Light bulb buying guide

With strict new standards, the landscape of lighting is rapidly changing. Here's everything you'll need to know to keep up.

Colin West McDonald/CNET

When Congress passed the Energy Independence and Security Act of 2007 (EISA), the incandescent bulb's days officially became numbered. The law mandated strict new energy standards for lighting designed to kick-start a new era of greener, longer-lasting, more cost-efficient light bulbs -- and this meant kicking outdated, inefficient bulbs to the curb.

The rising standards have already rendered 100W and 75W incandescents obsolete, and on January 1, 2014, their 60W and 40W cousins met the same fate. Congressional budget waffling seemed to put the new standards on hold, but it was largely too late -- the industry had already moved on, and wasn't interested in reversing course.

Like it or not, the arrival of this new era means that replacing your lights will never be quite the same. With all of the new options out there (not to mention the disappearance of some important old ones), finding the perfect bulb can seem pretty daunting. New lights that promise to last 20 years and save you hundreds of dollars might sound good in theory, but how do you know which one is the right one for you? How do you know the bulb you're buying is going to be bright enough? And what if you're just not ready to say goodbye to your incandescents?

Well, fear not, because we've got you covered with a handy guide that's chock-full of all the information you'll need to make sure that your next light bulb is the right bulb.


What kinds of bulbs are available?

We've all gotten to know incandescents quite well over the past 135 years or so, but times are changing. These days, you've got some new lighting categories to familiarize yourself with, and doing so is the first, most obvious step toward buying the right bulb.

Some LEDs stand out for their space-age looks. Tyler Lizenby/CNET


Average cost: $5 to $25
Average wattage: 4W to 22W
Average life expectancy: 20,000 hours

Light-emitting diodes, or LEDs, are the new rock stars of the bulb world. When an LED is switched on, electrons and electron holes come together (don't worry, I'm not completely sure I fully understand what a " hole" is in this context, either). The result of this process is a release of energy in the form of photons, or light.

A typical LED uses a fraction of the wattage required to power a bright incandescent bulb, and this makes LEDs dramatically more cost-effective over the long run. A 12W LED that puts out 800 lumens of light (lumens are units of brightness for a light source -- more on that in just a bit) will add about a buck and a half per year to your power bill if used for 3 hours a day at an energy rate of 11 cents per kilowatt hour (kWh). Under those same parameters, a 60W incandescent bulb that puts out 880 lumens will cost about $7.50 per year. Multiply that by the total number of bulbs in your home, and you're potentially looking at some pretty significant long-term savings.

LEDs are also rated to last for tens of thousands of hours, which can translate to decades of use. Compare that with the year or so you typically get out of an incandescent, and you can begin to see why so many people find these bulbs appealing. At a price of about $15, that 12W LED would pay for itself in 2.5 years, then keep on saving you money for years to come.

This Insteon LED promises to last for a whopping 52,000 hours. Colin West McDonald/CNET

Decades? Really?

Yes, really -- at least, according to Energy Star and the Illuminating Engineering Society (IES), the independent organization that created the testing procedures manufacturers use to rate LED lights. Most LED bulbs have only been commercially available for a few years now, not nearly long enough to see direct proof of their longevity claims. Fortunately, there's enough transparency with LED testing that we're able to dig a little deeper into what these claims are actually saying.

First, it's important to understand that LED lights don't "burn out," the way that incandescents do. Instead, they undergo "lumen depreciation," gradually growing dimmer and dimmer over time. The test that the IES uses to determine a bulb's longevity is known as the LM80, and it calculates how long it will take for an LED to fade noticeably. Engineers run the bulb for nine months in order to get an accurate read of the light's rate of decay, and using those figures, they can calculate the point at which the light will have faded to 70 percent of its original brightness. This point, known as "L70," is the current standard in LED longevity. If an LED says it'll last 25,000 hours, it's really saying that it will take the bulb 25,000 hours to fade down to 70 percent brightness.

This isn't to say that LEDs don't fail. They definitely do. As with any device relying on tiny, delicate electrical components, things can go wrong. Fortunately, more and more LED bulbs come with multiyear warranties for cases of mechanical failure. Some manufacturers, like GE and Cree, offer bulbs with 10-year warranties, none of which cost more than $20. Consumers with a healthy dose of skepticism regarding LED longevity claims should look for bulbs like these, by manufacturers willing to put their money where their mouth is.

