May 28, 2007 4:00 AM PDT

FAQ: 21st-century guide to indoor lighting

A correction was made to this story. Read below for details.

FAQ Thomas Edison's lightbulb has been lighting the world for more than a century, but its predominance is beginning to fade.

A new era of lighting is dawning, designed to meet the needs of a power-hungry and resource-challenged 21st century. There have never been so many options for illuminating the indoors.

"My crystal ball says that in five years, the home is going to be a mix of incandescents, LEDs and fluorescents," said Michael Siminovitch, director of the California Lighting Technology Center at the University of California at Davis.

As prices drop for alternative lighting in the coming years, consumer options will proliferate. Today's technological innovations make Edison's work look like the stuff of a middle-school science fair. Compact fluorescents are looking lovelier, white LEDs last a decade, organic LEDs make ceilings and countertops glow, and fiber-optic tubes can pipe true sunshine from roof to cellar.

"The lamp aisle in stores is already a mile long," said Siminovitch. "It's gonna be confusing."

Incandescent lightbulbs

What: Since General Electric patented tungsten bulbs in 1906, the core technology hasn't changed much. Incandescent lightbulbs exclude oxygen from a soft glass chamber, in which an energized tungsten wire releases photons, or light. Halogen lights work similarly, but a halogen gas keeps them burning brighter, hotter and longer.

To environmentalists, incandescent lightbulbs are looking less like the bright idea they have come to symbolize. Traditional bulbs could be phased out in the United States over the next decade. Australia and the Canadian province of Ontario are set to ban them.

"In 10 years you won't be able to buy energy-wasteful incandescent bulbs," said Eric Corey Freed, architect and founder of Organic Architect, in San Francisco. "It'll get to the point where we'll each be responsible for the energy we consume because it leads to carbon emissions and global warming."

Pros: Old-school lightbulbs are cheap, easy to find, and come in an array of shapes and sizes that fit most light fixtures. They turn on instantly and emit a full spectrum of light to mimic the sun's rays.

General Electric is designing incandescent bulbs to be as efficient as compact fluorescents by 2010.

Cons: Antiquated incandescents waste 90 percent of their energy as heat and burn out in as little as 750 hours. This energy inefficiency can cause painful utility bills for individuals while demanding more production from power plants, one-third of which are coal-fired.

Lighting makes up as much as 20 percent of power consumption in U.S. households, according to the Department of Energy. The Natural Resources Defense Council estimates that switching every home to compact fluorescent bulbs would prevent the release of 1 trillion pounds of greenhouse gases into the atmosphere.

In addition to ecological and economic concerns, the heat given off by incandescent bulbs can make it hard to keep a house cool on hot summer days, leading to higher air conditioning costs.

Even worse, halogen bulbs pose dangerous fire hazards and are too hot to handle. Merely touching quartz halogens leaves bodily oils on the surface of the lamp that can lead to an explosion.

Compact fluorescent lightbulbs

What: Fluorescent lighting involves chemical reactions in which phosphor powder glows when energized by gases that include mercury.

Pros: Fluorescent lights have come a long way since the 4-foot tubes common in industrial ceiling fixtures. Compact fluorescents, or CFLs, come in an array of colors, sizes and shapes and at prices low enough for big-box stores like Wal-Mart and Target to give them prominent shelf space.

"Fluorescents coming onto the market in the next year to five years are going to be incandescent-like," said Siminovitch.

Compact fluorescent bulbs in corkscrew, globe and spotlight designs fit into most light sockets, and many now work with dimmer switches. More CFL-friendly lamp and chandelier styles are also coming onto the market as bulb makers reduce the bulbs' telltale buzz and flicker.

CFLs fade gradually when they die, indicating when a replacement is due. Because fluorescents last at least 10 times longer than tungsten bulbs, however, a replacement might be necessary only every few months or even years.

Fluorescent bulbs are 90 percent energy efficient, nearly the reverse of incandescents. Although CFLs contain poisonous methylmercury, environmental groups contend that the energy efficiency reduces pollution by letting polluting power plants relax.

