CFL bulbs, or compact fluorescent light bulbs: energy savings
Commonly referred to as CFLs, compact fluorescent lamps or compact fluorescent light bulbs, the energy-saving bulbs have escaped the stereotype of buzzing, flickery, washed-out lights to become one of the poster children for consumers taking action in the modern green movement. The bulbs, which can replace incandescent, halogen and other electric lights around your house, use between 60% and 80% less energy than their incandescent counterparts, making them an increasingly popular way to cut energy use without having to make any radical changes, like replace your lighting fixtures or rewire your house, in many cases.
Dimmable compact fluorescent light bulbs
In addition to using a fraction of the energy, compact fluorescent light bulbs have a much longer usable life than incandescents, typically lasting between 6,000 and 15,000 hours, compared to 1,000 hours or so for incandescent bulbs. Recent improvements in technology (more details on that in a sec) have improved both the light quality and versatility of CFLs — many now emit a more pleasant “soft white” light and work in dimmable and three-way fixtures. All of this adds up to a bulb that can save the user upwards of $30 over its life and save 2000 times its own weight in greenhouse gas emissions.
How to compact fluorescent light bulbs work?
Instead of a filament lit up with electrical energy, there are two main parts in a compact fluorescent light bulb: a gas-filled tube (also called bulb or burner) and the magnetic or electronic ballast; those with magnetic ballasts tend to flicker more, so electronic ballasts are being used with increasing frequency. When you flip the switch, electrical energy, in the form of an electrical current from the ballast, flows through the gas, causing it to emit ultraviolet light. The ultraviolet light then excites a phosphor coating on the inside of the tube, which then emits visible light. Far out, huh?
courtesy strobist.com
Compact fluorescent light bulbs and mercury
One of the most contentious points about widespread use of CFLs is that they contain small amounts of mercury. However, because CFLs use so much less energy than their incandescent counterparts, compact fluorescent light bulbs are responsible for less mercury contamination than the incandescent bulbs they replaced, even though incandescents don’t contain any mercury. How does that work?
More mercury comes from incandescents than from compact fluorescent light bulbs…how?
The highest source of mercury in America’s air and water results from the burning of fossil fuels, such as coal, at utilities that supply electricity; incandescents burn way more energy, so, on a macro level, require much more energy to be produced. When that energy comes from fossil fuels, like coal (which most of America’s energy does), it causes more mercury to be emitted. Additionally, the National Electrical Manufacturers Association (NEMA) have made a voluntary commitment to cap the amount of mercury used in CFLs: “Under the voluntary commitment, effective April 15, 2007, NEMA members will cap the total mercury content in CFLs of less than 25 watts at 5 milligrams (mg) per unit. The total mercury content of CFLs that use 25 to 40 watts of electricity will be capped at 6 mg per unit.”
Safe mercury disposal from compact fluorescent light bulbs
Still, concerns exist about the mercury escaping from broken CFL bulbs, as safe disposal requires storing the bulbs unbroken until they can be processed. The United States Environmental Protection Agency (EPA) has published guidelines on how to clean up after CFL tube (remember, that’s the “bulb”) breakage and recommends that, in the absence of more specific local guidelines, CFLs be double-bagged in plastic bags before disposal. To properly dispose of the spent bulbs, CFLs need to be recycled by somebody that knows what they’re doing; often, that’s with the retailer or manufacturer from whom the bulb was purchased. If those options aren’t available to you, click on over to earth911.org to find a local CFL recycler. Though the mercury is unlikely to harm you or your family, let’s be clear about this: do not, we repeat, DO NOT toss your CFLs in the trash; putting them there greatly increases the chance of the mercury vapor escaping upon breakage, first exposing you and then the air and water around the landfill to the gas, which is bad news. So be careful with the bulbs, please.
Compact fluorescent light bulbs: the future (for now)
Despite this cautionary tale, CFLs are still the way to go until LEDs become more common (but that’s another post). Manufacturers are improving the quality of light (this is done via the phosphor coating on the inside of the bulb; mono-phosphor lamps emit poor quality light, so the solution is to mix different phosphors, each emitting a different range of light. Properly mixed, a higher-quality light is emitted), and many more options for dimmable CFLs are becoming available; Environmental Defense and One Billion Bulbs both have lists of the dimmable bulbs.
Learn more about compact fluorescent light bulbs
For more information on CFLs, check out Wikipedia’s entry and Energy Star’s resources, which includes a handy, downloadable sheet on proper disposal of CFLs[pdf]. Environmental Defense has a useful widget to help you find a bulb based on what kind (3-way, dimmable, etc.) and where you need it. GE’s FAQ page might help answer your questions, and Eartheasy has a list of the features of different CFL configurations (spiral, triple-tube, dome, etc.).
More CFL bulbs at TreeHugger
Here at TreeHugger, we’ve worn ourselves out keeping up with CFLs; evangelizing their use, watching them in the news, working to dispel the mercury myths andproviding user tips is barely the tip of the iceberg. Check out our How to Green Your Lighting guide for more, or type “compact fluorescent lightbulb” into TreeHugger’s search engine and go nuts. Whatever you do, don’t be a dim bulb: go with CFLs now and the planet and your wallet will thank you later.
The Green Basics series of posts appears regularly here at TreeHugger; we’re writing them to provide basic information about important ideas, materials and technologies for new greenies, or for those who just need a quick refresher.
