January
1 - 2008

Eco-quandary: New year, new lights?

LEDHappy New Year!

I’m starting 2008 with a couple of money-saving ideas.

Today, I’ve been researching LED lights for our basement. Our home has a nicely refinished basement, courtesy of previous owners. But when it comes to energy efficiency, it’s a big sink — it features 12 can lights in the ceiling of the family room, hallway and bathroom. Each of these recessed light fixtures contains a 75-watt bulb.

Currently, our basement sucks up a total of 900 watts of electricity every hour all the lights are on. I estimate these lights glow an average of three hours a day (some of them are on frequently through the day), and at a cost of about $0.11 per kilowatt hour, that totals about $0.29 per day or $8.76 per month.

At this Web site, which sells LED bulbs, they offer LED floodlights that use 4 watts of electricity. However, to replace all 12 bulbs in my basement would cost at least $300. That’s a lot of money for light bulbs. Is it worth it?

  1. If we replaced all the lights with 4-watt LEDs, we would instead use 48 watts — a 95% reduction. The cost would be less than $0.02 per day or about $0.47 per month. The annual savings after the switch would be almost $100. The new bulbs would pay for themselves in 3 years.If you consider that LED bulbs have an estimated life of about 25 years (30,000 hours), while incandescent bulbs have a life of 1 to 2 years (1,500 hours), you’ll realize that we would have to replace significantly more incandescent bulbs. If we use a more conservative lifespan for LEDs of 20 years, we would need to replace about 10 sets of incandescent bulbs during that time. Each bulb costs about $5, or $60 for the whole set. Ten changes of bulbs would cost $600, assuming prices of the bulbs do not change in the next 20 years.

    Over a 20-year time frame, the LED bulbs would save $1,700 in energy costs ($100 per year x 20 years – $300 cost of purchasing the bulbs), again assuming costs do not change, and $600 in bulbs not purchased, for a total 20-year savings of $2,300. Additionally, during that time, we can prevent 60 bulbs from entering the waste stream.

    However, these bulbs provide 130 lumens – a measure of light output. A 75-watt incandescent bulb, by the definition on that link, produces more than 1,000 lumens, so we would pay the price in dimness.

  2. Then again, on a site like this one, I could buy a combination of dimmable/non-dimmable compact fluorescent lights (CFLs) for the various dimmable/non-dimmable sockets. The purchase would be about $150 for 12 bulbs, with a life of 8,000 hours or 7 years. The bulbs use about 15 watts to produce about 700 lumens, which might be acceptable given how many lights we have downstairs. We would save $7 a month, or $84 a year, in energy costs. The bulbs would pay for themselves in less than 2 years. In addition, we would save at least a couple of changes of bulbs during the lights’ lifespan. Over that lifespan, the bulbs would save about $438 ($84 in energy savings x 7 years – $150 purchase price). To compare to the LED example above, in three lifespans (21 years), these bulbs would save $1,314 ($438 x 3). Not as impressive as the LEDs, yet still notable.

I would like to have more information about the quality of light from these LEDs. I noticed that our LED Christmas lights this year were *extremely* bright – much brighter than traditional Christmas lights, so I wonder if the lumen info is correct.

What do you think? Does anyone have experience with LEDs or CFLs in a recessed can light fixture?

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