Cons: It's illegal in seven states to dump mercury-laden fluorescent bulbs with the regular trash. Yet lightbulb recycling options are hard to find. Mercury-free alternatives include ceramic metal halide or xenon fluorescents, but these remain rare and less efficient. However, members of the National Electrical Manufacturers Association have pledged to cap the amount of mercury in CFLs at 6 milligrams per bulb. Wal-Mart is planning to reduce the amount of mercury in its compact fluorescents by 30 percent.

Siminovitch recommends buying Energy Star-rated bulbs for the best quality. "We devalue this technology by going into the store and buying the three-pack for two dollars," he said.

Some fluorescent bulbs can take several minutes to warm up and don't operate well in freezing or very hot temperatures. Their cool, narrow-frequency light doesn't appear warmer when dimmed. And without ultraviolet filters, fluorescent bulbs can damage colors in artwork and fabrics.

Many CFLs cost twice to three times more than their incandescent counterparts, a barrier for bargain shoppers. Broader-spectrum CFLs may be more expensive. But these bulbs recoup their cost over the long-term through reducing electrical consumption.


What: Light-emitting diodes are solid-state semiconductors. In LEDs, light shines from a chip rather than passing through a bulb or tube. OLEDs, on the other hand, are made with an organic laminate that glows when energized.

Alarm clock LED displays are the grandparent of today's multipurpose LEDs. After the blue variety came along in the 1990s, engineers were able to combine them with red, green and yellow LEDs to create a beam of white light with potential beyond their use in a host of electronic gadgets. Even more recently, quantum dot nanotechnology is helping to create broader-spectrum LEDs with less of a blue hue.

Pros: LEDs turn on instantly, dim easily, and deliver a focused light ideal for a precise space, such as a desk. Because LEDs come in many colors, filters are unnecessary. The small size makes LEDs ideal for creative uses, such as lining bar counters and staircases. Ultra-durable LEDs are increasingly common in flashlights and traffic lights and will be found increasingly inside of household appliances. And rather than burning out instantly, LEDs dim gradually.

LED lights generally use one-tenth the energy of an incandescent bulb and can last a decade or longer, but without the poisonous mercury found in fluorescents. Prices will likely drop and availability will increase as solid-state lighting becomes cheaper to manufacture. The nanocrystals that make up the newest white LEDs can be grown chemically in a lab, and organic LEDs can be printed.

OLEDs could be used to create phosphorescent ceiling tiles, furniture, curtains and more. Tech manufacturers currently use OLEDs in MP3 players, mobile phones, monitors and printer displays. Unlike LCDs, they don't require backlighting and they demand little energy.

Cons: For now, few people are willing to spend upwards of $15 on an LED lightbulb or to track them down in specialty stores.

LEDs waste less energy than incandescents but more than CFLs. That's why leaving a microwave plugged over its lifespan can eat up more power than it uses to cook.

LEDs also contain inorganic compounds such as toxic gallium arsenide, which hasn't been thoroughly studied.

OLEDs are still being perfected in laboratories and are likely to reach a broad market within a decade.


What: Many lightbulbs are designed to mimic the sun's glow, but daylighting pipes in real sunlight from the outdoors. Hybrid solar lighting technology collects sunshine from a rooftop and channels it indoors through reflective fiber-optic tubes. On the roof, mirrored domes may shift according to the sun's location in the sky.

Less complex daylighting systems are also available. Architect Freed, for instance, creates sun tunnels by connecting a skylight to a tinfoil hose that snakes into a dark corner. The result looks like a light fixture, but it dims when clouds or birds pass overhead.

Pros: Daylighting is attractive for spaces that lack windows. Unlike skylights, fiber-optic solar lighting directs beams to specific locations in a room, and the flip of a switch can cut off the flow.

Such a setup delivers the equivalent light of 17 fluorescent lamps, according to manufacturer Sunlight Direct.

In sunny climates, next-generation daylighting systems could save a business or household many thousands of dollars in energy costs per year. Daylighting may also lead to better health. Various studies connect natural sunlight with mood boosts, higher test scores in schools, increased productivity in offices and better sales in stores.

Cons: Sophisticated daylighting systems aren't yet widely available for homes, and despite the long-term utilities savings, installation costs are prohibitive. For instance, Solatube, which uses tubular skylights, charges a household $200 and up per 200 square feet.

