Light bulb buying guide (continued…)
Average cost: $2 – $10
Average wattage: 40 – 150 watts
Average life expectancy: 1,000 hours
When I tell you to picture a light bulb, chances are good that you're envisioning an incandescent. This is the classic bulb of Thomas Edison: a tungsten filament trapped within a glass enclosure. Electricity heats the filament to a point where it glows, and voila, you have light.
Aren't incandescents banned?
As a matter of fact, they aren't. EISA doesn't actually ban anything, at least not directly. What EISA does do is raise efficiency standards — specifically, the minimum acceptable ratio of lumens (light) per watt (electricity). Incandescents aren't banned; they simply have to become more efficient. Also, keep in mind that appliance lights and other specialty classes of incandescents are exempt from the new standards, so they aren't going anywhere.
It's true that traditional incandescents unable to keep up with the times will be phased out. However, the door is still wide open for nontraditional incandescents to take their place, and we're already seeing some manufacturers rise to the challenge, with high-efficiency incandescent bulbs that manage to meet the new standards. Key among these high-efficiency bulbs is yet another lighting option you'll want to consider:
Average cost: $3 – $15
Average wattage: 29 – 72 watts
Average life expectancy: 1,000 hours
Halogens are just incandescent bulbs with a bit of halogen gas trapped inside with the filament. This gas helps "recycle" the burned-up tungsten gas back onto the filament, making for a slightly more efficient light. Unlike the mercury in CFLs, this gas isn't anything that could be classified as hazardous waste.
Due to their relative similarity to classic incandescents — both in light quality and in cost — halogens can work as a good compromise bulb for consumers who need to replace their incandescents, but who also aren't ready to commit to CFLs or LEDs quite yet.
What information should I be looking for?
You want to be sure that you'll enjoy living with whatever light bulb you purchase, especially if you're choosing a long-lasting bulb that you'll live with for years. Fortunately, the Federal Trade Commission now requires light bulb manufacturers to put a "Lighting Facts" label onto their products' packaging, not unlike the Nutrition Facts label that you'll find on packaged food.
These Lighting Facts include everything from the estimated yearly cost of using the bulb to more obscure figures, like lumens and color temperature. If you want to shop smart, it will help to understand as much of that terminology as you can.
If you're buying a bulb these days, you'll be left in the dark if you don't know what a lumen is. The actual definition gets a bit complicated, involving things like steradians and candela, but don't worry, because all that you really need to know is that lumens are units of brightness. The more lumens a bulb boasts, the brighter it will be. So, how does this information help you?
Let me give you an example. If you look at CFL or LED bulbs, you'll see that most all of them are marketed as "replacements" for incandescent bulbs of specific wattages. You'll probably see the word "equivalent" used, too, as in "60-watt equivalent." This can be frustratingly misleading, with "equivalent" often meaning something closer to "equivalent…ish." Relying on these wattage equivalencies can lead you to buy a bulb that ends up being far too dim or too bright for your needs, and this is where understanding lumens really comes in handy. With lumens listed on each and every bulb, you'll always have a concrete comparison of how bright any two bulbs actually are. The bigger the number, the brighter the bulb — easy enough, right?
How many lumens do I need?
Over the last century, we've been trained to think about light purely in terms of wattages, so it isn't surprising that most people really have no idea of how many lumens they actually need in a bulb. Until you form an idea of how bright is bright enough for your tastes, stick with these figures:
Replacing a 40-watt bulb: look for at least 450 lumens
Replacing a 60-watt bulb: look for at least 800 lumens
Replacing a 75-watt bulb: look for at least 1,100 lumens
Replacing a 100-watt bulb: look for at least 1,600 lumens
After lumens, the next concept you'll want to be sure to understand is color temperature. Measured on the Kelvin scale, color temperature isn't really a measure of heat. Instead, it's a measure of the color that a light source produces, ranging from yellow on the low end of the scale to bluish on the high end, with whitish light in the middle. An easy way to keep track of color temperature is to think of a flame: it starts out yellow and orange, but when it gets reallyhot, it turns blue.
Generally speaking, incandescents sit at the bottom of the scale with their yellow light, while CFLs and LEDs have long been thought to tend toward the high, bluish end of the spectrum. This has been a steady complaint about new lighting alternatives, as many people prefer the warm, familiar, low color temperature of incandescents. Manufacturers are listening, though, and in this case they heard consumers loud and clear, with more and more low-color-temperature CFL and LED options hitting the shelves. Don't believe me? Take a look at those two paper lamps in the picture above, because they're both CFL bulbs — from the same manufacturer, no less.
These days, bulb shoppers will find so many color temperature options that some lighting companies have cleverly begun color-coding their packaging: blue for high-color-temperature bulbs, yellow for low-color-temperature ones, and white for bulbs that fall in between. With so many choices available, the notion that the phase-out of incandescents is taking warm, cozy lighting with it is a complete myth at this point.
Color rendering index
Unless you live in a disco, you probably want the colors in your home to look somewhat traditional. This is where the color rendering index, or CRI, comes in. The CRI is a score from 1 to 100 that rates a bulb's ability to accurately illuminate colors. You can think of the CRI as a light bulb's GPA for colors, as it actually averages multiple scores for multiple shades. Manufacturers aren't required to list the bulb's CRI number on the packaging, but many of them choose to do so anyway, so you'll want to know what it means.
To understand CRI a little better, let's imagine a basketball game played outdoors on a sunny day between a team in red jerseys and a team in green jerseys. Daylight is the ideal for making colors look the way they should, so it gets a CRI of 100. Most people watching this game would have no problem telling the teams apart, because red would appear clearly red and green would look green.
Now let's imagine that same basketball game — except now played inside that disco I mentioned. We're indoors, it's a little dim, and we're stuck with multicolored spotlights as the only light source. A purple one shines down on a very confused point guard as he takes a shot. Can you tell if he's on the green team or the red one? I wouldn't be surprised if you couldn't, because the CRI of lights like those is abysmal.
Now here's the rub: the CRI is highly imperfect and not always helpful (the reasons why are mind-numbing, but you can read more here if you're curious/masochistic). The important takeaway is that CRI scores are really only helpful if you're talking about bulbs that sit in the middle of the color temperature spectrum. You'll probably see references to "white" or "natural" light on bulbs like these. In these cases, the CRI score can be a great way to tell a good bulb from a great bulb.
Anything over 80 is probably decent enough for your home, but we're starting to see CRI scores creeping up into the nineties on some very affordable bulbs. If accurate color rendering is important to you, hold out for lights like these. And if you're buying bulbs on the high (blue) or low (yellow) end of the spectrum, take any and all CRI claims with a grain of salt.
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