In The Dark About Picking A Light Bulb? This FAQ Can Help

Feb 18, 2014
Originally published on May 7, 2014 8:23 pm

Buying a light bulb used to be a no-brainer. Now it's a brain teaser; the transition to more energy-efficient lighting means choosing from a dazzling array of products.

We've long identified bulbs by their wattage, but that is actually a measure of electricity, not the brightness of a bulb. The amount of light a bulb generates is measured in lumens.

An incandescent 60-watt bulb, for example, gives off 800 lumens of light. And LED bulbs, which are more energy efficient than their incandescent counterparts, can deliver the same amount of light using as little as 10 watts.

The Environmental Protection Agency says that if every household replaced just one incandescent bulb with an "Energy Star"-rated LED or CFL (compact fluorescent), Americans would save close to $700 million per year in energy costs.

But with so many types of bulbs with different price points and life spans now on the market, many consumers are confused.

When we asked for your questions about light bulbs, we got an earful. So we called in Noah Horowitz, director of the Natural Resources Defense Council's Center for Energy Efficiency, to answer your most frequently asked questions.

(We should note that Natural Resources Defense Council, a nonprofit environmental organization, is a strong backer of energy-efficient lighting. It receives a small percentage of funding from government grants, including one from the EPA Energy Star program to accelerate the adoption of energy-efficient equipment.)

For even more information about light bulbs — the different types available, how long they last and what they cost over the life of the bulb — check out our guide to changing light bulbs.

Why do some CFLs die so quickly? The whole seven-year life thing seems random. I have some bulbs that last years but others that die within a year.

As not all CFLs are created equal, only buy those that have the Energy Star logo on them. Those bulbs are not only efficient but also meet the Environmental Protection Agency's rigorous performance requirements and must pass various tests including longevity. Switching your CFL on and off frequently may shorten its life. Additionally, CFLs may not turn on or reach their full brightness in really cold temperatures.

Everyone I've talked to says they just throw dead CFLs in the trash. Isn't this a problem for landfills? Are we going to start hearing about dangerous mercury levels in the ground and water in a few years?

CFLs have very low levels of mercury in them, now as low as 2 mg per bulb. Consumers should take advantage of free CFL recycling programs that are offered by leading retailers such as Home Depot and Lowe's. You should also be aware that while incandescent bulbs do not contain mercury, they cause a lot more mercury to be emitted into the environment from coal-burning power plants, since they use four times more energy than a CFL to produce the same amount of light.

I have at least three lamps that use a three-way bulb (50/100/150), and I like having the option in terms of brightness. Is there a CFL or LED version of the three-way bulb?

If you want to have different levels of light and use an energy-saving bulb, you have two great choices. If you have a three-way socket, you can buy a three-way CFL which will offer low, medium and high light output, just like your old incandescent bulb did. If your fixture is dimmable, almost all LEDs are dimmable and you can enjoy even more flexibility.

Are there CFLs or LEDs for candelabra bulbs? What about globe-shaped bulbs for my bathroom vanity?

The great news is there is an energy-efficient CFL or LED for just about every socket. These include candelabra or flame-shaped bulbs, as well as the round globe-shaped bulbs that are often used in the bathroom vanity over the sink. Candelabra and globe CFLs have been around for years, and LED models are coming on line now, too.

I have some sockets that take nothing higher than a 60-watt bulb. If I use an LED or CFL, can I use a brighter bulb? For instance, a 13-watt CFL is equivalent to a 60-watt incandescent. Is it OK to use a 23-watt CFL instead? That would give me the equivalent of a 100-watt incandescent.

Fixtures have a safety rating and one should not put in bulbs that exceed the labeled rating (such as "do not exceed 60 watts"). As long as you don't put a bulb that uses more than 60 watts in that socket you will be fine.

The good news is the energy-saving bulbs that replace a 60-watt incandescent will only use 10 to 15 watts, depending on the actual bulb you buy, and give off the same amount of light. If you want even more light, you can bump up to a 23-watt CFL that will give off as much light as the old 100-watt bulb did, while still staying below the 60-watt power cutoff. You should not, however, install a 100-watt bulb, as that could cause a fire hazard.

Are there some places in the home where you would recommend CFLs over LEDs or vice versa, such as in outdoor fixtures that are exposed to temperature extremes? Or in indoor lamps?

CFLs do not work well in cold climates and may not even start, so are not a good choice for the porch light or other outdoor sockets in cold climates. We recommend consumers select LEDs for use in recessed cans and downlights as they are better at serving as directional lights, and for sockets that are connected to a dimmer.

For those bulbs that are not used very often and are not switched on and off frequently, CFLs are probably your best bet. Conversely, put LEDs in hard-to-reach sockets, as they last up to 25 years (at three-hours-per-day usage), and you'll avoid the hassle of having to change the bulb for a really long time.

