California utility says CFLs burning out faster than expected

The Wall Street Journal reports that in California, compact fluorescent lightbulbs aren't lasting as long as expected. Utilities like PG&E, which has subsidized consumer purchases of CFLs in the state, originally figured a bulb would last more than nine years, but based on experience has lowered that to about six. We've found in our past tests that some spiral CFLs were still shining brightly after 10,300 hours of use. That works out to 3 hours a day for 9.4 years.

The newspaper also reports that field tests show that CFLs have higher burnout rates in bathrooms and recessed lighting, and frequently turning them off and on shortens longevity. For years we've reported that our tests found that CFLs last longer and perform better if they're cycled less often and left on for 15 minutes or more—so they're not ideal for bathrooms. Some can be put into open and fully enclosed recessed cans, but only if they're designed for that use.

Our latest CFL tests found that after cycling on (for 3 hours) and off (for 20 minutes) since early 2009, or 6,000 hours, brightness and warm-up times remained virtually the same as after 3,000 hours of testing. An outside lab has confirmed our result.

While PG&E may be bemoaning the miscalculation, our experts say that you'll save money even if a CFL lasts 6,000 hours rather than the 10,000 the manufacturer claims. A typical incandescent lasts about 1,000 hours and costs 50 cents. You'd need six bulbs and spend about $42 on bulbs and electricity. Or you can buy one CFL and spend $12, electricity included

CFLs aren't for every situation, and they do contain a small amount of mercury and should be recycled. If you're considering CFLs, check our advice on how to choose a lightbulb and our Ratings, available to subscribers, and only buy Energy Star bulbs. Save money by looking for rebates from utilitites, and keep your receipt in case there's a problem.

—Kimberly Janeway