Are LED Christmas Lights Really more Cost Effective?
Posted: December 9th, 2008 | Author: Joe | Filed under: Saving, spending | Tags: Christmas, LED lights, spending | 7 Comments »It’s that time of year again. I’m talking about that age old tradition of going Griswold on your house in the hopes of out doing your neighbors in the ever escalating war of holiday festivity.
This is our first Christmas in our new house, and we never really had anything to hang icicle lights off of in our old house. So, this past weekend I headed off to our favorite home improvement box store in search of icicle lights. Being the frugal person (cheap S.O.B.) that I am, I wanted to check out the LED icicle lights. LED’s use much less (about 80% less) energy than traditional, incandescent bulbs. The problem was they cost $15 more than traditional bulbs!
I had to do a quick gut check. The LED icicle lights were $19.99 for a strand of 300, while the old, evil energy hogging traditional lights were a mere $4.99 for 300.
“But the LED lights use 80% less energy!“, I told myself.
“Self“, said the other voice in my head (yes, there are often 2 voices in my head…. kind of like those old Tom and Jerry cartoons, when Tom has the devil on one shoulder, and an angel on the other…but I digress), ” it’ll take forever to use enough electricity to make up the price difference – do the math!”
Well, I may be a geek, but I’m not so bad as to whip out the pencil and paper right there in the store. People were already looking at me strangely. Besides, I wasn’t sure what I actually pay for electricity anyway. So, I trusted my intuition, and stuck with the tradition lights, at $4.99 a box.
Doing the math.
So, did I make the right decision? Here’s the breakdown…
The givens:
Traditional (incandescent ) bulb icicle lights: $5 for 300
LED icicle lights: $20 for 300
That’s a difference of $15.
The basic unit for measuring electricity cost is the Kilowatt hour (kwh). The way the power company determines the amount you owe each month is to take your rate (price per kwh) times the amount of kwh you consumed for the month:
Electric bill amount = (price per kwh) x (kwh used)
With me so far? Good.
Now, it’s the same formula for determining how much a certain device (i.e. icicle lights) will cost:
Cost of device = (price per kwh) x (kwh used by device)
I know the cost is $15, because I want to find out how long it will take to actually use $15 worth of electricity, so my formula actually looks like this:
$15 difference = (cost per kwh) x (kwh used)
Now, I’m trying to solve for the kwh used, but in order to do that, I need to figure out how much I pay for electricity per kwh used. That’s where the Residential Electricity Prices: A Consumer’s Guide brochure comes into play. I live in the once great state of NY, so I pay 14 cents per kwh. BTW: The chart on the website accounts for supply and “delivery” charges, and it actually matches what I have on my energy bill. Imagine that.
So, armed with this new information I now have:
cost per kwh used = $0.14, which gives us:
$15 difference = $.14 x kwh
Applying some basic algebraic jujitsu from my high school days gives me:
kwh= $15/$0.14
kwh = 107
OK, well that doesn’t really give me much here, does it… hmm.. 107 Kilowatt hours. Now to get something approaching a meaningful value, I need to find out how long it will take my strand of 300 traditional icicle Christmas lights to consume 107 kwh. To answer this, I need to know how many watts in a strand (because icicle lights consume watts of energy, not kilowatts..).
LED Christmas lights are more efficient, but are they a better buy?
After a little digging, I found it:
w=0.425 per bulb
So, total watts for the 300 light strand is :
300 bulbs x 0.425w = 127.8w per strand
… and, let’s see.. kilo means thousand, so 107kwh = 107,000 watt hours… which gives us:
Watts to reach $15 (107,000w) divided by watt usage in the strand of lights (127.8w) = number of hours the lights must be on before it costs $15, or to put it another way:
107,000 wh / 127.8w = 837.25 hours
so it will take 837.25 hours (35 days) of continual use before I spend $15.
Are LED Christmas lights worth the extra $15?:
I plan on using my Christmas lights for about 3-4 hours most nights. Being liberal in this usage, say 4 hours every night that the lights are up (maybe 45 days, again being very liberal) that would give me a total running time of 4hrs/day x 45 days or 180 hours. At this rate, it will take me a little over 4 and a half years to burn $15 in electricity.
Of course, that’s assuming the cost of electricity remains at 14 cents/kwh..
Keep in mind, I am not saying that LED bulbs are not more efficient than incandescent (they are vastly more efficient), but I am saying they are not worth an extra $15. The better idea is to wait and buy them at a discount after the holiday season, or wait until they come down further in price, perhaps in 5 years. 
House photo by Hendricks_NY
LED photo by slworking2
What others are saying