Are there dangers to putting LEDs into enclosed fixtures or in the recessed cans in my ceiling? Could they overheat?

The electronics inside the LED may fail if they are subjected to very high temperatures. LED reflector lamps are specially designed to withstand the high temperature environments found inside recessed cans, the downlights or circles in your ceiling. If you put an LED into an enclosed fixture, it may shorten its lifetime. Look for those that are labeled as being suitable for use in enclosed fixtures.

I don't understand color temperature. "Daylight" made walking down my hallway to the bathroom feel like walking into a jail. How do we determine, before buying, whether the light from the bulb is "good" — i.e., not too harsh, bright enough and sufficiently diffuse?

CFLs and LEDs come in different "flavors" of light. If you want to replicate the old yellowish white light that your incandescent gave off, look for bulbs that are marketed as "soft white" or "warm white." Conversely, if you prefer the light to have more of a bluish-white color, then select a lamp that is marketed as "daylight."

Before you go out and switch out all the bulbs in your home, we suggest you try one of each and see which one you like. While CFLs, when first introduced 20-plus years ago, did not give off pleasing light, today's CFLs are much improved and in many cases you'd be hard pressed to notice the differences from your old incandescent. Regarding LEDs, we find people love everything about them including the light quality, with the exception of the purchase price — which fortunately is dropping every day.

Many LEDs just don't dim smoothly and simply turn off before they reach a desired low level. Why? Will dimming improve?

Dimmable LEDs will work with most, but not all, installed dimmers. In a few cases, you might need to replace your dimmer and install one that is designed specifically for LEDs and CFLs, which use four times less power than the old incandescents did. In order to obtain the Energy Star label, dimmable lamps must dim down to 20 percent of full light output without a noticeable hum or flicker. As LEDs are still relatively new products, we expect future dimmable LEDs to perform even better.

I like LEDs, but I feel like I'm being gouged. Why are LEDs still so expensive, especially the brighter ones? When will the price come down?

The price of LEDs is dropping rapidly. The LED bulb that replaces the old 60-watt incandescent that used to cost $40 just a few years ago is now down to $10 or so today. [Note: NPR recently purchased 60-watt equivalent LEDs at Home Depot for less than $5. Noah Horowitz believes this price reflects an instant rebate from local utilities.] Also keep in mind that the $10 or $20 LED you just bought will save you $100 or more over the life of the bulb in the form of lower electricity costs.

Also, the individual LEDs are getting more efficient, which means manufacturers can use fewer LEDs in the bulb to deliver the same amount of light and they will need less aluminum as a heat sink, since there will be less heat to manage. All of this translates to lower costs. The LED bulbs that give off the same amount of light as old 75- and 100-watt incandescents cost more, because they require more LEDs and related materials. Their price, too, will come down with the efficiency gains and the economies of scale that come from higher production levels.

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From NPR News, this is ALL THINGS CONSIDERED. I'm Audie Cornish.


And I'm Robert Siegel. Now, a household decision that used to be a no-brainer and has turned into brain teaser - buying light bulbs. This is Gino Hefner, paying a sales call on Phyllis Cole of Potomac, Md.


GINO HEFNER: Hello. How are you? I'm Gino.

COLE: Hi, Gino.

HEFNER: Gino's business is a sign of the times. It's called the LED Diet. He comes to homes with a van load full of LED light bulbs - the latest in energy-efficient lighting - to help out customers like Phyllis, who are absolutely stumped by the current moment in light bulb history.

COLE: We don't know what to do. We went to Home Depot and got totally confused. It wasn't their fault.

HEFNER: Did you purchase anything? Did you try anything?



COLE: I left.


SIEGEL: Gino's spiel is not just a sales pitch. It's a tutorial in LED bulbs, bulbs that use light-emitting diodes.

HEFNER: It's a very confusing process now. There's new terminology, obviously, that leads people astray. You start hearing the word lumens instead of wattage. It does become very intimidating.

SIEGEL: For generations, we've been talking about a light bulb's wattage: 60, 75, a hundred watts. Wattage is actually a measure of electricity. The light that a bulb generates is measured in lumens. That's a word that you now see on packaging. An incandescent 60 watt bulb gives off 800 lumens of light. An LED bulb can deliver the same amount of light with as little as 10 watts.

HEFNER: So if you had one, two, three, four, five, that's 325 watts, we'll get you down to 50 watts.

COLE: Really?

HEFNER: So you see that immediate savings just right there.

SIEGEL: Savings on her monthly electric bill. The prospect of big national savings is what's driving the case for more energy-efficient lighting. For a couple of decades now, compact fluorescents - or CFLs - have been on the market, with mixed results. Today, most of us still light our homes with incandescent light bulbs. The Environmental Protection Agency estimates that they're in about 70 percent of the 4 billion sockets in American homes.

