New Lights in Old Fixtures

Philips Lighting has a line of LED lights called EnduraLEDs that replace incandescent bulbs and compact fluorescent lamps.  The model A19 also won the U.S. Department of Energy’s L Prize for innovative energy-saving lamps and is ENERGY STAR® labeled.

Long life (25,000 hours), the A19 produces the same amount of light as a 60-watt incandescent (“standard”) light bulb, drawing 12.5 watts of power.   It offers three advantages over compact fluorescent lamps (1) the “color” of the LED is warmer than CFL’s; (2) the LED lamp is dimmable; (3) the LED lamp has no mercury.   (EPA calculations indicate that the savings in mercury spewed into the air by fossil-fuel power plants when replacing an incandescent lamp with a CFL is more than the mercury in the CFL itself, however.)

Sounds great, is there a downside?  Price tag.   The on-line price for the A19 is about $33.  The on-line price of a 60-watt equivalent General Electric CFL is $1.50, with claimed 8000 hour life, 13 watts.

The old-fashioned incandescent 60 watt bulb has an even lower purchase price, at $.55 for a Sylvania lamp, with claimed life of 1875 hours.

Let’s review the arithmetic for energy costs:

Power in watts x hours of use = watt-hours.   Divide by 1000 to get the unit kilowatt-hours (kWh) that your utility sells you.

Multiply the kilowatt-hours by the unit price.

Example:   60 watt lamp x 100 hours x $0.10/kWh = 6000 watt-hours x $0.10/kWh = $0.60.

Here in the upper Midwest portion of the United States, we also have to throw in about 12 pounds of CO2 emitted into the atmosphere to generate the 6 kWh to run that light bulb.   No dollar cost yet on the CO2 but some day the bill will come due.

Using the arithmetic we just reviewed, we can make a table to compare the three lamps.

The CFL and LED lamps are clear winners in terms of energy use and total cost of use over 25,000 hours, which is about 3 years, 24 hours a day.   On the other hand, if lamps are used just a few hours a day, it will take many years to get to 25,000 hours of use.

Still, these new LED lamps are a strong competitor to CFL’s and incandescents in any application that requires dimmable lamps, has the lights on many hours a day and requires long-life to reduce the effort to replace lamps.    Retail stores and restaurants may be able to make a narrow economic argument in favor of LEDs right now even if they are not counting the carbon impact of replacing dimmable incandescent lamps with the energy sipping LEDs.

Generally, the price tag of the LEDs will come down over time. Even at the price today, when I look at the economic, environmental and aesthetic factors all together, the LED lamps are looking attractive.   I’m going to get some to try.  How about you?





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