Thursday, February 12, 2009

LED, CFL or Incandescent? Ask Pablo

LED lights | Salon Life
A 10W CFL, available online for $6.90, has an expected median lifetime of 10,000 hours. While this is about 10 times longer than the life expectancy of an incandescent bulb, it is only one-fifth the expected life of the LED. So LEDs have the potential of cutting down on ladder time by a factor of 50 over incandescent bulbs! At about 25 cents apiece, the incandescent has by far the lowest upfront cost, which is why many people still use them. If we normalize the cost of all the bulbs over a 50,000-hour period, the incandescent bulbs cost $12.50, while CFL bulbs cost $34.50, and the LED bulb costs $59.95. But, as you may already know, the upfront cost of a bulb is by far the cheapest part. It's the electricity required to operate the bulb that adds up.

Over a period of 50,000 hours, a 40W incandescent bulb will use 2,000 kilowatt-hours (kWh). At 15 cents per kWh, this will put $300 in the pocket of your local utility, bringing the total cost of the incandescent bulb, over 50,000 hours, up to $312.50. The CFL bulb only uses 500kWh over the same time period, or $75, totaling $109.50. Finally, the LED bulb will use 350kWh for $52.50, with a total cost of $112.45. So, in this example, the LED light does cost a few dollars more but the difference is negligible. Think of the time you will save by not running to the store to buy bulbs and climbing the ladder to change them.

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