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IRA FLATOW, host:

You're listening to TALK OF THE NATION: SCIENCE FRIDAY. I'm Ira Flatow. Up next this hour, lighting.

If you're like me, you've been replacing your old light bulbs with those new curly compact fluorescents. You know, they fit right into the same socket as the old ones. Some of them do. You got to buy one that's small enough. And they're finally small enough. The manufacturers claim that they use 75 percent less energy than regular bulbs and last 10 times longer than they do. So why aren't these bulbs in every socket in the country?

Well, there are some drawbacks. Some people, for example, don't like the light, the kind of color that the bulb puts out. They think it's too glaring. Or they think they won't like the bulbs so they won't try it, because, you know, when they hear the word fluorescent, they're thinking back to those flickering, buzzing light of elementary school or those old round ones in your kitchen in the '50s. Remember that fixture on the ceiling? Yeah, I do.

Plus, there is a health consideration in using these bulbs. They actually contain a warning label because the bulbs have mercury in them. Mercury. That sometimes surprises a lot of people. And I - when I dropped the bulb the other day and it broke on the floor and the mercury, I'm sure, was a little cloud some place down there. I was worried about it.

So if you're thinking green, what do you do? Is saving energy enough of a reason to switch to the bulbs, or would you worry about what happens when all these bulbs need to get recycled? Where those all that mercury go in a landfill? What happens to it?

Finally, let's talk about what the next generation of lighting technology should be. How about LEDs? You know? Light Emitting Diodes. Or even beyond that. What new technology is on the drawing boards - stuff being developed now?

Joining me now to talk more about these bulbs and all kinds of bulbs, new lighting technology that we may be seeing soon, is my guest Russell Leslie, professor at Rensselaer Polytech in Troy, New York. He's also the associate director of the Lighting Research Center there.

Thanks for talking with us, professor.

Professor Russell Leslie (Rensselaer Polytechnic Institute; Associate Director, Lighting Research Center): Oh, you're welcome, Ira.

FLATOW: Should we be - worried if we drop one of these bulbs and break them?

Prof. LESLIE: Well, the - you have to put the mercury issue in proper perspective. Any fluorescent lamp requires mercury to operate. The manufacturers have been very good over the last few years at reducing the amount of mercury that's required. However the - that is not a reason not to use compact fluorescent lamps. Let me explain why. Whether you're using an incandescent or a compact fluorescent, you're using electricity. And mercury is most harmful for the environment if it gets up into the air.

Now, with the compact fluorescent, especially with the recycling programs that are beginning to spring up all over the country, you can contain that mercury and just have it recycled. But it will require some power and as a large portion of our national power supply has produced coal. Coal produces a lot of mercury into the air itself.

So if you're comparing it to the incandescent, the incandescent is producing more mercury than would be in the compact fluorescent, even if all of that mercury went up into the air due to the emissions from the coal power plants. So even the U.S. EPA, when they look at the balance, will recommend that you do indeed use fluorescent lighting to replace incandescent lighting for that and for many other reasons.

FLATOW: Why is it taking us so long to switch over?

Prof. LESLIE: Well, you hit on it in your introduction that people have in their mind a whole set of negative impressions about primarily fluorescent light and the early compact fluorescent lamps that were available ranging from, boy, they make me look green, do they go flash, flash, flash before they start up.

The current technology has overcome all of these obstacles, and for most applications, the compact fluorescent light will be virtually indistinguishable from what you're used to with incandescent lighting.

FLATOW: In fact, if you shop carefully, you can buy them in just about any color.

Prof. LESLIE: Yes, they have, the color is also an area of great confusion. People will say, well, I want my light bulbs the same color as the daylight. But daylight changes its color throughout the day and tends to be a lot cooler, meaning whiter or bluer, than the incandescent lamps that are in your home. But you can match very closely the color appearance of your incandescent lamp, if that's what you're trying to do with the compact fluorescent.

What you do is you look for a label, which is called the color temperature, correlated color temperature, and it's measured in Kelvins or K. So on the box, it should say 2700 K if you want it to match closely to incandescent, or 3000 K if you wanted to match halogen incandescent.

Now that's still may seem difficult for some, but there's a short cut and that is to look for the energy star label. And if this is a compact fluorescent lamp with an energy star label, it will meet those qualifications unless it states otherwise on the box.

FLATOW: So it's true, it's true like getting like a fire burning, and out of the fire burns, the bluer and whiter it gets. It's the same thing with the fluorescent bulb, the higher the temperature will be to look bluer or whiter.

Prof. LESLIE: That's right. That does not - in a fluorescent bulb - equate to the actual, physical temperature.

FLATOW: Right.

Prof. LESLIE: But it's the color temperature that you would get if you did heat a black body to that temperature.

FLATOW: Now let's talk about past fluorescent bulbs. Let's even go another generation. I'm a great fan of LEDs because they use so little energy, and, you know, they have their flashlights with them. There are spotlights with them. They don't have the mercury in them. Why aren't we seeing more LEDs on the market?

