Even a compact fluorescent light bulb that burns out prematurely uses less electricity while you use it -- but you may or may not break even. The environmental advantage of a compact fluorescent bulb also depends on its lifetime, because incandescent light bulbs require fewer resources and electricity to manufacture. We found loads of statistics estimating the environmental savings of switching to compact fluorescent light bulbs, but again -- it depends on your situation and your care in selecting and using the bulbs. Here are some things experts say to consider:

  • Bulb lifetimes are only an average, and only under ideal conditions. There's been a lot of complaints that compact fluorescent light bulbs don't last nearly as long as they're supposed to. Indeed, the majority of comments we read were from people who expected them to last longer. Light bulb hour ratings are an average. So if a bulb's rating is 10,000 hours, that means that in lab tests half of the bulbs lasted longer than 10,000 hours, while half didn't last that long. Still, with incandescent bulbs rated for about 1,000 hours, even CFL bulbs that last only half as long as they're supposed to result in a savings, particularly now that CFL bulbs have come down so much in price.
  • CFLs can save you money. You'll probably save some money by switching to good compact fluorescent light bulbs, as long as you use them in the right fixtures, keep them on for at least 15 minutes at a time and exchange any defective bulbs without paying return shipping. So it's reasonable to switch from incandescent light bulbs now, before their mandated phaseout in 2012. For use with dimmer switches, new energy-saving halogen light fixtures are a better bet, though dimmable CFL bulbs are now available.
  • LED light bulbs could be the future. Experts agree that LED light bulbs will be superior to compact fluorescent light bulbs in many ways -- eventually. For now, they're worth considering for certain purposes, but they are too expensive and dim for most settings.
  • Pay attention to color temperature. Except for halogen light bulbs, whose light is usually white, each type of light bulb is available in various color temperatures, usually specified in degrees Kelvin (K). Most light bulbs range from a warm 2,700K through various steps of cooler, bluer, to a very bluish-white 5,000K, often called full spectrum.
  • Look for lumens, not wattage. Because the amount of light produced per watt by the different light bulb technologies now available, new packaging regulations that will soon go into effect will require bulbs to carry their lumen rating, which is a measure of light output.
  • Consider the warranty. Light bulb warranties are usually specified in hours or years, but retailers and manufacturers vary a great deal in how they handle warranty claims. As many owner-written reviews testify, a light bulb warranty doesn't help much if the company requires you to pay shipping to return defective bulbs. Retailers may or may not accept returns. Also, many light bulbs are designed for specific kinds of light fixtures, and using them with a dimmer switch, with an enclosed or recessed fixture or in a damp setting -- even with the same medium-base screw-in socket -- may void the warranty.
  • Starting time isn't the same as run-up time. Compact fluorescent light bulbs must start within one second to earn Energy Star certification, but may still take up to 30 seconds or so to attain full brightness. LED, halogen and incandescent light bulbs start so fast that the delay is imperceptible. While you are first getting used to compact fluorescent light bulbs, the delays can be disconcerting. Reviews warn that in a few situations the delays can be dangerous -- for example, if you depend on instant light for safety on stairs.
  • Most dimmer switches are designed for use with incandescent light bulbs. Reviews warn that even when labeled "usable with dimmers," it's possible that a compact fluorescent light bulb won't work with your dimmer switch. The same is true of three-way light fixtures: A three-way compact fluorescent light bulb may or may not work. Your best bet is to replace incandescent light bulbs first in ordinary light fixtures that get plenty of airflow and that stay on for hours at a time. Both heat and cycling on and off often can drastically shorten the lifetime of compact fluorescent light bulbs.

Light bulbs and other health concerns

Full-spectrum lighting isn't the only health concern that various experts have raised about light bulbs. Other concerns include electromagnetic fields (EMFs) and the possible release of toxic chemicals, including mercury, if a compact fluorescent light bulb is broken. We found some studies of both risks. UV light is of less concern, because reviews say that light bulbs emit relatively little UV light compared with sunshine.

Although there's evidence that exposure to electromagnetic fields is hazardous for children -- with a connection to leukemia rates -- it's not clear whether or not EMFs pose a problem for adults. Apparently some people are more sensitive to such fields than others; if you've ever gotten a headache from one or more light fixtures or bulbs, you're apt to be one of them. Incandescent light bulbs don't emit a high electromagnetic field, but some compact fluorescent light bulbs do -- certainly the ones that use an iron-core electromagnetic ballast. If EMFs are a concern, select a bulb with a solid-state electronic ballast.

In addition to mercury, fluorescent light bulbs contain other toxic materials. Most contain cadmium, lead, hexavalent chromium and polybrominated biphenyls. Hence, reviews say it's a good idea to familiarize yourself with the safest cleanup procedure when buying compact fluorescents (or any fluorescent light bulb, for that matter).

Of course, disposing of unbroken defective or used fluorescent light bulbs is a major environmental concern. A few localities have ample recycling facilities in place, but proper disposal of hazardous light bulbs is still a real problem in many areas. You can find links to information about how to properly dispose of CFLs in the Useful Links section of this report.

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