When the sun goes down, so do the lights. Since sunlight can't be stored well, electricity is needed at night and even on gray days. Although filters can adjust the color temperature of the incoming lighting, the rays may look redder in the mornings and evenings along with the sun's cycles.

The reach of daylighting systems is limited as well. Solatube's systems can extend 50 feet, but that's not enough to keep a skyscraper from going dark. Daylighting companies are racing to compete with more reflective tubes, precision dimmers and other innovations.

Lighting controls

As bulb alternatives put a slew of new choices into consumers' hands, new lighting controls offer additional options for conserving money and power. Dimmer switches, timers and occupancy sensors can save a household hundreds of dollars a year--especially in kitchens and bathrooms, where people tend to leave the lights on during the day.

And aside from changing bulbs or splurging on next-generation technologies, quick fixes such as hanging mirrors and cleaning windows can maximize indoor lighting, said architect Freed. More architects are following his path of designing buildings that maximize available natural light instead of relying upon electricity to supply it.

"If we can crawl before we walk, we'll be fine," said Siminovitch of UC Davis.


Correction: This article mischaracterized how incandescent lightbulbs work. They keep oxygen outside the glass chamber to generate light within.

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Join the conversation!
Add your comment
Get the science right
Someone should run articles that contain scientific information
past a scientist before it's released.

1) Incandescant bulbs aren't filled with oxygen. That burns the
filaments out! They have traces of oxygen but are filled with
argon at very low pressure usually.

2) There are no "chemical" reactions going on in a flourscent
bulb. The very low pressure mercury gas is ionized by the
voltage differential across the tube. This produces ultraviolet
light. Most of the ultraviolet light strikes the powdery lining of
the flourscent tube where it produces "flourscence" by being
absorbed by the powder and re-emitted as visible light. That's
why they call it a flourscent light! It flouresces! No chemical
changes, just electrons being captured and changing state.
Posted by woo37830 (8 comments )
Reply Link Flag
Someone has to ride herd on these news cowboys. Thanks for
making the effort!
Posted by billmosby (536 comments )
Link Flag
chemical reaction.
"The very low pressure mercury gas is ionized by the voltage differential across the tube. This produces ultraviolet light. Most of the ultraviolet light strikes the powdery lining of the flourscent tube where it produces "flourscence" by being absorbed by the powder and re-emitted as visible light. That's why they call it a flourscent light! It flouresces! No chemical changes, just electrons being captured and changing state." - I believe you are describing a type of chemical reaction.
Posted by migswell (25 comments )
Link Flag
incandescent bulbs EXCLUDE oxygen
You got the basis for the incandescent bulb backwards - the trick
Edison required to make them work was to exclude oxygen. They
hold a vacuum or an inert gas such as nitrogen or argon.
Posted by mdjacobson (4 comments )
Reply Link Flag
Thank you
The error has been corrected.
Posted by stevenmusil (82 comments )
Link Flag
Guide to Indoor Lighting
What about the health effects of CFL's.

I've read some awful things about CFL's in connection with health hazard, e.g., radiation of a variety of harmful rays as well as harmful effects of artificial light on your body which according to certain studies by a Dr John Ott, natural light is needed and the incandescent is fairly close whereas the CFL (even the new and improved versions) give appearance of near natural but fall way short.
Posted by globalview99 (6 comments )
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Dr. Ott
I believe that his company sells some form of these lamps with the supposed property of duplicating solar light.

Our house is using some form of gas discharge fluorescent lamps in every fixture. The only hot filaments are in the microwave, oven and fridge. Oh, we do have a movie light that is quartz iodine. 99.9% of our light is green.
Posted by bigduke (78 comments )
Link Flag
LEDs waste less energy than incandescents but more than CFLs.
The author states "LEDs waste less energy than incandescents but more than CFLs." How can this be, if CFLs use approximately 1/3 the electricity of an incandescent bulb and "LED lights generally use one-tenth the energy of an incandescent bulb"?

