LED Lighting

A light emitting diode, or LED, is light source that is generated by electrons passing through a semiconductor material.
Credit: GE

LEDs are a type of solid state lighting that is more efficient than most incandescent or fluorescent lighting because it emits light in a specific direction without a great deal of heat loss.

LEDs vs. CFLs

Compact fluorescent light bulbs, or CFLs, last about 8 to 15 times longer than incandescent bulbs, which have a life of between 1000 and 2000 hours (or 42 to 84 days, if on for 24 hours a day). ENERGY STAR, the Environmental Protection Agency’s program for rating energy efficient appliances, requires that their labeled CFLs have a life of at least 6,000 hours, though many exceed this requirement. In fact, the average lifetime for an ENERGY STAR labeled CFL is 10,000 hours.

In comparison, LEDs last between 25,000 and 100,000 hours. ENERGY STAR rated models have lifetimes that are 35-50 times longer than incandescents and 2-5 longer than CFLs.

Despite the fact that LEDs last much longer than CFLs, they are less popular than their counterparts. Consumer Reports released a study in August 2012, which found that while 90% of Americans have replaced their incandescent lighting with more efficient bulbs, such as CFLs and LEDs, almost 75% of consumers have purchased CFLs.

In another lighting study, Precision Paragon found that in 2012, 10.3% of lighting professionals believed they would mostly use LEDs for lighting retrofits, while 84.3% thought they would mostly use linear fluorescent bulbs.

CFLs are more popular than LEDs because of the lower cost. According to Consumer Reports, high quality CFLs cost $1.25-18, while LEDs cost $25-60. While LEDs cost more upfront, they actually save more money over their lifetime, though - a CFL saves about $60 during its life, while an LED will save $130. Even the cheapest $25 LED lasts 75% longer than an incandescent bulb.

This scenario will most likely change in coming years, as LEDs are expected to drop in cost over the next decade. A study from Pike Research estimates that LEDs will replace 52% of the global market for lighting in commercial buildings by 2021, due to lower prices and increased efficiency.

Payback Period of an LED

When replacing your lightbulb with an LED, an important metric for measuring the benefits is the length of the payback period. The shorter the payback period, the sooner you will see the financial benefits of your investment. The payback period of an LED retrofit will depend on the price of electricity in your area and the cost of the LED. If either of these are high, it will increase the payback period.

Let’s try a sample payback period calculation. Say you’re replacing a conventional 60 W incandescent light bulb with an ENERGY STAR rated LED - the Philips EnduraLED 12.5 W. Since 12.5 W is about 20% of 60 W, the EnduraLED is about 80% more efficient than the incandescent.

Say you use the incandescent light bulb for 5 hours per day. It will use 300 Watt-hours per day (60 W x 5). Over the course of 365 days (or one year), it will use 109,500 Watt-hours per year. Divided by 1,000, this is 109.5 kilowatt hours (kWh) per year.

If the electricity in your area costs $0.10 per kWh, then the incandescent bulb costs $10.95 to run annually (at 5 hours per day).

Philips’ LED uses 80% less power, so it would cost about 80% less to run at the same rate for a year. At 12.5 W, it will use 62.5 Watt-hours per day, if left on for 5 hours (12.5 X 5). Over the course of one year (365 days), it will use 22,812.5 Watt-hours, or 22.8 kWh. This means it will cost $2.28 per year to run the LED for 5 hours per day.

This amounts to a savings of $8.67 per year.

The Phillips EnduraLED costs about $30 on Amazon. At a savings of $8.67 per year, it would take about 3.5 years for the LED to pay for itself (if it were used for 5 hours per day). The product lasts about 25,000 hours, or about 13.7 years if it were used for 5 hours a day. So, the LED would survive the payback period by over 10 years.

Free LEED Exam PreperationENERGY STAR LEDs

ENERGY STAR LED lights have passed a variety of tests that demonstrate that they save money and meet certain standards for quality and durability. Therefore, it's a good choice to look for lighting with this label when shopping for LEDs.

According to ENERGY STAR, their qualified LED lighting meets certain standards, such as:
- A minimum of a 3 year warranty
- Use 75% less energy than incandescent counterparts
- Last 35-50 times longer than incandescent lighting and about 2-5 times longer than fluorescent lighting
- Comes on instantly when turned on
- Don't flicker when dimmed

See ENERGY STAR’s complete list of criteria for qualifying LEDs for residential applications.

How to Choose an LED

Consumer Reports issued a list of 4 ways to avoid common LED lighting problems:

1. Purchase LEDs with higher lumens to prevent dim bulbs. For example, replace a traditional 60 W incandescent with an LED with a minimum of 800 lumens.

2. The higher the Kelvin number (K), the cooler the light. The warm light from a traditional incandescent is about 2700 K, so you can replicate the warmth with an LED of around the same number.

3. LEDs with higher CRI will prevent unflattering lighting.

4. Make sure the light works with the fixture you’re using, because otherwise it may burn out early. If it does stop working before anticipated, bring it back to the retailer or manufacturer.

How to Recycle LEDs

Once you are finished using your LED, you should dispose of them in an environmentally friendly way, if possible. Over 95% of an LED is recyclable, and they do not contain mercury, making them easier to safely recycle than CFLs. While LEDs are recyclable, it is not a typically a curbside-pickup item (though it may be), so you may have to search for the best place to drop off your used lightbulbs.

The first step is to call your local recycling center and ask them how to recycle your LEDs. It may be a curbside pickup item or the center may have a specific drop-off location or bin for them.

If your local recycling center does not accept them, you can try recycling them through private companies. Some LED manufacturers or vendors will take them back after use for recycling. If this isn’t the case, both IKEA and Home Depot have drop-off locations for LEDs. Check your local store to see if they have a recycling program.

Earth911's website is very helpful for finding where and how to recycle many kinds of materials. Type “light bulbs” into the search box with your location, and you will find the nearest places to recycle your LEDs (and other waste).


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