Quote:
Originally Posted by wifi
Hmmmm, lets review that again. (60-11)/60*.0007 is the savings per hour of using an 11 watt LED vs a 60 watt incandescent. Payback of the LED would be 10.95/( (60-11)/60*.0007 ) = 19155 hours or 798 days or
2 years+10 weeks.
This is assuming NB leaves his light on 24 hrs/day and does not include the added savings of replacing blowing incandescents.
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Right, however very few people leave their lights on 24/7. 5 hours/day is a somewhat high average.
10 years = 3650 days. 3650 days * 5hours/day = 18,250 hours of operation over 10 years.
The replacement cost is harder to factor. The LED bulb *should* last that entire time, though you'll be approaching the point where its light output is probably starting to fade noticeably.
An incandescent bulb lasts about 1500 hours, so you'll be on your 12th bulb by that point, having spent about $8 on bulbs, depending on how/where you buy them. That could put the breakeven point closer to 5 years.
In either case, don't buy LED bulbs for anticipated cost savings...