The phase-out of inefficient bulbs starts in January 2012 with 100-watt bulbs that use too much energy. Fans of 100-watt incandescent bulbs like the added brightness they provide, but when it comes to their energy-saving replacements, you can't have it all. Based on Consumer Reports tests of seven compact fluorescent lightbulbs and two halogen bulbs, to save energy you may have to sacrifice some brightness.
Though both types of bulbs use less energy than an old- fashioned 100-watt incandescent, a CFL can save you $100 or more on electric costs per bulb over its lifetime, compared to only around $3 to $8 per halogen bulb. But the halogen bulbs remain brighter than CFLs and about as bright as a 100-watt incandescent. Here are the details:
All bulbs lose brightness over time, even old fashioned incandescents. But in our tests even the brightest CFLs were roughly only 1,400 lumens after 3,000 hours of testing. Energy Star recommends 1,600 lumens or more to replace a 100-watt bulb when new, though it allows lumens to drop off as CFLs age. None of the bulb’s lumen output dropped more than Energy Star allows. (Lumens measure brightness; watts just indicate energy use. Both numbers are on the Lighting Facts Label on the package.)
"The challenge in making a brighter CFL is to get the spiral glass wrapped in a way that light is diffused and doesn't just bounce around the inside of the bulb, without making the bulb larger than the incandescent it's replacing," explains Terry McGowan, director of engineering at the American Lighting Association, a trade group.
Brighter is not necessarily better. Brightness becomes especially important as you age—starting roughly in your 40s to early 60s—and the lens in your eye becomes more rigid and then cloudier. When that happens, more light is needed to provide contrast, says R. Linsy Farris, M.D., a professor of clinical ophthalmology at Columbia University. So we asked 12 staffers, age 40 and over, to sit at a desk and read for a couple of minutes under two different CFLs from the same brand, a new one and one that had undergone 3,000 hours of testing and was roughly 200 lumens dimmer. About half preferred the dimmer bulb for reading.
But when the bulbs were put side by side nearly all the staffers were able to tell that the new CFL was brighter. The Utilitech, $1.65, trades some brightness for a slightly faster warm up time. The Feit Electric Ecobulb Plus, $2.35, took a few seconds longer to warm up but is slightly brighter. The EcoSmart, at $1.50, is the least expensive but dimmest of these CFLs. We'll continue testing the 100-watt equivalent CFLs to see if lumen output drops more.
Halogens offer some advantages. Beside brightness, halogen bulbs are dimmable and warm up instantly. Halogens’ color rendering index is also higher. CRI measures how accurately the bulb displays colors. The Philips Energy Saver T60 Halogena, $5.50, was the brightest bulb we tested. It provides a soft white light. The lower-scoring Sylvania Soft White Halogen, $2.25, was also brighter than the CFLs, but not bright enough given how much energy it uses, which is why it didn't make our recommended list. Though both halogens meet the new energy-efficiency standard and use less energy than the incandescents they replace, they still use significantly more than CFLs and don't last nearly as long. This short lifespan, similar to a standard incandescent bulb, is one reason why halogens don't meet Energy Star standards and don't carry the Energy Star logo.
LEDs lagging. Many 60-watt replacement LEDs were impressive in recent tests and prices are dropping fast, but LEDs aren't yet bright enough to replace a 100-watt incandescent. Manufacturers are still working on fitting all the chips and circuitry needed to produce enough lumens into a standard-size bulb, and on dispersing the heat these components generate. They hope to have 100-watt replacements on store shelves by Spring or later. Consumer Reports is currently testing a 75-watt LED replacement bulb.
Remember all 100-watt equivalent CFLs we tested provide substantially more light than the 60-watt CFL replacements we tested earlier. So if you're just looking for more light than a 60-watt bulb, any of the recommended 100-watt replacement CFLs should be fine. They all provide a warm, yellow light but are slightly larger than the incandescents they replace. The halogens' light is slightly whiter. Use the color temperature of the light, measured in Kelvins and on the bulb's label, to gauge how yellow, white or blue the light will be. Temperatures of 2,700 to 3,000 come closest to incandescent light. The higher the Kelvin, the whiter or bluer the light will be. While the coolest light provides more contrast, its bluer tones can be unflattering indoors.