LEDs, or light-emitting diodes, were created to lend a helping hand. Forty years ago the little-lights-that-could told you when your household appliances were on and helped you tell the time. Uses for the early versions of these semiconductors were limited by their ability to produce only the colors red, yellow and green -- perfect for stoplights, electronics and exit signs, but not overly useful in most daily residential applications. Then, illuminated life as we knew it changed virtually overnight. Shuji Nakamura, a Japanese scientist, created the world’s first blue LED, which, when mixed with phosphors, produces white light. This discovery, made in the 1990s, paved the way for LED technology and infinitely increased its possibilities for applications both inside and outside the home.
“The most exciting thing that’s happening is that LEDs are changing the industry and changing how [we] interact with lighting,” says Paul Vrabel, director of Energy Efficient Products Group at Sea Gull Lighting and Generation Brands partner Monte Carlo Fan. “It’s a truly disruptive technology, probably synonymous with going from punch cards in computers to using a microchip or going from a rotary dial phone to a cell phone that fits in your pocket. In the future, you won’t buy a light fixture with a [separate] screw-in light bulb. All of a sudden, you buy a lighting system, and the LEDs are incorporated into it and everything is together.”
As they attract more of the national spotlight, LEDs are beginning to catch on with the general public, sneaking into homes under several different guises. LED Christmas lights, a perfect application for a monochromatic light source, seemed to be on everyone’s wish list this past holiday season. GE released a statement that retailers stocked 34 percent more LED light strings in 2008 than in the previous year.
The potential for LEDs continues to grow in more practical uses throughout the home, as well.
“One application in which LEDs are very much in practice at this point is downlighting,” says Marc Ledbetter, manager of the Emerging Technologies Program at the U.S. Department of Energy’s Pacific Northwest National Laboratory. “It’s going to vary by home and geographic location as to whether that application is cost-effective, but the price is coming down significantly on some of these high-performance residential LED products.”
According to Ledbetter, downlights are an effective application for LEDs because they take advantage of the directional nature of the light. Similarly, other LED characteristics, such as their small size, lack of infrared heat and long lifespan, make them a sensible choice for undercabinet, accent and task lighting.
LED technology is also finding a home in the great outdoors. According to McGowan, LED floodlights and landscape lights -- many of which come equipped with smart features like occupancy sensors for added energy-efficiency and safety -- have recently seen marked advances.
“I have seen LED landscape lighting come a long way this year,” McGowan says. “I bought some and put them in the backyard as my own little experiment. The light is a little low, but we will be seeing better output, adjustability and ease of use [in the near future].”
One of the most attractive aspects of LED technology continues to be its potential to save massive amounts of energy. According to the U.S. Department of Energy, LEDs’ annual energy savings in 2007, as studied in twelve niche markets, was about nine terawatt-hours, which equals the annual electrical output of 1.4 large coal power plants. The decrease in energy consumption saved consumers almost $1 billion in electricity costs last year. As the technology behind LEDs continues to improve, the energy savings is certain to increase.
LEDs are currently as efficient as compact fluorescents, but many experts believe that the new technology will eventually surpass its energy-efficient predecessor. According to Vrabel, LEDs will soon emit more than 100 lumens per watt, while, even at their best, CFLs reach only about 75 lumens per watt.
“The improvements on LEDs continue at a very quick pace,” Ledbetter says. “We’re seeing at least annual, significant improvement in the amount of light emitted from a single LED. We’re also seeing improvement in the efficiency with which the products can produce light, and we’re seeing improvement in the quality of light that’s being emitted.”
Although exciting, these sudden advances in LED technology are a cause of concern for those in the industry. Rapid improvements have left little time for regulations and adequate testing.
