One of the most iconic holiday movie scenes of all time occurs when Clark Griswold finally succeeds in lighting the family Christmas lights: all 25,000 of them (not counting the Santa, the eight tiny reindeer, and the “Merry Christmas” sign).
Once lit, the Griswold house in National Lampoon’s Christmas Vacation is so bright that the lights actually blind the neighbors. Now, clearly this is a comedy with a lot of exaggeration involved, but even so, energy nerds like us at Energy Center of the World can’t help but ask: how much energy was Clark really using, and what would it cost to light that house?
If you need a refresher on the scene from this classic holiday hit, we have you covered.
How Much Electricity Were The Griswolds Really Using With Those Lights?
One 100-count string of incandescent lights uses about 40 watts of electricity. Griswold (appropriately nicknamed “Sparky” by his wife) proudly announces that he has strung 250 of them around the house for a total of 25,000 bulbs. So, 250 strings of (today’s) 100-count lights use approximately 10,000 watts, or 10 kilowatts (kW).
To provide some context: an average suburban household uses about 1 kW in a month. Clark put ten times that amount of electricity demand on the grid instantly . . . just from his house.
That kind of usage might make the Griswolds’ electric meter spin at a breakneck pace, but it probably wouldn’t require the local utility to fire up its auxiliary nuclear supply, like it does in the movie. In today’s neighborhoods, demand response programs might eliminate the need for peaking power plants.
What Would This Cost Today?
Lighting an entire house to this extent with incandescent “twinkle lights” can’t be cheap. Two hundred and fifty strands of them would have an upfront cost of about $3750 alone!
Using today’s average energy prices in the US, 10kWh of electric use would set Clark back about $1.19 per hour – a hefty electric bill if he keeps those lights on too long. Eight hours would cost him $9.52, so that’s basically an extra ten dollars per day to keep the house lit. Keeping it lit eight hours a day for the entire month of December would mean an extra $295.12 on his energy bill.
Today, Clark might opt for strands of LED or light emitting diode lights. A comparable 100-count string of outdoor LED lights boasts 85 percent reduction in energy consumption compared to incandescent lights. It’s true, the LED strands will cost a bit more. At around $15 per strand, the upfront costs of 100 strands is about $5000.
But, one string of lights only uses about six watts compared to the incandescent’s 40 watts. All together, the Griswold house would be using a mere 1,500 watts of demand, or 1.5 kW.
Over time, lighting the Griswold house with LED lights would cost only about $1.50 per day. That’s a savings of $248.62 over the course of one month. Consider the fact that those LED lights will keep the house festive for several years, and there’s big savings in investing in those bulbs.
So, while you (hopefully) don’t plan on using enough lights this year to black-out the neighborhood, incandescent lights are clearly not easy on your holiday budget. Opt for LEDs. They might cost a bit more at the register, but they will give you the gift of energy savings year after year. Happy holidays, everyone!