The EPA says that if every household replaced just one incandescent bulb with an Energy Star-rated CFL or LED, we'd save close to $700 million a year in energy costs. Of course, LEDs are a lot more expensive than incandescent bulbs, or even CFLs. Those 10 watt, 800 lumen bulbs that Gino Hefner put in Phyllis Cole's recessed ceiling fixtures cost $40 a piece. But they're built to last a lot longer.

HEFNER: The average LED that we're using is like a 25,000-hour rating. So if you're leaving the average light on, let's say, for three hours a day, you're looking at 22 years.

COLE: Are you serious?


SIEGEL: How serious are those numbers? You may be thinking right now of a compact fluorescent you bought on the promise of nine years of life, one that bit the dust after just one year. Well, as I learned at the Lighting Research Center in Troy, N.Y. - it's part of Rensselaer Polytechnic Institute - the estimated life of a bulb isn't a minimum, it's a mean. [POST-BROADCAST CORRECTION: It's actually a median, not a mean.] They simulate usage of a test sample of bulbs and when half the sample is dead, that is the life of the bulb. Here's how Professor Nadarajah Narendran puts it.

NADARAJAH NARENDRAN: There's always a range, which falls on a bell curve. And if you are the unlucky one, you'll get the light bulb that's going to fail the fastest. If you're the lucky one, you'll go beyond what was promised.

SIEGEL: The research center studies all aspects of electrical lighting: how long do bulbs last, how much energy do they use, how does their light change over time? And there's a range of quality by brand - a range that Professor Narendran figures is going to broaden.

NARENDRAN: Once the technology has matured, we are going to get products from all over the world. Some of the manufacturers will be very conscious about the quality. The other ones, to give you a light bulb at a very low cost, may not pay attention to the quality. This is why they say, you get what you pay for.

SIEGEL: Even though LEDs have barely penetrated the home lighting market, people who follow that market say this is the lighting of the future. Compact fluorescents are now seen as a transitional technology, a technology that has improved but one that never overcame a bad reputation, especially for color.

The Lighting Research Center's director, Mark Rea, is confident that LEDs can offer better color than CFLs. In fact, he says LEDs can do better with color than incandescents, which have provided the light that all of us are accustomed to.

MARK REA: So what we're going to try to do - to show you here today is different types of light sources people have actually begun to build, based on our research. And we want to get your impression of whether you see any difference at all. All right? So let me turn the room lights off.

SIEGEL: Dr. Rea showed me two identical displays of groceries on either side of a black divider: an orange, a lemon, a purple onion, a blue box of Pop Tarts, assorted berries, a bottle of mineral water, an eggplant. It's all set out on checkered tablecloths; two side-by-side, modern-day still life tableaux.

This is a kitchen that Cezanne, if he'd been alive today...


SIEGEL: ...would have painted this kitchen scene.

Mark Rea showed me various comparisons - first, incandescent light on the left side, and the much more efficient LED on the right. Both looked pretty good, and not all that different.

I see the Pop Tart box as being a somehow a bit brighter on the right side than it is on the left side. And maybe the bottle of sparkling water, too. Maybe the blues are a little bit bluer on the right side.

REA: You do have a keen eye.

SIEGEL: Thank you for saying that.

REA: These are very small differences, but you're picking up those differences. Now, here's another alternative.

SIEGEL: Rea changed the lighting scheme to show me what LED technology can do with color. Now, we had two different LED bulbs. The one that I just saw was on the left, and a kind of a souped-up LED was on the right. And this time, the two sides looked very different. The left side looked yellowish and pale, while the colors on the right side looked vivid. The purple onion was a rich, almost liquid purple. The blackberries glistened. Mark Rea told me this setting went over very well with supermarket produce managers they brought in.

REA: They want the fruits and vegetables to really sort of stand out, and people are to be impressed. So, the one on the right is kind of pushing the envelope to say: We can get a little more saturation or vividness or colorfulness - particularly in the purples and the blues - than you can with your traditional source.

SIEGEL: There are infinite color options with LEDs, Rea says. The challenge is educating consumers about the new choices, and getting people to embrace them.

REA: The industry is struggling to assure customers that the new technology is really not going to just - not only not disappoint, but that you have these better options that are available, too. That's the challenge. How do you communicate this effectively?

SIEGEL: The fact that we are three decades into what was supposed to be a transition away from incandescent bulb, is one measure of what Michael Siminovitch, of the University of California-Davis, calls a failed transformation.

MICHAEL SIMINOVITCH: We should be done by now. In other words, true market transformation should have happened. If you look at the amount of resources that we've put into this, massive amounts of money have gone into it convincing the consumer that compact fluorescent was a great technology and it would satisfy them; and we would have total market transformation. Sadly, we're not there.

