Are LED Christmas Lights Worth It?

For the last few years I have been toying with the idea of replacing our standard incandescent mini Christmas lights with LED light, but I've always had a hard time justifying the cost.  I know the LED version uses about 90% less energy and they are suppose to last longer, but will they really save me enough money over their lifetime to justify their price?  To figure out if it is worth it to replace my old lights with LED Christmas lights I needed to calculate the break even point of the LED lights.  Scroll to the bottom to see the quick breakdown or continue reading to follow my math.

We're currently using 1,300 mini incandescent Christmas lights to decorate the exterior of our house.  To be very specific - 13 strings of 100 lights.

1,300 Christmas lights on our house

Based on my research, you can purchase a string of 100 mini LED Christmas lights for about $12.00.  Of course it is even better if you can find them on sale, but let's assume this is a pretty standard price.  To replace all of our current lights we will need 13 strings of 100 LED lights.  Total cost of purchasing the lights will equal $12.00 x 13 = $156.00.  For comparison, a box of 100 mini incandescent lights costs about $3.00.  $3.00 x 13 = $39.00.  Enough LED lights for our house would cost $117.00 more.

Each string of 100 lights uses just over 40 watts.  By multiplying 40 watts x 13 strings we get 520 watts.  Meaning, the total power consumption of our outdoor lights is 520 watts.

Our lights run for a total of 6 hours per day.  We use a little timer that turns them on when it gets dark and runs them for 6 hours.  Burning the lights 6 hours per day (520 watts x 6 hrs) we are using 3130 watt-hours or 3.13 kWh each day to power our outdoor lights.

Assuming now that we start burning our lights on December 1st and keep them up for 31 days, our total power consumption is 3.13 kWh x 31 = 97.03 kWh.  Our current electric rate is $0.06906 per kWh.  By multiplying the total number of kWh used (97.03) by our electric rate ($0.06906 per kWh) you get the cost of running our outdoor incandescent Christmas lights for the season.  97.03 kWh x $0.06906 = $6.70.

Let's do the same math with LED Christmas lights.  A string of 100 lights uses about 5 watts.  5 watts x 13 strings = 65 watts.  65 watts is quite a bit less than the 520 watts I'm currently using.  Let's figure out how much it costs to run them.  65 watts x 6 hrs/day = 390 watt-hours used in one day or 0.390 kWh.  A full season running the LEDs would be 0.390 x 31 = 12.09 kWh.  To calculate the cost we multiply 12.09 kWh by our electric rate of $0.06906.  12.09 kWh x $0.06906 = $0.83.

Wow! Only 83 cents to run the same amount of LED lights for a season!  That equals a savings of $5.87 each year on our electric bill.  But, with only $5.87 in electric savings per year it would take almost 20 years of running the LED lights to make up the difference.  The total cost of buying and running LED lights for 5 years is $160.17.  The total cost of buying and running incandescent Christmas lights for 5 years is $72.50.  I'll stick with the old fashioned mini incandescent Christmas lights for now.

Cost comparison of buying and running LED vs Incandescent Christmas lights