This is an article from cnet.com
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.”
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. In places like Perth solar panels are vastly used by people cause it is exceptionally sunny and as using solar energy is good for the environment as well as light on the wallet.
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.
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, cleaning windows and carpets (which can be optmized too, click here to learn how), 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.