In a tightening economy that makes even a small increase in an electric bill loom large, energy-conscious consumers are changing the look of Christmas as they switch in record numbers from the familiar incandescent Christmas lights to light-emitting diode bulbs, or LEDs.

Sales of the newer bulbs, which require less power, are up 160 percent this year compared to last year, said Aaron Hassen, spokesman for Christmas Lights Etc., a Alpharetta, Ga.-based manufacturer and seller of Christmas decorations. The company sells about 26 million lights a year through its Web site, www.christmaslightsetc.com.

In past years, he said, the use of LED lights for Christmas trees and yard displays might have been considered a fad. But that changed with this year's energy crunch and a renewed focus on energy as a political issue. "People really started taking it to heart."

The resultant sales, he said, mark a tipping point for the holiday decorating industry. "Because they're spending more [on LEDs], supply and demand dictates that we will now be manufacturing more varieties of LED products."

Traditional incandescents aren't going away. They still represent about 90 percent of sales, Mr. Hassen said.

They also represent 90 percent of the bulbs used by Robert Cox, the Baldwin resident who has gained national fame for the Christmas display at his home at 1736 Beryl Drive.

This year, Mr. Cox and his wife, Raquel, have strung 200,000 lights across their home and yard in a computer-controlled display that winks and flashes in sync with an hour-long soundtrack.

This is the third year that the Coxes have created the light-and-sound display, which they also use as a fundraiser -- for Children's Hospital in previous years, and for St. Jude's Hospital this year. They have also gone multimedia, with a Web site, www.steelcitychristmas.com, that offers video clips of the display.

While Mr. Cox, a copier technician at Caltronics National in Scott, is using about 20,000 LEDs this year, he is not completely sold on their superiority.

In fact, he said, some manufacturers are "sort of jumping the gun" on releasing the new products.

Noting that there are two types of bulbs -- sealed, non-replaceable bulbs and replaceable bulbs -- he said the former are "very, very good lights." The latter have more issues because the aluminum contacts inside corrode easily.

When that happens, one of the much-touted advantages of LEDs, their long life, disappears.

"I have about 60 or 70 sets of LEDs that I used last year that I'm not using this year," he said.

Use of the energy-efficient LEDs notwithstanding, Mr. Cox said his electric bill rises by $400 to $500 during the six weeks that the display is in operation, far exceeding his average monthly bill of $100.

For most homeowners, holiday lighting does not create such a large electric bill, said Duquesne Light spokesman Joseph Vallarian.

"With a normal-sized Christmas tree, they're probably not going to see a lot of difference," he said. "With lights all over the yard, a Christmas tree and everything else, it can make a little difference, sure."

He said even the extravagance of some home displays does not translate into a large revenue increase for the electric utility.

"There is somewhat of a spike" during the holidays, he said, "but it's nowhere near summertime numbers." That's when sweating customers turn up the air conditioning, driving greater consumption.

Even so, the company has noted that an increasing number of consumers are inquiring about the cost savings benefits of using LEDs versus incandescents.

The savings are not dramatic but they grow over time, as the LEDs can last up to 30 times longer than incandescents.

And, according to a report commissioned by the U.S. Department of Energy, the use of the energy-efficient lights for holiday decorating could have a huge impact nationwide, because of the sheer volume of lights used -- more than 30 billion bulbs.

If the market shifted entirely to LEDs, the report said, the nation could save nearly six terawatt-hours of energy per year, enough to power almost a half-million households for a year.

Americans have been turning electricity into holiday cheer for decades. Edward H. Johnson, a friend of the famed inventor Thomas Edison, is credited with creating the first string of Christmas tree lights in 1882.

But it was President Grover Cleveland who brought indoor Christmas lights to the public imagination, by having the White House family Christmas tree illuminated by them in 1895, a tradition that continues today.

Yet even that tradition is changing with the new sensibilities. Last year was the first time that the White House Christmas tree was decorated with LEDs.