I personally have a thing for good lighting, and perhaps it's my theatrical lighting background. The warm amber glow of a tungsten filament bulb is something that a CFL has failed to match, much to my dismay. CFLs just don't have the coziness factor to me, and I dislike their cold industrial color temperature; it irks me. Yet I've purchased and used them anyhow because the reduced power consumption and resultant savings appealed to me despite the ugly-factor.
But recently, I've noticed more and more LED bulbs on the shelves, and I'm encouraged by everything I'm seeing. I've even tried some out, and I'm super happy with the look of them in my home. Specifically, I'm referring to the Cree 9.5 watt (60-watt equivalent) warm white LED bulbs being sold at Home Depot:
http://www.homedepot.com/p/Cree-9-5-Watt-60W-A19-Warm-White-2700K-Dimmable-LED-Light-Bulb-1-Pack-BA19-08027OMF-12DE26-1U110/203991774#.Uj2rWcZQGm5I've bought several of these, and I love them! The cost ($12.97 ea.), the light quality is much closer to that of an incandescent, and the effect on the power bill has been wonderful.
But it got me to thinking, and wondering, about the point at which you begin to save money on using this type of bulb, and how does it compare to it's fellow bulbs, like a 60-watt equivalent CFL and a 60-watt incandescent. Sometimes it's just nice to see the numbers.
I just put together a spreadsheet comparing incandescent, CFLs and LEDs on initial cost, power consumption costs, and lifespan. I took a sampling of bulbs and their specs off the HD website. This is assuming all 60-watt equivalent bulbs, 3 hours of daily use, 365 days a year, at $.13/kWh.
Here are my findings:
An incandescent costs about $.66, uses 60 watts, and has a lifespan of 2000 hours. Used 3 hours/day, 365 days per year, the cost of using this bulb is $8.54, and with the use listed above it will last about 1.8 years, so you'll be replacing it often. In that 1.8 years the purchase of the bulb + operation will have cost you $16.26. And just for further fun, if you were to use this type of bulb over 30 years, and assuming the cost of power never goes up, this bulb will cost you $256.23 to operate...$267.45 if you include all 16 bulbs you had to buy at the store since this bulb burns out so often.
A CFL costs about $5.49 (HD brand from a 2-pack), uses 14 watts, and has a lifespan of 10,000 hours. Used 3 hours/day, 365 days per year, the cost of using this bulb is $1.99, and with the use listed above it will last about 9.1 years*. In that 9.1 years the purchase of the bulb + operation will have cost you $23.69. Over 30 years, you will use 4 bulbs, and will have paid a grand total of $81.75 to buy and use this type of bulb.
* caveat to the lifespan - The life of a CFL is affected more by the number of times it is turned on, and less the number of hours it is burning. If you use CFLs in your bathroom, where you turn the lights on and off for brief moments, you're shortening the life of the bulb. This could be your problem if they aren't lasting, and perhaps you need to use LEDs or incandecents in areas where lamps are lit less than 3 hours. See this link for further explanation:
http://www.houselogic.com/blog/lighting/cfls-light-bulbs/An LED (Cree brand from HD) costs about @12.97, uses 9.5 watts, and has a lifespan of 25,000 hours. Used 3 hours/day, 365 days per year, the cost of using this bulb is $1.35, and with the use listed above it will last about 22.8 years. In that 22.8 years the purchase of the bulb + operation will have cost you $43.85. Over 30 years, you will use 2 bulbs, and will have paid a grand total of $66.51 to buy and use this type of bulb.
I know MMM has already thrown out numbers on ROI, but that was awhile ago, before the Cree bulbs showed up in stores at their awesome price. The prices keep coming down, and they are now more in the consumer's favor. Plus they just plain look better than CFLs.
The breakout point for LEDs to begin surpassing CFLs in savings happens at the 12 year mark (which is good, since the LEDs are advertised to last 22.8 years). The longer you commit to a bulb, and the longer you use it per day, the more the savings (or costs) compound. Over a span 50 years, if you just used a 60 watt incandescent FOR ONE LAMP, you would have bought 28 bulbs and spent $445.53!! For the same length of time, if you used the comparably watt'd LED bulb, you would have bought 3 bulbs, and spent $106.53, a savings of $339 to just light up one lamp.
There's an added environmental benefit beyond reduced power consumption: LEDs don't contain any of that pesky mercury that's in CFLs, and with the longer lifespans, that means bulbs are replaced less often, which means fewer bulbs tossed into landfills.
I've attached my spreadsheet. You can adjust the cells in yellow: average daily use, # of days used, cost per kWh, and #of years to see how the adjustments compare. Eventually I hope to add to this halogen-type bulbs and their equivalents for more cost comparisons.