CFLs like this one are great energy-savers. Ry Crist/CNET


Average cost: $2 to $20
Average wattage: 9W to 52W
Average life expectancy: 10,000 hours

Before LEDs exploded into the lighting scene, compact fluorescent lights (CFLs to you and me) were seen by many as the heir apparent to incandescent lighting. Despite the fact that CFLs use between one-fifth and one-third the energy of incandescents, and typically save one to five times their purchase price over the course of their lifetime, many people weren't thrilled at the idea of switching over. Some find the whitish light output of CFL bulbs less aesthetically pleasing than the warm, yellow tone of most incandescents. Others are quick to point out that CFL bulbs that regularly get powered on and off for short periods of time tend to see a significant decrease in life expectancy. There's also the common complaint that most CFLs aren't dimmable, and that they often take a second or two after being switched on to fully light up.

The good news here is that CFL technology has improved a lot since EISA was signed into law in 2007. Today, you'll find a greater variety of color options, including bulbs rated at the low, yellow end of the Kelvin scale, and you'll have an easier time finding dimmable CFLs, too. There are even "instant-on" CFL bulbs designed to eliminate that annoying delay between flipping the switch and seeing the light.

The bad news is that in spite of these improvements, CFLs remain somewhat flawed. They're still prone to decreased life expectancy when you use them in short increments, so ideally you'll want to save them for lighting that you're going to keep on for longer periods of time. Additionally, most CFLs aren't intended for outdoor use, and some will fail to turn on in colder temperatures -- although you can find cold-cathode CFL bulbs rated for temperatures as low as -10 degrees Fahrenheit.


Aren't CFL bulbs dangerous?

Like all fluorescents, CFLs contain trace amounts of mercury -- typically 3 to 5 milligrams (mg), although some contain less. This creates the potential for pollution when CFL bulbs are improperly disposed of, something that led to a unique environmental argumentagainst the phasing out of incandescents (although, to be fair, this was before LEDs were seen as such a viable option).

The amount of mercury vapor in a standard CFL bulb is about one-hundredth of what you'd find in an old-fashioned thermometer. Even in such a small amount, mercury merits a degree of caution, as direct exposure can cause damage to the brain, lungs, and kidneys. That said, if a CFL shatters on your kitchen floor, you don't need to panic or evacuate your home. Just be sure to open a window and let the room air out for 10 minutes, then carefully transfer the glass and dust into a sealable container (and don't use a vacuum cleaner -- you don't want to kick those chemicals up into the air). If you can take the broken bulb to a recycling center for proper disposal, great. (For more info on CFLs and mercury, click here.)

Your days are numbered, pal (or are they?) Ry Crist/CNET


Average cost: $1 to $10
Average wattage: 40W to 150W
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 non-traditional 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.

This halogen bulb glows with a warm, incandescent-like light. Ry Crist/CNET


Average cost: $2 to $15
Average wattage: 29W to 72W
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.

Ry Crist/CNET

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.

With well over 800 lumens, this 11W Philips LED bulb would make a good replacement for a 60W incandescent's brightness. Ry Crist/CNET


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 40W bulb: look for at least 450 lumens
Replacing a 60W bulb: look for at least 800 lumens
Replacing a 75W bulb: look for at least 1,100 lumens
Replacing a 100W bulb: look for at least 1,600 lumens

A yellow, low-color-temperature bulb compared with one with a bluish, high color temperature. Ry Crist/CNET

Color temperature

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 really hot, 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.

Sylvania often color codes its packaging. Blue indicates a hot, bluish color temperature, while the lighter shade indicates a white, more neutral light. Ry Crist/CNET

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 score 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 score of lights like those is abysmal.


Now here's the rub: the CRI is highly imperfect and not always useful (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.

In general, 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. The GE Reveal BR30 floodlight LED won our Editors' Choice distinction for its emphasis on color rendering. There's even a $5 LED from Ikea that scores in the upper 80s. If accurate color rendering is important to you, look 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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