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.

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designed to kick-start a new era of greener, longer-lasting, more cost-efficient light bulbs — and this meant kicking outdated, inefficient bulbs to the curb.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 100- and 75-watt incandescents obsolete, and on January 1, 2014, their 60- and 40-watt cousins will meet the same fate.

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 134 years, 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.

LEDs

Average cost: $10 – $25

Average wattage: 4 – 22 watts

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 12-watt 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 you're using it for 3 hours a day at an energy rate of 11 cents per kilowatt hour (kWh). Under those same parameters, a 60-watt incandescent bulb that puts out 880 lumens will cost about seven and a half bucks per year.

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 12-watt LED would pay for itself in 2.5 years, then keep on saving you money for years to come.

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 always go wrong. Fortunately, more and more LED bulbs come with multiyear warranties for cases of mechanical failure. One manufacturer, Cree, even goes as far as to offer a 10-year warranty for its highly rated TW Series 40- and 60-watt replacement bulbs, both of which cost less 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

Average cost: $5 – $20

Average wattage: 9 – 52 watts

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 in order 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 argument against 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.)

Ref: CNET

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