View Single Post
Old 01-18-15, 05:53 PM   #9
Apprentice EcoRenovator
Join Date: Sep 2008
Posts: 116
Thanks: 29
Thanked 12 Times in 11 Posts

My guesstimate is something like 15 years at 10c/kWh, or less if you pay more for electricity. Lets say the 10" tubular skylight provides ~3000 lumens (Site says <4k max) that you would otherwise generate from 3 ~1000 lumen LED cans at 15W each for 6 hours/day.

45W*6hr/day*365day/year=~98,000Wh/year, so ~100kWh/year. 100kwh/year at 10c/kWh is $10/year, so ~15 year payback assuming DIY install. Obviously if you're never home in the day or only in the kitchen for a couple hours per day, that changes the economics a bunch. On the flip side, if you're in a high tier in CA, then it could be a payoff in less than a decade.

Edit - I forgot to include the cost of the LED cans, which would be ~$35-$55 depending on whether or not you got them on sale.

Last edited by roflwaffle; 01-19-15 at 11:48 AM..
roflwaffle is offline   Reply With Quote