FREDWESTON.NET - The Bogus Math of LED Christmas Lights
The Bogus Math of LED Christmas Lights
Posted under Miscellaneous on Monday, December 2, 2013 @ 10:48:12 PM
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this is my house all decorated for xmas.

for the past few years i've only put lights along the roofline, and maybe a few in the one tree to the right of the garage, but this year i guess i was more in the holiday spirit and decided to put a few more up.  christmas lights are a pet peeve of mine.  not being completely clueless, i realize that most of the lights on store shelves are made in china by the lowest bidder.  furthermore, christmas lights are about the simplest thing to assemble, so i feel like manufacturers are banking on that holiday spirit compelling folks to spend more than they should on their lights.  being a cheap bastard, i always comparison shop for anything i'm going to spend more than $50 on (unless there's a differentiating factor, which for christmas lights there is not).  while i was looking around online to determine who had the best lighting deals i came to the conclusion that most folks will look around for a minute or two and throw whatever the best option they found in that span of time was in their cart and call it a day.  i checked four different big box stores (home depot, lowes, walmart and target).  normally i don't like to frequent walmart because spending time around the clientele that tends to inhabit their stores is less than desirable - i'm talking about you, 350lb woman in spandex pants yapping on your cell phone the entire time you're in the store.

i'm getting off track here.  so i checked the websites and limited my search criteria to plain-jane 20 foot outdoor multi-color christmas lights, nothing fancy.  i found about 100 different options and 99 of them were $7.50 or more.  so that takes me back to my theory about retailers hoping you'll give up after a few minutes and spend more money when you don't need to.  in this case it turned out home depot had the best price at $1.98 per string/box.  off to home depot i go and return home with 20 boxes of lights.

now that we're four paragraphs in, i can finally tell you what my real gripe is.  everyone seems to want led lights and i'm convinced this is simply because that's what retailers choose to focus on in their advertising; and why not?  i'm sure margins on led are much better than they are on incandescent lights.  certainly led is more efficient as well, which cuts the cost of powering all those lights by 10x.  who wouldn't want that?  well, in short, probably anyone that bothers to do some basic math.

based on the price difference between incandescent and led and my vague knowledge of what i pay for electricity, i knew there was no payoff before doing the math, but i was bored and decided to see just what the numbers looked like.

i based my numbers on my situation.  i have an average sized house and i think i probably put up an average amount of lights, or maybe slightly more than average considering the number of houses in my neighborhood that have zero holiday spirit and match that with the number of lights they put up.

here's some data that will help you understand the following if you have interest in doing so:
  • 14 strings of lights
  • the incandescent power draw of these lights is 583 watts (i measured this with my kill-a-watt)
  • based on data i found online, i extrapolated that an equivalent amount of led lights would draw only 63 watts
  • cost of a 20' incandescent string of lights is $1.98, an equivalent led string is $10.98
  • i pay 10.58 cents per kwh of power (this is based off the >1,000 kwh rate as i'm always over that mark and uses the 'winter' vs 'summer' fuel surcharge rate schedule because i use my lights in the winter
  • i run my lights for about 35 days a season, totaling 192.5 hours of usage

so, without further adieu, i'll cut to the graphic that could have just as easily stood on its' own:

the x-axis is time in years and the y-axis is the tco including purchasing the lights and the cost of power to run them.  it takes 13 years for you to save any money by purchasing led lights, and that's assuming that all of the led lights you buy today still work 13 years from now.  the slopes of those two lines *are* pretty different, and if you extend the timeline out to 20 years, you do end up saving about $100, but seriously, why pay 4x the cost up front to save $5 a year over 20 years?  if you think that's a good value proposition, i think you may have slept through the day in econ 101 where they talked about the time value of money.

the only reason i can come up with as a compelling argument for led is that it uses less power so it's better for the environment if you're hip on being green.  but wait, they may not be as green as you think.  leds contain a multitude of heavy metals which makes recycling them more difficult than incandescent lights, so those heavy metals will probably end up in your landfill eventually where they can leach into your ground water.

in short, i see led as just another marketing gimmick trying to pull a fast one on shoppers that don't take time to think before they buy.  don't get me wrong, i think led is a great technology and is definitely a big part of the future of lighting, but before i jump on that train they need to do something about the price.  maybe in 10 years it won't take 13 years for leds to pay for themselves.