Buy the bulb with the highest light output using the lowest number of watts.
The incandescent lightbulb, invented by Edison and warmly illuminating our homes for nearly a century, will officially burn out in a few years. In 2007 Congress decreed that all lightbulbs sold in the U.S. must be 30 percent more efficient by 2014 and 70 percent more efficient by 2020 compared to the standard incandescent bulbs on store shelves today. Compact fluorescent (CFL) bulbs already meet those criteria, but recent sales figures released by the government’s Energy Star program show that sales of CFLs dropped in 2008, for the first time since 2002. Possibly this is the recession at work, or concern about the mercury content in CFLs has people stockpiling their beloved incandescents. But some bulb shoppers may be wondering if they should skip over CFLs and invest in the pricier, emerging technology of LEDs, or light-emitting diodes. Which is the better choice?
This: Compact Fluorescent Light Bulb
Pros: CFLs have become much more affordable lately, costing on average about $3 per bulb. That’s still more than a 50-cent incandescent, but what you pay for up front, you save on your utility bills and in the cost of replacing all those 50-centers: CFLs are 75 percent more efficient and last up to 10 times longer. According to Energy Star’s CFL savings calculator (which you can download for free and use to see how much you’ll save), replacing a 60-watt bulb with a 15-watt CFL can pay for itself in about four months.
Cons: Mercury is probably at the top of the list for anyone who has concerns about CFLs. It’s true that the bulbs contain an average of 4 milligrams (mg) of mercury, according to Energy Star, which you can be exposed to if the bulb breaks. When they (eventually) burn out, CFLs have to be disposed of properly to keep that mercury out of the environment. And there have also been reports of workers in China suffering from mercury poisoning after being exposed to it in fluorescent bulb–producing factories.
That: LED Light Bulb
Pros: Even more efficient than CFLs, LEDs use half the electricity of those bulbs and eight times less than incandescents, and they cost a mere $2 to run for an entire year. They’re also free of mercury, and many companies make them in unbreakable casings.
Cons: Cost and availability are LEDs’ main detractors. Currently, most bulbs designed to replace incandescents in overhead and reading lights run upwards of $50, and can be purchased online only, making them impractical for many people. They also don’t put out as much light as CFLs or incandescents, and produce a bright white light, as opposed to the warm yellow most of us prefer. (CFLs have also been criticized as being too dim or too cold, but careful shopping can get you around those problems).
This or That?
This. Go with CFLs. If you want to try out the more expensive LEDs, go for it. They’re greener overall than CFLs, and you can find some less-pricey LED lights appropriate for ambient lighting or decorative lamps. However, you’ll have better quality light and nearly as good energy savings with CFLs. Their manufacturers have started addressing people’s concerns about mercury, as well. Philips “Alto” line of low-mercury CFLs contain only 1.7 mg of mercury, and the EcoSmart and n:Vision lines of bulbs sold through Home Depot contain 2.3 to 3.5 mg, respectively. Keep in mind that including the mercury content inside them—and assuming it’s not disposed of properly—a CFL adds half as much mercury to the environment over its life span as an incandescent bulb. That’s because it requires less energy to operate. Coal-fired power plants, which generate half of our nation’s energy, are the primary sources of mercury in the environment, and can pump out 13.5 mg of mercury to power an incandescent bulb for its life span.
Buying CFLs can be confusing, so here are three things to look for when you need illumination:
• Lumen output. Don’t rely on watts as a measure of brightness. Lumen output is a much more accurate measure of the light a bulb will produce, and it can vary among bulbs with the same wattage. A 14-watt CFL, for instance, can emit as little as 700 or as much as 900 lumens. For ambient lighting, you want between 400 and 500 lumens; overhead fixtures need between 890 and 1,380; and reading lamps will need the most, between 1,750 and 2,780. Buy the highest lumen output at the lowest wattage to get the most energy savings.
• Kelvins. If you’ve ever purchased a CFL only to install it and find yourself bathed in public restroom–style harsh blue light, you’re not alone. Before you buy, look on the label for a bulb’s Kelvins (k), which is a measure of light temperature. The higher the Kelvin temperature, the colder the light (yeah, it’s a bit counterintuitive). Warm light, similar to an incandescent bulb’s, runs 2,700 k, while cooler light is 3,500 k. Bulbs with 5,000 k or more are most similar to daylight; those are best for outdoor flood lamps or garage workspaces.
• Shape and size. As CFLs increase in wattage and lumen output, they tend to also increase in size. Keep your home’s ceiling fixtures in mind as you shop so you ensure the bulb will fit when you get it home. You can get bulbs designed to look like incandescents; they have a globe or candle-shaped casing over the increasingly familiar spiral coils. The casing can decrease brightness, so buy those bulbs at slightly higher lumen outputs than you would an equivalent spiral-shaped CFL.
• Proper disposal. The best way to prevent the mercury in a CFL from contaminating the environment is to dispose of it properly. Visit http://www.lamprecycle.org
to find a location near you. If you break a bulb in your home, follow Energy Star’s guide for cleaning it up.