Is the author comparing apples (LEDs left on 24 hours/day) to oranges (CFLs turned off most of the time)? If an LED uses 1/10th the energy of an incandescent, shouldn't a 60 watt output LED use roughly 1/3 the electricity of a comparable CFL?
Posted by Bear12291959 (1 comment )
Reply Link Flag
The author is right
LED's are in general more efficient than CFL's but, the way they are
used will determine the true efficiency. This is just a fact of the
technology used. They author's statement should indicate that
LED's use 1/10 th of the light to output the same amount of light
as an incandesent while a CFL uses 1/3 to output the same amount
of light. This would make LED's more efficient.
Posted by BrandonEubanks (33 comments )
Link Flag
No, it's just complicated
Some LEDs are more efficient than some flourescents, but not all. This article and table gives you all the gory details:
<a class="jive-link-external" href="" target="_newWindow"></a>
Posted by guinnessgulper (2 comments )
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combining LEDs to make white
When white LEDs first came out they were just blue LEDs with a phospher coating. It didn't take long for them to start to get a blue color to them. The author implies they are now made out of different colored LEDs but still get a blue hue? That doesn't sound right. Plus, if you have a red, a green, and a blue LED, why do you need a yellow one to make white?
Posted by summershoe (41 comments )
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Has the level of science dropped to this level???
Incandescent bulbs don't "trap oxygen outside" -- how can you "trap" something outside??? The most accurate and clear way to describe them is that they employ a partial vacuum inside the bulb to exclude oxygen, so the tungsten filament can glow without burning. This was science I learned in junior high school, I'm sure. Is the general level of scientific literacy now so low that some ackward utterly dumbed-down description of a simple concept needs to be supplied? I mean, after all, this is a *tech* news site -- even if the average American is scientifically illiterate &lt;shudder&gt; can't we at least assume scientific literacy here? Or is the issue the authors, not the audience...???
Posted by baisa (126 comments )
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Re: Has the level of science dropped to this level???
Ok the 3rd time is a charm, while early bulbs did use a vacuum to prevent the filament from burning, modern bulbs use a inert gas.
Posted by k2dave (213 comments )
Link Flag
Several incorrect statements have already been noted by others, here is an additional one.

The amount of energy cosumed by the LEDs in a Microwave oven over several years would probably be about ten percent of that required to cook a casserole. The statement in the article was completely ambiguous.
Posted by c.v.parker (2 comments )
Reply Link Flag
Correct the correction please
Oxygen is not trapped outside; an inert gas is substituted which allows the tungsten filament to glow rather than burn out. The earliest light bulbs used a partial vacuum; hense the rather spectacular failures of early bulbs. Halogen bulbs are vacuumed and gasses such as krypton, nitrogen and hydrogen bromide are added to the capsule under pressure.
Posted by fshattuck (11 comments )
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led's are more efficient
hands down.
Posted by migswell (25 comments )
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My LED pros and cons
I should start by saying that I own two LED bulbs, and spent around $70 for the pair (taxes and shipping/handling included). I got the most powerful bulbs I could find, so ended up paying a hefty premium over the $15 that is mentioned in the article. At present, you don't get much brightness for $15.


* Even at the horrendous purchase price I paid, and assuming that electricity costs stay the same or increase over the next couple of decades, the energy savings over the estimated 60,000 hour lifetimes of the lamps will net me at least several hundred dollars that I wouldn't have had in my pocket, had I used incandescent bulbs instead.

* The LED lamps run remarkably cool. I don't have to worry about leaving them on for long periods by mistake, putting them in proximity to flammable materials, the cat knocking them over, touching them inadvertently, etc.

* I can leave the lamps on all day and night (though I usually don't), and still consume less energy than leaving similarly bright incandescent lamps on for just an hour or so. So far, I have been using only one lamp at a time, and have already seen a significant drop in my household's daily average kWh consumption. It will be interesting to see how this translates into savings on my utility bill.


* The brighter lamps available to me only seem to come in the "cool" color temperature range, which makes them seem much like traditional fluorescents (without the buzz of faulty button exciters or the "strobe effect"). I'd like to try some "warmer" light, but the ones I can find so far only seem bright enough to use as nightlights or accent lighting.

* Even the brightest lamps I can easily find are not that bright. The "spotlights" and "floodlights" seem comparable to 50-60 watt incandescents, maybe 75 watts at best. I'd have no problem spending $20-30 to get a direct LED replacement (in brightness and color temperature) for a 100 or 150 watt incandescent. They just don't seem to be available. To get decent overall brightness, you must use multiple bulbs.

