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Saw an article on the net or news, and family put up 25,000 LED lights outside--and claimed it only cost $15 in electricity for the whole season---I call B.S.
Actually, depending on the variables (how many days is a 'season'?, how many hours a day? how much do they pay for electricity?), it could be ball-parkish right.
25,000 LEDs would be 500 strings of 50 each. My 50 string LEDs are using ~ 3.5 watts. 500 * 3.5W = 1750 watts total (1.75 kW). At the national average of ~ $0.11 per kWh, that's $0.19 per hour.
So $15 would pay for 78 hours of lighting. 13 days @ 6 hours per day would do it. 19 days @ 4 hours/day, etc.
They may pay less per kWh, but even so, not so far off to call 'BS' I'd say. And if they have 'blinkers', those are off part of the time, and no in-rush current with LEDs.
What attracts me to them is the electricity savings.
I don't have a set, but I'm just being lazy as I put up the old set, so I have not bought LED replacements.
I figure we use $10 extra per month for Christmas lights, so with easily 1/5 the cost, the LED's should save us $8/mo paying for themselves in 1 to 2 seasons.
I'd like to see your math. Or are you comparing to the really old-style 'night light' sized bulbs that are 6 watts each? I'm assuming people compare the LEDs to the mini-lights?
For me, the small electricity savings is a plus, but the (hoped for, and so far delivered) reliability is the key. Too much time spent replacing bulbs, trying to get strings to work, and then throwing several sets out each year, even after my attempts at repair (and I strip down the 100 light strings to make a 50 string with the half that does light).
By my calcs and estimates, with $0.11 kWh, 5 weeks at 8 hours per day, it would take about 20 strings to save $8.00. I'm paying ~ $5 for LED strings, I haven't price checked, but I'd guess the mini-light filament style are $2? The $60 delta would take a long time to pay back in electricity savings. But I think I'll see payback in durability. Less fiddling is something I'd pay for, replacing those little bulbs is tedious.
-ERD50