Prof. LESLIE: Well, cost is one big reason, just as that the reason why compact fluorescents have not taken over the market. In the case of compact fluorescents, it is a (unintelligible) cost issue because they pay for themselves quickly due to their reduced operating costs. LEDs are a lot higher right now in first cost, and it's a very rapidly evolving technology. They -when you say they're more efficient, well, it all depends.

Right now, the commercially available LEDs are about in the efficiency range of compact fluorescent better than incandescent. However, that's in open air, and they will change dramatically if they don't have appropriate thermal management.

So an LED can't just be screwed into a regular socket and replace it. You really need to take into account electronics and then convene the heat in a way, which may mean in the future we're going to have fixtures that are specifically designed to be used with LEDs. And the LEDs become an integral part of the fixture.

FLATOW: And - I was the first on my block to get fluorescents (unintelligible). I have a lot of experience with them. And I have noticed that over the years, you cannot just take a compact fluorescent and put it in an overhead can. You know these, the ceiling lights, because it seems to brown out in that one also in a confined area.

Prof. LESLIE: Compact fluorescents are also dropped(ph) performance, as it gets very hot. And then have the impact on its life and light output. If you're putting it in an overhead can, especially if it's an overhead can that is surrounded by insulation - these are the ones that would be in your uppermost floor. And they're called IC airtight fixtures.

That is not the best application for a compact fluorescent lamp. It's a bad application because of the heat that generates. And also compact fluorescent lamps emit their light in all directions. When you're in a can, you want light - you want a light bulb that can focus its light, so that it leaves the can, gets out into the space where you can use it.

So in those cases, sometimes, let's say, a halogen or a halogen eye or incandescent reflector lamp, you might be familiar with it as a spot lamp.

FLATOW: Right.

Prof. LESLIE: Or a flood type lamp.

FLATOW: Although they're making their reflectors now with fluorescents at the most now.

Prof. LESLIE: They are. And they do perform better, but they still may have some problem with heat. But the, you would definitely want that type of lamp in your high hat in order to get enough light out.

FLATOW: I've also noticed maybe this is me that, but even though, they say they're rated for 10 years. I have bulbs that are five, six, seven years old, but they're all the very older manufacturer ones, not the newer ones. They don't seem to last as long as the older ones.

Prof. LESLIE: Well, some of the newer ones are rated for 6,000 hours of burning. The manufacturers don't rate them in years because they don't know how many hours you're going to leave them on. And they don't know how often you're going to switch the light on and off. And the light of a fluorescent lamp is dependent on how often you switch it on and off. Frequent switching will shorten the life.

Now that doesn't mean that you shouldn't turn the light off. The rule of thumb I like is if you don't need the light for 10 minutes or more, and you want to consider the energy and the replacement cost, it's worth turning that light bulb off.

FLATOW: Let's go the phone. Let's go to Malcolm in Grants Pass, Oregon. Hi, Malcolm.

MALCOLM (Caller): Good morning, Ira. You partially answered one of my questions, which is about the longevity of the light because I built a new house about, I think, about I think 11 years ago where I put all lot of fluorescent bulbs and a lot of incandescents. And all of the fluorescents burned out before incandescence have.

Now, a part of it, a lot of them were in cans but some of them aren't. So, and I know they burned out first because they are on circuits, where I might have three incandescents and one compact fluorescent. But you partially answered that. But I'm wondering one thing, is how much embodied energy is in those bulbs? How much energy does it take to drive them to the recycling center in such as this? And also if I could, I wanted to point out, that if you are in an area that reheat your home, that light or the waste from the incandescent light bulbs helps heat home just as efficiently as an electric heater does, not if you have a heater (unintelligible) it's less efficient, but I don't - I think the claims of 75 percent or 80 percent savings are a little exaggerated.

FLATOW: Good points.

Prof. LESLIE: Well, we have a series of questions there. We like to recommend that you replace an incandescent with a compact fluorescent that's a third of the wattage, not a quarter as many people recommend and that is to compensate for some of the thermal differences that you might experience. In terms of the heating the home, that's absolutely correct, but any energy that you put in as light, unless it goes out the window, eventually becomes heat to your house.

MALCOLM: Right.

Prof. LESLIE: It also becomes, on the other hand though, if you are in area that requires cooling and you're not doing that naturally, you then are going to have that much more heat to extract with it.

MALCOLM: Very true, yes.

Prof. LESLIE: In terms of the lamp life, when you measure lamp life of a fluorescent lamp, the way it's determined is they look at a large sample of these lamps and they identify the point at which half of that large sample have failed completely.

So, it is possible that you had a bad sampling, bad luck and just got some of that died more quickly, but it's highly unusual that you would have that number of failures in advance of the incandescent. In terms of embodied energy, yes, there might be some differences there. But remember, if you're going to have 10 times the life, which is reasonable, we test these lamps for the government and for electric utilities and we find a lot of them, usually last longer than the 10,000 hours and some have last as long as 20,000 hours, some of the sample on the other end out the spectrum.

