Spectacular holiday light displays may delight the eyes — until December's electricity bill comes due.
A fairly modest display of, say five strands of lights, can add as much as 15 percent to a family's energy bill, experts say.
But because relatively few households decorate extravagantly with lights, the cost of extra lighting is hard to discern in regional energy demand records.
On a typical winter day, Xcel Energy Inc. delivers about 5,000 megawatts per hour at the peak, said spokesman Mark Stutz. Holiday lights add about one megawatt per hour, a fraction of a percent, he estimated.
Overall, though, the holiday season has a measurable impact, Stutz said.
"When you look at the malls staying open later, all the cooking, holiday parties, everyone being home ... we think that adds around 150 to 200 megawatts, about 3 (percent) or 4 percent," he said.
And for an individual homeowner, the choice to decorate lavishly with light can be costly.
A couple of strands of lights won't increase an individual's electricity bill by much, Stutz said. Depending on the type of lights people use, one strand of lights kept on for six hours costs between 1 cent and 8 cents, or 30 cents to $2.40 per month, he said.
"If you're using about 10 strands of lights, you might add $15 to your December bill," he said. In Colorado, the average household's monthly electricity bill in the winter is $45 to $50, he said.
Alek Komarnitsky of Lafayette estimates his 22,000-light display costs his family an extra $150 or so in December. The home, on Blue Heron Circle, blazes with outdoor lights — icicles, Santas, a snowman.
"The reality is the electric meter does spin like heck," Komarnitsky said.
This year, a Boulder resident challenged him to use Xcel's wind power program to pay for the display, and when the man actually mailed him a check to help do so, Komarnitsky complied.
Xcel gives its customers the option of paying a bit extra for "green power" generated by the company's wind turbines instead of its more conventional coal-powered plants.
Komarnitsky said he's not sure if he'll keep up the commitment to more expensive wind energy, though.
"Look, I'm already in hot water with my wife for all the time and money I spend on this," he said. "I just kind of enjoy doing the lights; I enjoy doing it for the kids. And you can't put up these lights without paying electricity for it."
Boulder's famous holiday star, a December fixture on Flagstaff Mountain every year since 1947, draws about $200 worth of electricity every year, said Colene Van Winkle from the Boulder Chamber of Commerce.
"The energy cost isn't much," she said. "The major cost for us is all the vandalism that happens to the star."
So far this year, vandalism damages have been minimal, though: The star is now rigged high off the ground and is less accessible to vandals.