More and more homeowners are turning their eyes towards LED bulbs as a technique to save energy. But will you really get the best efficiency by buying this still expensive alternative right away? Or is it better to wait, or to buy other energy-efficient lighting, and use the savings that generates to buy LED house lights later?
You have most likely seen LEDs already: camping headlamps, LED Christmas tree lights, wind-up emergency flashlights. How about LED house lights? If LEDs use so little energy, why aren't manufacturers scrambling to sell LED lights for the home, and why aren't consumers scrambling to buy them?
I wouldn't try to sell you on LED lights as a way to address high energy bills or as the most environmentally beneficial lighting solution around. In fact, I think LEDs have a stretch to go yet, in terms of light strength, durability, and price. There are some LED applications you should invest in now, such as LED Christmas lights. And you might enjoy testing out one or two LED lights, if you're the energy-saving type. But you are going to do better keeping with your existing lighting, and moving over to fluorescent lighting in the short term. Compact fluorescent lights, or CFLs, will pay for themselves before LEDs have improved enough to make CFLs obsolete.
LEDs are more efficient than incandescent or fluorescent bulbs. But LEDs have very directed light. An incandescent bulb shines over a wide area quite evenly, while LED bulbs are very focused, so that the area they directly illuminate is very bright, while the further you go from the direct beam, the fainter the light. For LED Christmas lights, that isn't an issue; you just want some bright points of light, which LEDs do very efficiently. But an incandescent or CFL will do a much better job of lighting your dining room than an LED bulb in the same fixture. The light will be more evenly and broadly spread, and with a warmer color temperature.
When you see LED merchant claims of LED light output, you should be suspicious. A rating in Lumens, which indicates brightness, is misleading for LEDs, because of their focused beam. Lumens levels are measured using a sensor placed immediately below the light source. A household LED bulb at 2 watts could have the same lumens rating as a 50 watt incandescent lamp, or as a 15 watt compact fluorescent, but the LED bulb may only send a focused light directly below it to the photo sensor, while the incandescent bulb and compact fluorescent will light up a much broader area, and still give that same lumens measurement for the area immediately beneath the bulb. This could be the source of a frequent negative comment among LED purchasers, such as: "The packaging claims this 2-watt LED light is equivalent to a 50-watt incandescent but it seems closer to a 30-watt incandescent bulb to me."
When it comes to halogen lights, they are only as energy efficient as incandescent bulbs, so the same energy efficiency considerations apply here. But since halogen lights are generally much more focused than incandescent lights, LED house lights that are made to be swapped in to replace halogen lights are both more efficient than the halogens they replace, and work well for the direct lighting that halogen bulbs are known for. You can purchase LED replacements for the most common halogen bulbs such as GU10 and MR13, and here's where you may want to start the switchover.
LED house light designers work around the problem of the narrow beam of a light emitting diode, by designing household LED bulbs that are a collection of individual LEDs, with each LED aimed at a different angle, so that a wider area is highly illuminated. This increases the angle of full light provided by an LED light. However very few such bulbs provide the breadth of area coverage of traditional incandescent bulbs or CFLs and at the same time match their total light output.
Where LED lights are an improvement over existing bulbs is as replacements for lighting that is (or should be) highly directed. For example, a light in a narrow hall, where the chief point of the light is to show people their way from one room to another, would be a good use of LEDs.
Task lighting is another area where LEDs are suitable. Why light up your entire workshop if all you need to see is the tools on the work bench right before your eyes? A couple of LED bulbs hanging above the work bench will do the job. But you can only cost-justify this in energy savings if you live half your life in the workroom.
LED lights are, in theory at least, very reliable, when compared to incandescent bulbs and CFLs. LED bulb life ranges from 35,000 to 200,000 hours, versus 1,000 hours for an incandescent light, and 8,000 hours for a CFL. But I have seen consumer reviews of LED lights that report burn-out within a few weeks of installation. So there are quality control issues still to be resolved - again, this is a good reason for holding off a year or two before a major conversion to LEDs.
Whether LEDs will really fulfill their long life expectancy remains to be seen - even the 35,000 hour ones would need to be left on 24x7 for 4 years before they come close to reaching their advertised range. And LED lights do dim with age - so while a bulb might have a lifetime of 35,000 hours, that doesn't mean it will emit its starting light level for the full 35,000 hours - the older it gets, the less light it will emit. LED lights do slowly fade in brightness and therefore in efficiency, although they will remain more efficient than either CFLs or incandescent bulbs throughout their life.
The "color temperature" of a light, measured in 'degrees Kelvin', determines how we respond to its light. Most people are used to the yellowish glow of incandescents at around 2800 Kelvin (2800K), even though fluorescent lights are closer to the natural daylight temperature of 6000K. Any LED house light with a color temperature of 6000K or higher will seem to appear bluish, and any LED house light with a color temperature over about 4000K will appear whiter than an incandescent.
While people are typically worried about how fluorescent or LED lights can make their rooms look hospital- white instead of the comforting yellow hue given off by incandescent lamps, remember that a little compromise on color temperature will really help reduce your energy bill. Be a trend-setter, not a trend-follower - start converting your lights to true daylight colors, whether with fluorescent lights or LED house lights. You will make it easier for your neighbors to switch over, when they find out they won't be the first people with a slightly bluer light tinge in their homes.
Whether you switch some of your lights to LED lights now, or wait for the technology and reliability to improve, you can be sure that LEDs will play a bigger part in lighting our houses in the years ahead. In my opinion it makes sense to wait, except in certain special lighting situations where the highly directed, focused light of LEDs is what you want, and where you have money to spare. If you just want to save money - or to cut your energy use for environmental reasons - the same amount of money spent on weather-stripping, or most other energy efficiency upgrades, will reduce your energy bills and CO2 emissions more than buying today's LED lights.
Robin Green runs Green-Energy-Efficient-Homes.com, a website that helps people save energy in their homes. For more on energy efficient LED lights, see LED house lights on Green Energy Efficient Homes.
