How long does it take for energy-bill savings to cover the purchase cost of LEDs?

The amount of time it takes for LEDs’ reduced energy consumption to save you enough to cover their cost depends on how many hours a day your lights are on, the current cost of electricity in your area and the wattage of the lights in your home. As an example, consider a two-bedroom home with roughly 50 bulbs that consume an average of 70 watts per bulb and produce a total of 50,000 lumens of light, in a region where electricity costs 12 cents per kilowatt-hour. If you replace all those with LEDs, including ceiling bulbs, under cabinet lights, and everything in between to produce the same lumen output, the LEDs themselves would cost about $3,500. But the new LED lighting would only consume a little more than 800 watts instead of the 3,500 used by the incandescents.

At this rate, having all the lights on costs about 32 cents less per hour. At this savings rage, the lights will pay for themselves in savings in 11,000 hours, which is just under 4 years at eight hours a day of usage. Incandescents burn out after 1,000 to 2,000 hours on average, so you would have to replace your incandescent lights a minimum of five times in that period. That extra time and cost is also relevant. Remember that using more lights, more expensive electricity, or keeping lights on for longer shortens the payback time.