“[As a result], there’s a lot of inconsistency, a lot of unknowns around LEDs,” Vrabel says. “The industry -- everyone from the trade associations and technology experts to those who help write standards and specifications and testing procedures -- is figuring out how we put this together so that we can get the life out of it that is expected. How do we test it to make sure it’s going to last? When you buy a car, they tell you how long the motor will last or how long they are going to warranty the motor because they know how long certain parts will last. With LEDs, those standards are just becoming available now. That’s the biggest challenge. There are a lot of technical challenges and testing standards that need to be developed.”
McGowan agrees that more testing and structure must soon be added to the market. There is a lot of buzz around LEDs, and people are excited about their energy-saving potential, despite knowing little about how they actually work. Claims of “no heat” and “lasting forever” are top of mind for many consumers, Vrabel says, but most people do not understand the current limitations of LEDs. Many are unaware that, in terms of general household illumination, LEDs are still falling short. And for consumers who are excited about putting this emerging technology to quick use, some run the risk of becoming disappointed and frustrated with products that don’t live up to their hype.
“That is an issue that varies by manufacturer,” Ledbetter says. “There are a large number of LED manufacturers that currently sell fixtures that are prone to failure, or are prone to rapid lumen depreciation or prone to poor color quality. On the other hand, there are a number of manufacturers that are making very good products that perform very well with regard to lumen depreciation. It’s extremely important that people who are purchasing the technology at this stage of its commercialization ask a lot of questions about the performance characteristics.”
For now, it all comes down to applying LEDs to the appropriate usage. While general illumination still has a ways to go, in the realm of task lighting and undercabinet fixtures, LEDs are making some real headway. In these types of applications, LEDs can be twice as efficient as CFLs.
The measured growth in the residential market may be, in part, due to low demand. LED has made great strides in lighting parking lots and parking structures in the last year, Ledbetter says, but getting LEDs into homes is an entirely different beast.
“The residential market has been much slower to respond than the commercial market,” Vrabel says. “The technology will definitely mature in the commercial market. For the residential market, you have some early adopters, but as far as putting it in most homes, builders [are hesitant]. Right now, the market is so beaten down that builders are trying to make affordable homes for people because everyone [is feeling the stresses of the current economy].”
In the meantime, consumer education is a big issue, according to both McGowan and Vrabel. After all, an educated consumer is the best consumer—but that may mean starting from scratch.
“When it comes to lighting, Americans just don’t know [much],” Vrabel says. “Everyone thinks a watt is the measure of the amount of light that is given off by the light bulb, and that’s not true; it’s the lumen. The American consumer has never been taught about lumens per watt, which is key to understanding efficiency.”
In addition, cost is going to be an issue, no matter how far the technology comes. Right now, it’s the main complaint among consumers, retailers and builders.
“Cost is a big one,” Ledbetter says. “It has to come down for the product to be more attractive to consumers and more cost-effective for the range of applications in the residential spectrum.”
Cost and efficiency go hand-in-hand. According to Ledbetter, as the light source becomes more efficient, you need less LEDs to do the job. So, you can solve the cost equation by making the product more efficient.
Despite formidable challenges, the future is bright for LEDs. McGowan says that virtually every dollar being spent by the Department of Energy is going towards LED technology, and most lamp manufacturers, including bigwigs like GE and Philips, are on the LED bandwagon. Now, there just needs to be a better way to get the word out to the consumer.
“People in the industry are asking the same questions,” McGowan says. “We have to organize in some better fashion than we are right now. [By not fully embracing the advantages LEDs have to offer residential lighting], we are shooting ourselves in the foot at a time when we could really use every dollar of a sale.”
-- LEDs have a long life, but like all light sources, they slowly fade over time.
-- LEDs do not radiate infrared heat, only visible light. However, waste heat is produced during the conversion from electricity to light and may harm the LEDs if it is not properly removed from the lighting system.
-- By any measure, illuminance or luminance, LEDs have enough light output for use in even very large outdoor daylight-visible installations.
-- The ROI for the use of LED lighting systems in an installation is surprisingly rapid when taking maintenance and energy cost savings into consideration.
Source: “The Seven Great Myths of LEDs,” Philips Solid-State Lighting Solutions