Between Incandescents, CFLs, and LEDs, there are many different lighting options available for the homeowner. The problem is that there are so many options, the energy-saving technology keeps improving, and costs keep adjusting. I've done a cost comparison between incandescents and CFLs that showed how much better an investment CFLs were. Since then, a few models of LEDs are available for the home and I have now included them in a cost comparison.
Until someone proves me wrong, I'm convinced the spreadsheet below is one of the best lighting cost comparisons on the web. I've put in some reference data for each bulb so you can verify the data. For the incandescent, I included a GE long-life 60-watt bulb. I'm using the n:vision CFL's I use in my house which are still working flawlessly and out of probably 15 bulbs I haven't had 1 failure in 1.5 years. Finally, for the LED I'm comparing the newly released Pharox60, 6 watt dimmable LED by Lemnis Lighting and Digital Light. Update - 2/10/11 - I've updated the sheet with more recent data. Home Depot changed the n:vision brand name to EcoSmart. I'm using EcoSmart bulbs for both CFL and LED because I can easily get them at Home Depot and I've been happy with the quality so far. The EcoSmart A19 LED I'm testing out is about 30% cheaper than the Pharox60 LED and has a higher light output.
The cells in yellow are meant to be edited by you based on your situation. The cells in green are current prices for the lights I'm comparing in the sheets. If you find better prices or want to compare different lights, adjust these prices accordingly.
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The first thing to notice is the Lumens (light output) of each bulb. The CFL uses less energy than the incandescent, but puts out more light! And while the LED uses less energy than the other bulbs, it puts out 2.5 times less light than the CFLs! According to my sheets, it would take almost 30 Years before a current investment in an LED bulb would turn out to be the better investment over a CFL. Now, that's based on an electricity price of $.010/kWh, and if you pay more than that, LEDs look a little more attractive.
Since LEDs have such a high initial cost, it is very hard to re-coup that cost over the life of the bulb. The other issue is how much less light they put out compared to the incandescent or CFL. What I will say is that if you are reluctant to adopt CFLs in your house due to concerns over mercury (even though it is a very minuscule), then the LEDs could be a great alternative to incandescents. Since incandescents use so much electricity (most of the energy that goes into them turns into heat), the payback of an LED at .10 cents per kWh is around 5 years when compared to the incandescent.
The important thing to take away from the sheet is how bad a monetary investment incandescents are and how much energy they use compared to CFL and LED technologies. It's time to get away from 100 year old energy-wasting technology and start saving your home money and helping to waste less energy!