Contrary to what you might have heard, you can still buy most incandescent lightbulbs. But we've found few reasons you should. Our tests of 26 compact fluorescents and 10 light-emitting diodes found that though the newest bulbs might not be perfect, they last longer and use less electricity than traditional incandescent bulbs, and many of the problems of earlier versions have been overcome.
We were testing CFLs, which use about 75 percent less energy and last seven to 10 times longer than regular incandescent bulbs, even before stores began widely selling them. LEDs are the newest choice. They use even less energy than CFLs and are claimed to last for decades. And federal law is set to require most screw-in bulbs to be more efficient by 2014. This report includes our first full Ratings (available to subscribers) of both types. We focused on 60-watt equivalent CFLs and LEDs because those are the most popular types sold in the U.S. Here's what we found:
It usually takes less than a year to recoup the cost of most CFLs, according to our tests, which are based on the bulbs being turned on for 3 hours a day. From that point on you're saving money by using less electricity, about $52 dollars per 60-watt equivalent over a bulb's lifetime. Because of the high cost of LEDs, $20 to $60 per bulb without rebates, they can take four to 10 years to pay for themselves, based on our tests. Even at those prices, you can still save between $65 and $400 over the 18- to 46-year life of the LED compared with an incandescent bulb. But you probably won't save money by switching from a CFL to an LED until the price of LEDs comes down. However, our tests revealed some other reasons that you might want to switch.
After 3,000 hours of testing, the best LEDs were still as bright as the incandescents they replaced. But only about half were as bright as promised. All the LEDs reached full brightness instantly, even at frigid temperatures, providing warm white light that was unaffected by frequently turning them on and off. Energy use matched or exceeded claims, and LEDs don't contain mercury (CFLs do in small amounts). Some LEDs dimmed as low as incandescents. But not all LEDs are good at shining light where you need it. So we've added a light-distribution score to our Ratings.
LEDs are supposed to last 20,000 to 50,000 hours, or about 18 to 46 years when used 3 hours a day. Nearly all the LEDs are still burning brightly after 3,000 hours, and two Cree LEDs we turned on more than a year ago had been continuously burning for more than 9,000 hours at press time. Only four of 100 LEDs stopped working. Those have lower scores for life testing, and we're continuing our testing on all the LEDs.
We asked 19 staffers to use six different LEDs at home for two weeks each and evaluate them using a questionnaire developed by our sensory specialists. Their favorites were the Philips AmbientLED, $40, for table or floor lamps, the EcoSmart LED down light, $50, and the EcoSmart PAR38, $45, outdoor floodlight. But staffers said they wouldn't buy them until prices drop.
The amount of mercury in the bulbs we tested has dropped 60 to 75 percent, compared with the already low levels we found in 2008, without affecting performance. Mercury helps CFLs produce light. And most CFLs contained less than 1 milligram of mercury. The one exception is the EcoSmart covered CFL, and even that has significantly less than Energy Star allows. Given our test results (available to subscribers), Energy Star could consider lowering the mercury cap below 5 milligrams. Nevertheless, spent CFLs should be recycled. Home Depot, Ikea, Lowe's, and some Ace Hardware stores will accept used bulbs. Three CFLs we tested, including the top-rated GE Energy Smart Saf-T-Gard spiral, have a plastic coating that contains mercury and any shards if the bulb breaks. Follow clean-up tips at www.epa.gov/cfl/cflcleanup.html. Sweep up a broken LED and recycle it with other electronic waste because it contains semiconductors.