* In my limited experience, the advertising material and package labeling for LED bulbs does not give sufficient information to do an "apples-to-apples" comparison between incandescent, CFL, and LED prior to actual use. I have two C-Crane bulbs, the CC Vivid+ and the CC Vivid Spotlight Par 38, purchased from two different retailers. The Vivid+ is allegedly much brighter than the CC Vivid 2, and the spotlight 3 times brighter than the Vivid+, judging only by the posted lumen ratings for the three bulbs. On C-Crane's website, they compare the dimmest of the three, the Vivid 2, with a 60 watt incandescent, for purposes of calculating lifetime costs of LED bulbs vs. those of incandescents. But in my experience, the Vivid+ provides as much light as I am used to getting from a 25-40 watt incandescent bulb, while the spotlight, as I said above, provides light that seems roughly equivalent to what I get from 50-75 watt incandescents. So there is no way that you would use a Vivid 2 in the same context as a 60 watt incandescent -- unless the 60w was major overkill for the application. The advertised cost comparison is not at all apples to apples. Perhaps you might replace a 60 watt bulb in a desk lamp with a Vivid 2 and be satisfied. But in that case, you could also replace the 60 watt bulb with a 25 watt incandescent bulb and be happy. Even talking about a limited, "reading lamp" application, I think that's a stretch.

* Not all available LED bulbs are recommended for use with dimmers, and even the dimmer-capable ones definitely don't work with three-way bulb step switches (that is, they do work, but not any more satisfactorily than a regular bulb works in a 3-way socket). Also, because even the brightest bulbs aren't that bright to begin with, it often makes little sense to use a "dimmer," unless you are controlling a bank of such bulbs.

The trick seems to be finding an application where the amount of light given off by the LED bulbs is appropriate for the intended purpose: then, you can start to figure cost savings over incandescents by doing apples-to-apples comparisons. I currently have a spotlight mounted in a desk lamp, aimed at the white wall behind me. This dimly lights my living room via light reflected from the wall, and makes the room bright enough to read by, if you are sitting in the corner of the room where the lamp is. By swiveling the desk lamp to point directly at something in the room, you can illuminate that thing fairly well, at the cost of plunging the rest of the room into semi-darkness. I'd love to be able to switch out the 3-way floor lamp bulb with something that would give equiavlent light, but the Par 38 spotlight bulb won't cut it. So I use the incandescent floor lamp in the early evening, when the rest of the family is up, and switch to the LED later on, after everyone else has gone to bed, if I have late night TV watching or reading to do. Even so, as I said, using this one bulb in this way has cut my average daily household usage by a significant amount, about 5% so far.

I hope the material above has been helpful. If anyone knows of a supplier for true incandescent replacement LED bulbs at reasonable prices (reasonable by LED standards, at least :-), please post here!
Posted by James Anderson Merritt (251 comments )
Reply Link Flag
Just wanted to thank you for the useful feedback even though I get
the feeling 99% of followup comments here never get noticed by
the original posted, especially after a day or two goes by.
Posted by sjkx (49 comments )
Link Flag
I'm so dissapointed...
***? 19 comments and nobody has bashed President Bush or mentioned the war in Iraq yet?

Here I was all set to rebut the evirowhacks with my "green is the new red" diatribe, and all I get is an on-topic technical discussion and definitions of chemistry.

Fine, I'll stir the stew: A chemist is a failed physicist!

There, I said it.
Posted by Wesley_Mouch (16 comments )
Reply Link Flag
not to mention Disappointed.
My fingers are dyslexic when my brain hasn't had coffee.
Posted by Wesley_Mouch (16 comments )
Link Flag
LOTS OF INFO, why yellow is used in white LEDS
<a class="jive-link-external" href="" target="_newWindow"></a>
Posted by Babak Rezai (5 comments )
Reply Link Flag
bought 8 LED's (CC VIVID 120 V 18 LED) at $18.95 each last 04/10/09 - used as vanity lights in my bathroom.
so far i've had 3 bulbs burn out, averaging one bulb burning out every 4 months.
since the bulbs are still under warranty i did not have problem getting a replacement but i question the
advertised super long life.
this is a very expensive investment.
Posted by prnmd (1 comment )
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