mercury droplets and increase exposure).
  • Gather the mercury droplets using two pieces of thick paper or plastic (such as index cards). Use a flashlight held at a low angle to look for additional beads around the room.
  • Either scoop up the beads with the paper or use an eye dropper to collect the beads. Put the mercury and all contaminated materials in a plastic bag and seal.
  • Use duct tape to pick up smaller, hard-to-see droplets. Make sure you also dispose of the tape in a sealed plastic bag.
  • Wipe the area with a damp paper towel and place in the sealed plastic bag.
  • If available, recycle all mercury or throw the sealed plastic bag into your garbage.

On a rug or carpeting

  • Carefully pick up any broken glass and seal in a plastic bag.
  • Use a sharp knife to cut away the entire contaminated area (including carpet/rug backing).
  • Carefully fold the contaminated carpeting/rug so the mercury is trapped inside.
  • Place in a large trash bag along with the knife and seal with tape.
  • If available, recycle all mercury or throw the sealed plastic bag into your garbage.

When you are done...

  • Throw away everything you think may have come into contact with the mercury.
  • Wash your hands or take a shower if you think other parts of your body may have contacted mercury.
  • Keep the area well ventilated for at least 24 hours after the clean-up and continue to keep pets and children away from the clean-up area during that time.
  • Do not pour mercury down the drain. Also, do not wash mercury-contaminated clothing in the washing machine or wear clothes that were contaminated.

For more information on the proper disposal of CFLs or the safe clean-up of mercury spills, please visit: