| -- End Ad Box ---> | | | | the end of it’s lifetime. However, the lifetime of |
| Green is good, and right now, energy efficient lighting is | | | | a bulb does not mean it is unusable, only that it’s |
| all the rage. With the looming phase-out of | | | | light output has degraded to a certain point. The LED |
| old-fashioned incandescent light bulbs in many | | | | bulb may continue to be useful for several thousand |
| developed countries, people are faced with choosing | | | | hours past it’s stated lifetime. Unlike |
| between a handful energy efficient forms of lighting | | | | old-fashioned light bulbs, it is extremely rare for an LED |
| — compact fluorescents (CFL) and light emitting | | | | light to simply burn out. Rather, it will gradually fade |
| diodes (LED). This article will help you make good | | | | over time. |
| decisions when buying residential LED light bulbs. | | | | Color |
| CFLs are good for now, but
| | | | As a general rule, you should use warmer light indoors, |
| You have likely already adopted energy efficient | | | | and whiter light outdoors. A color temperature of |
| compact fluorescents (CFL) as part of your effort to | | | | 2500-4000 Kelvin works great indoors. You should use |
| reduce your carbon footprint. While CFLs are energy | | | | a bulb with a color temperature of 5000-7000 Kelvin |
| efficient, they have drawbacks such as mercury and | | | | outdoors, as the whiter light allows your eyes to see |
| relatively short lifespan. Also, CFLs are not available in | | | | better at night. |
| sizes that replace track light bulbs, such as MR16 and | | | | White light in the 5000-7000 Kelvin range is also |
| GU10. It is unlikely that CFLs will be available in these | | | | excellent for display cases, boutiques, artwork, or other |
| sizes. | | | | settings where you need excellent color rendition. |
| CFLs have made giant inroads over the last couple of | | | | Type of LED lamp |
| years. The low cost and high energy efficiency of | | | | LED light bulbs use one or more tiny semiconductor |
| CFLs have made them favorites with people replacing | | | | lamps to produce very focused light. Contrast this with |
| incandescent lights. According to the Energy | | | | normal light bulbs that generate light in all directions. LED |
| Information Administration, a government agency, 9% | | | | lamps are currently available in two forms: traditional |
| of a household’s energy costs are related to | | | | LEDs (typically 5mm), which are smaller, and high |
| lighting. People are genuinely concerned with lowering | | | | power LEDs. Light bulbs using traditional LEDs require a |
| their energy consumption, and lighting is one of the | | | | large number of LED lamps to produce sufficient light, |
| easiest things a person can improve on. With | | | | whereas high power LED bulbs use one or more |
| worldwide support from mass-market retailers, | | | | lamps to generate light. |
| governments, and citizens, energy efficient lighting is | | | | In general, the more LEDs, the better the light |
| seeing a new dawn. While CFLs provide a good | | | | dispersion. Always get LED bulbs with more than one |
| combination of efficiency and cost, there is an even | | | | LED. You will find that single LED bulbs produce a very |
| better option on the horizon — LED light bulbs. | | | | conspicuous outline, similar to a halo. Unless you enjoy |
| Introducing the next generation of ultra energy efficient | | | | halos across your walls, it’s better to buy light |
| light bulbs — LEDs | | | | bulbs with multiple LEDs. |
| LED light bulbs are semiconductors, just like the chips in | | | | Here are some common track light and flood light bulb |
| your computer. These semiconductors emit energy in | | | | types, and suggestions for the LED arrangements: |
| the form of photons of light. LEDs have come a very | | | | For track bulbs such as MR-type and GU-type, try to |
| long way since they were invented in the 1960s. You | | | | get bulbs with 3 high power LED lamps (preferably |
| have seen LED lamps for decades in the form of | | | | using CREE or Nichia lamps). Avoid buying track bulbs |
| indicator lights on electronic products. Now, these LED | | | | using an array of traditional LED lamps, as these are |
| lamps light bulbs have evolved to the point produce | | | | not as effective as high power lamps. |
| enough light for household and commercial applications. | | | | For flood light bulbs, such as PAR-type, you can find |
| LEDs are extremely energy efficient, and have | | | | reasonably priced traditional LED arrangements. |
| lifetimes ranging from 50,000 hours to 100,000 hours. | | | | High-power LED flood lights produce good light, but are |
| LED light bulbs are the perfect complement to your | | | | also very expensive. In my experience, a PAR bulb |
| collection energy efficient lighting products. | | | | using 120 or more traditional LED lamps works just as |
| Tips for Buying LEDs | | | | good, at a fraction of the price. |
| There are several varieties of residential LED light | | | | Cost and energy savings |
| bulbs on the market. Presently, LEDs best replace | | | | LED bulbs have a higher upfront cost, but they pay for |
| track lighting and flood lights, both of which take | | | | themselves several times over their lifetime. Because |
| advantage of the directional nature of LED light. Below | | | | LEDs have lower power consumption and a very long |
| are some tips for buying LED light bulbs. | | | | lifetime, they are very energy efficient. Let’s |
| The Basics | | | | take an example of a $45, 5-watt, 50,000 hour MR16 |
| You want to find an LED bulb that produces a healthy | | | | LED bulb. Let’s assume a constant electricity |
| amount of light, but at the lowest possible power | | | | cost of $0.10 per kilowatt hour, and a 0.61 electrical grid |
| consumption. A good metric that equalizes your | | | | CO2 output factor. Compared with a similar $8, |
| search is lumens per watt. To derive this figure, | | | | 25-watt halogen MR16 bulb, the LED will save $255 |
| simply divide the bulb’s number of watts into the | | | | and reduce carbon emissions by 1,345 pounds. Not bad |
| number of lumens. Right now, a good LED bulb should | | | | for a light bulb. |
| have at least 40 lumens per watt, but preferably more. | | | | As energy costs continue to rise, the cost savings and |
| The question is often asked about comparisons | | | | carbon reduction from using LEDs will become far |
| between normal light bulbs and LEDs. Here are some | | | | more pronounced. |
| examples to guide you: | | | | Buyer beware — LEDs cannot replace general |
| 5-watt, 3 high power CREE LED, MR16 ~ 25-watt | | | | illumination bulbs (yet) |
| MR16 Halogen | | | | Right now, there are plenty of options for LED light |
| 5-watt, 3 high power CREE LED, E27 spot ~ 30-watt | | | | bulbs. And that’s a bit of a problem. Several |
| E27 spot Halogen | | | | sellers of LED bulbs claim their bulbs are powerful |
| 6-watt, 165 traditional LEDs, PAR38, ~ 50-watt PAR38 | | | | enough to replace general illumination bulbs such as |
| incandescent | | | | incandescent and CFL. This is simply untrue. Many of |
| Lifetime of Bulb | | | | these replacement bulbs cost nearly $100 and |
| Many manufacturers of LED bulbs claim lifetimes of | | | | use over 10 watts of power. You are much better off |
| 50,000 hours to 100,000 hours. The lifetime of an LED | | | | using a $3.00, 10-watt CFL for now. However, keep an |
| lamp is generally considered to be the point where the | | | | eye out for LED general illumination bulbs over the next |
| light output has declined to 70% of it’s initial | | | | few years, as they will become very competitive with |
| output, measured in lumens. So, a 300 lumen LED bulb | | | | normal light bulbs. |
| with a lifespan of 50,000 hours will have 210 lumens at | | | | |