"L-E-D". When it comes to lighting, you're hearing these three letters over and over again... you see it posted all over lighting websites, and its starting to bug you. It seems to be an exciting new trend...some kind of new innovative light...but you have no idea what it is. You'd like to know what everybody's talking about- what's all the rage?
LED's - Light Emitting Diodes - Simply put, LED's are diodes that...(huh?) hang on, I'll explain: a diode is the simplest sort of semiconductor device. (what's that?) wow, you're impatient: A semi-conductor is a material with the ability to conduct electrical current. Basically, instead of emitting light from a vacuum (as in an incandescent bulb) or a gas (as in a CFL), LED emits light from a piece of solid matter, its semi-conductor. Stated very simply, an LED produces light when electrons move around within its semiconductor structure.
They tell you when to stop and go. They have ruled your driving, saved your life countless times, and that little red man made you wait around till you were able to cross the street. That's right - the red, yellow and green on the traffic lights are Led lights right in front of your nose. In fact, Light Emitting Diodes have been around for some time, conceptualized in 1907. However, it wasn't until the 1960s that practical applications were found and LED's were first manufactured. LED used to be used exclusively for traffic signals, brake lights and headlights on luxury cars, and indicator lights on appliances. You probably didn't even know that LED lights were lighting up your digital clocks, flashlights and telling you when you've got a new voice message on your cell phone. Expensive at the start, as applications grew, benefits were discovered and manufacturing costs went down. According to the American Lighting Association (ALA), lighting manufacturers have invested considerable time, effort and research into adapting this super energy-efficient technology for household use. The technology has advanced enough to win approval from the government's popular and well-respected Energy Star� program. So here's why:
- They do more for less. LED's are efficient-producing a lot of light from a little power. For example, one 5-watt LED can produce more light (measured in lumens) than one standard 75-watt incandescent bulb. The 5-watt LED could do the job of the 75-watt incandescent at 1/15 of the energy consumption. LED's save energy and, therefore, money. This is because in LED lights, 90% of energy is converted into light, while in incandescent bulbs 90% of energy goes to heat and only 10% to visible light.
- They last longer. LED is virtually maintenance free - they don't have a filament that will burn out, so they last much longer. A standard "long life" household bulb will burn for about 2,000 hours. An LED can have a useful lifespan up to 100,000 hours! By some sources, LED's can last for as long as 40 years. Imagine not having to change a light bulb for years. There are LED products available this year that will make frequent light bulb changes so 20th century.
- How it actually works... (skip this part if you don't really care) Light is a form of energy that can be released by an atom. It is made up of many small particle-like packets, called photons, which are the most basic units of light. LED's are specially constructed to release a large number of photons outward.When an electric charge strikes the semiconductor, a small electrical current, which is measured by watts (oh! so that's what they mean by 'has low wattage'!) is passed through the semiconductor material. this causes the electrons to move around, become "excited" and give off photons. Almost all of the energy emitted is light energy. In an ordinary diode, such as incandescent bulbs, the semiconductor material itself ends up absorbing a lot of the light energy so it produces more heat energy than light energy.This is completely wasted energy, unless you're using the lamp as a heater, because a huge portion of the available electricity isn't going toward producing visible light. LED's generate very little heat, relatively speaking. A much higher percentage of the electrical power is going directly to generating light, which cuts down on the electricity demands considerably. As you can see in the diagram,they are housed in a plastic bulb that concentrates the light in a particular direction. Most of the light from the diode bounces off the sides of the bulb, traveling on through the rounded end.
- They are a better buy (in the long run). Up until recently, LED's were too expensive to use for most lighting applications because they're built around advanced semiconductor material. The price of semiconductor devices has plummeted over the past decade, however, making LED's a more cost-effective lighting option for a wide range of situations. While they may be more expensive than incandescent lights up front, a 60-watt LED replacement bulb runs in the area of $100, and even the lower-output versions, used for things like spot lighting, will cost between $40 and $80. That's compared to a $1 incandescent and a $2 fluorescent bulb.The reality is, even at $100 for a single bulb, LEDs will end up saving money in the long run, because you only need one or two every decade and you spend less money on home lighting, which can account for about 7 percent of your electric bill [source: Greener Choices]. But don't worry, the scary price you need to pay upfront won't last too long, the lighting industry in general expects LED costs to come down quickly. Lighting Science Group, a company that develops and manufactures LED lighting, estimates a 50 percent price reduction within two years.
- It looks nice. The prime replacement for the incandescent light bulb would be the higher-efficiency compact fluorescent, or CFL. However, besides that there is toxic mercury in the design, it gives off a strange, sometimes unpleasant color that even gives some people headaches. Not the LED- its light is easy to see even in bright sunlight and can produce the same soft, white light as a regular bulb. (Although Energy Star does recommend looking for the Energy Star label when shopping for LED bulbs, since the organization tests for color stability as part of its certification criteria.) Here's the coolest part about LED's - they can be illuminated and change its light to many colors including a very recent addition of White and Blue. Other are Green, Red, Orange and Amber.
- It's Safe. LED requires low voltage DC electric current and can run on batteries, so it's safe to the touch - it doesn't get hot.
- It's Strong. LED's are durable - they aren't glass but small plastic bulbs.
- It's Swift. LED's are easy to implement - they are just tiny bulbs that fit easily into modern electric circuits. Additionally, because of their size, more bulbs can be used on an electrical circuit.
- The Rage. LED will lead and light up the future. The light bulb that has lit up our homes since the 1800s is officially on its way out. The inefficient incandescent, has fallen out of favor with the financially and ecologically concerned; starting in 2012, U.S. residents won't be able to buy one even if they want to [source: Linden]. The government is taking the little energy suckers off the market."This year 2010, will be the first year where LED's will explode in the residential marketplace," says architect Joe Rey-Barreau, education consultant for the ALA and an associate professor at the University of Kentucky's School of Interior Design. "We are already seeing amazing LED developments in all parts of our lives, from Christmas lights to LED TVs. One area where LED's will become predominant in 2010 is the category of desk and task lamps," Rey-Barreau says. "Another major development will be in replacement bulbs, as the extreme long life of an LED bulb makes it ideal for replacing recessed lights in hard-to-reach areas such as vaulted ceilings in living rooms or kitchens". If you aren't sure yet if you want to devote a large portion of your living space to the technology, Rey-Barreau suggests trying under-cabinet lighting in the kitchen, a desk or task lamp or path lighting outside to see if you like the illumination it provides before investing in an entire ceiling of recessed fixtures or a large chandelier.