SIEGEL: Siminovitch is director of the California Lighting Technology Center at UC-Davis. He's optimistic about LEDs and especially the advances that are being made with color and quality. And he warns that if the light bulb of the future doesn't appeal to consumer tastes - not just energy needs - the conversion to LEDs could fail just as the shift to CFLs did.

SIMINOVITCH: It's a very complex equation - our demand for satisfaction and for preferences. And I think on one hand, you can make a light source be acceptable; in other words, you won't trip or fall, you can find your way in the dark. But there's a very big difference between something that's acceptable, and something that's preferable. I think it's an important lesson that the efficiency community needs to learn.

SIEGEL: (Laughter) It's ironic that what you're saying is, a transition that is all about achieving energy efficiency should be a little less preoccupied with energy efficiency.

SIMINOVITCH: Absolutely. You're not going to get there with energy efficiency and cost. The true Trojan horse for this is appealing to consumers' quest for color and quality.

SIEGEL: So when we buy a light bulb, we determine how our food looks on the table, how we look in the mirror, how often we'll have to change it and the bottom line, how much energy we use. I am still confused by that set of choices. And judging from a call-out we made on Facebook, so are many of you.

Well, Noah Horowitz, who's a senior scientist at the Natural Resources Defense Council, has been answering our questions. And he joins us now. Welcome to the program.

NOAH HOROWITZ: Nice to be here.

SIEGEL: And I'll just note that a small part of NRDC's funding comes from government grants, including the EPA's Energy Star Program. Let me put some questions to you. First, are incandescent bulbs banned, and what did the recently passed spending bill do to the light bulb conversion?

HOROWITZ: Let's start at the beginning. Consumers can continue to buy incandescents. The only requirement is that all new bulbs need to use less energy. So they took the old incandescent, changed the guts of it; so there's a new filament and a halogen gas inside that makes incandescents use 28 percent less energy than they used to.

SIEGEL: As for the most recent bill, it took away funding for enforcement of conversion?

HOROWITZ: Yes. The standards are still in place; merely, the Department of Energy isn't allowed to spend money to enforce the standards. The good news is all the big lighting companies - like G.E., Philips and Osram - have completely switched over and are making these energy-saving bulbs.

SIEGEL: If I plan to buy some combination of CFLs and LEDs, let's say, would you recommend each kind of bulb for certain, specific uses?

HOROWITZ: Yeah. The great news is there's an energy-saving bulb for every socket. CFLs continue to be your lowest-cost energy-saving bulb. Some of the issues remaining with CFLs is they don't dim, and it takes a little while for the light to come on. LEDs have solved that problem, and they're the perfect bulb for most applications. The only concern is LEDs still cost a lot, but their price is coming down really fast.

SIEGEL: For outdoor lighting, which would you recommend?

HOROWITZ: CFLs will not turn on if you live in a very cold climate and have the lamp outside. So the porch light in New Hampshire in the middle of winter won't turn on, or won't reach full brightness. So in that case, you definitely want the LED. You can also put an energy-saving incandescent there as well. That will work just fine. It will just use a lot more power.

SIEGEL: Here's a question we've heard from several people. I have some sockets on lamps where it says don't use anything more than a 60-watt bulb. But if I use an LED or a CFL, which uses far fewer watts than that, can I have one, say a 23-watt CFL that generates more light than I was getting from the 60-watt incandescent?

HOROWITZ: Yes. Many fixtures have a power rating. It's a safety rating. Do not put more than a 60-watt or 100-watt bulb into this socket. As long as you stay below that, you're fine from a safety point of view. If you want to bump up to a brighter light bulb, you can pick, let's say, a 23-watt CLF and that will give off as much light as the old 100-watt bulb did.

SIEGEL: One of our Facebook visitors wrote this: I don't understand color temperature. Daylight, which was a description of a bulb, made walking down my hallway to the bathroom feel like walking into a jail. How do we determine, before buying, whether the light from the bulb is good - not too harsh, bright enough and sufficiently diffuse?

HOROWITZ: This is a complicated one. Lamp companies market their bulbs as either warm, which means it has a yellowish-white light; and that's what people are used to. There are other bulbs that are marketed as cool or daylight, and those have a bluish-white look. Some people hate that, and some people love it; it's a very personal choice here. What we recommend is, people choose one of each and if in doubt, pick the one that's marketed as warm or soft white light.

SIEGEL: Noah Horowitz, thanks for talking with us about light bulbs.

HOROWITZ: My pleasure.

SIEGEL: Noah Horowitz is a senior scientist at the Natural Resources Defense Council. There are more of his answers to your questions online, at Transcript provided by NPR, Copyright NPR.