My neighbor Will, an engineering type who loves numbers, decided to switch out all the lights in his house to LEDs. In his enthusiasm, he created this incredible spreadsheet analyzing the Great Changeout and comparing wattage and other aspects. The thing is fairly elaborate, so I’m going to upload it as an Excel file:
The file has two spreadsheets, so check out the tabs at the bottom when you open it.
Will says he figures his utility-bill savings are about $25 to $30 a month. I asked him how he came to that conclusion — by comparing power bills, or by calculating energy use based on the lights’ wattage — and whatever got into him to engage this potentially pricey project. Here’s what he says:
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Savings are based on watts consumed compared from beginning 2008 until now. The average is $30 a month, with the change of bulbs and Levelor black-out blinds on the sunny side of the house.
Actually I started incandescent, then went to CFL (Compact Florescent Lights), and am still moving to L.E.D. bulbs as I find ones cheap enough and that fit my purpose both in color and fixture.
Flickering: Incandescent bulbs flash on and off at a rate of 60 times a second. CFLs flicker like the charged gas they have inside. But L.E.D. bulbs are constant narrow-band light…no flicker….no UV, no attracting bugs,
The cost per bulb is listed on the sources tab of my sheet, as well as where to get them. I try to keep to around $19 to $25 a bulb.
I have been changing them out a chunk at a time. I plan to do the rest of the PAR 30 lamps this year.
In the candela type bulb, I have only been able to find a good CFL equivalent. So far none of the L.E.D. versions have met my specifications.
The original 60-watt incandescent were cooking my fan lights. So they got changed to CFLs right away, to prevent a fire hazard.
I did the spread sheet because about ten people were asking for the information and I found myself rewriting it over and over. I figured I’d do this spreadsheet to save me the time. Since I was already doing the research for myself I figured I’d share and save others the hassle of figuring out all the engineering crap you have to wade through in order to understand these.
It seems many L.E.D. bulb manufacturers want you to pay for all their engineering, so the bulb is like a hundred bucks. And they wonder why no one wants to buy it.
It sort of like those stereo speaker ads from the 70s and 80s. “Big sale! Pair of 200 Watt speakers for $49.99!” But the problem was it was a big lie. They were actually thinking 100 watts per speaker, that being maximum peak power rating, so after you calculated the RMS value, they were actually 50-watts speaker. With today’s L.E.D. bulbs you CAN NEVER GO BY THE INCANDESCENT EQUIVALENT ON THE PACKAGE…they are either lying or don’t know their product. 🙂
If I replace the rest of the bulbs to L.E.D, I will have gone from over 3000 watts usage to below 700 watts, and that’s just in bulbs. I may use LightKiwi BR30 bulbs for outside motion safety lights. I’m currently using 75-watt incandescents, but these LightKiwi bulbs are only 11 Watts each. $24 from manufacturer’s web page or when on sale at Newegg .
Now if I can just get the hamsters to power the a/c in the summer I’ve got it made. 😉
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You can see what other mischief Will has been up to by going to his central website and exploring from there.
Incandescent bulb: Gluehlampe. KMJ, alpha masking by Edokter. Creative Commons Attribution-Share Alike 3.0 Unported license.
LEDs: Commercially available LED lamps (“light bulbs”) with Edison (screw-type) base. Geoffrey.landis at en.wikipedia. Creative Commons Attribution 3.0 Unported license.