FLATOW: Malcolm, if you're using them in those high attics, they kill them.

MALCOLM: Yeah. (unintelligible) and kill them.

FLATOW: Let me tell you.

MALCOLM: Right. All right. How much is the cost of all these things (unintelligible)

Prof. LESLIE: (unintelligible) throwing away different lamps, you're throwing away 10 incandescent lamps.

FLATOW: What was that?

MALCOLM: I said, do people take these to recycling to get rid of them mercury and if they do, isn't there an energy cost to that? If you can't take them just dump it to the, you know, local (unintelligible or whatever you're doing?

Prof. LESLIE: Yeah. Well, in the last few months, there's been a huge effort through legislation and other initiatives to increase the use of compact fluorescent lamps in the home and it's really hitting the tipping point.

Many of these states have realized that they then have to have a better opportunity in order to deal with the remaining bulks. So, there will be a series of initiatives, I think it was Ikea, at some point, would receive the bulb at the store. I think you're going to see more of these things. You may see deposits in some states. You may just see when, you buy them by the case that you put them in the case and then turn in the whole thing afterwards.

FLATOW: We are saying more and more of these stores, the big box stores where you get, you know, where you buy them by the dozens, having recycling centers in them. We're talking about light bulbs this hour on TALK OF THE NATION: SCIENCE FRIDAY from NPR news. Our number, 1-800-989-8255.

Linda in Tucson. Hi, Linda.

LIANDA(ph) (Caller): Hi, actually Ira it's Lianda.

FLATOW: I'm sorry.

LIANDA: That's okay.

FLATOW: I need my glasses tuned up.

LIANDA: And I was one of the people who wrote to you and I'm so happy that you are doing this program. This is one of the most important issues because this is a trade of the lesser of two evils.

What incentives do these manufacturers have to develop new bulbs that are not highly toxic with mercury when there are making millions and millions of dollars? And the money they are making doesn't really reflect the true cost of these bulbs because, as you mentioned, these can even be brought to recycling centers. They're so highly toxic that they must be specially handled and there is no good way to store mercury.

FLATOW: Let me ask our guest. Professor Leslie, can you make a fluorescent without the mercury in it?

Prof. LESLIE: Well at this point you cannot. You can get better at the technology, which the lamp manufacturers have done over the last few years. The CFL right now has four to five milligrams of mercury in it, which is about the size of the tip of a ballpoint pen. If you compare it to a mercury thermometer, that has 500 milligrams instead of four or five or an older thermostat would have 3,000 milligrams. Nonetheless they're - they have gotten better and this promises to drop, perhaps, as low as two or three, but they have not found a way to produce light in that manner without at least a little bit of mercury, which they can improve upon by controlled dosages.

FLATOW: Or you could decide that we will pay that extra money and go with the LEDs.

LIANDA: Exactly.

FLATOW: Just for help(ph).

Prof. LESLIE: As long as that LED is providing the efficiency that you want because we are running with coal-fired power plants and that incandescent is pumping a lot more. In fact, it's over 50 percent more mercury into the air than a CFL...

FLATOW: Wow.

Prof. LESLIE: ...over its lifetime. So, it is - and I wouldn't necessarily call it the lesser of two evils. There's also a lot of benefits to lighting, which include health, safety, the ability to read and many other good things.

FLATOW: No one's telling us to go back to candles.

Prof. LESLIE: Right.

FLATOW: Thanks...

LIANDA: What about the bulbs exploding? And what about during recycling when these things break and then, it's released? You know, and we're talking about bulbs that, if these are going to be in every home, the small amount is going to be multiplied by millions and millions. So, there has to be an incentive for manufacturers to stop developing things that are toxic for us. That's my opinion and thank you so much for doing this program, Ira.

FLATOW: Thank you, Lianda.

Prof. LESLIE: Well, light bulb - compact fluorescents to my knowledge do not explode. They may be dropped and break as with any light bulb. And the EPA recommends some simple ways that you can clean it up. And the only thing they warn you strongly against is doing any kind of incineration with the bulb because that puts it in the air, the mercury vapor into the air.

FLATOW: All right. Professor, thank you for taking time to be with us.

Prof. LESLIE: Okay, you are welcome.

FLATOW: Russell Leslie is professor at Rensselaer Polytech Institute In Troy, New York. He is also the associate director of the Lighting Research Center there.

We're going to take a break, change gears and when we come back, we'll talk about all these fires that have been burning from East Coast to West Coast. What is the legacy? Are we going to see this happening more? Is any of this related to global warming, to droughts? What do you do? What do you replace the burnt stuff with? What do you plant? What happens? All kinds of questions and your questions. So, stay with us, we will be right back after this short break.

I'm Ira Flatow. This is TALK OF THE NATION: SCIENCE FRIDAY from NPR news.

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