General Electric Co., founded by inventor Thomas Edison, plans to close its last U.S. factory that makes common household incandescent light bulbs as demand rises for more energy-efficient lighting.

GE intends to close the bulb-assembly factory that employs 203 people in Winchester, Va., by July 2010, as well as a related glass factory with 125 employees in Lexington, K., the company said in a statement. A 109-worker plant in Niles, Ohio, that makes glass for spotlights also is slated to close.

The Winchester factory is GE's last in the U.S. to make common household bulbs, GE spokeswoman Deborah Wexler said in an interview. Workers will have 60 days to try to come up with cost savings that may save the plants.

Fairfield, Connecticut-based GE will keep making common bulbs outside the U.S., she said.

"The market for incandescent light bulbs has declined by 50 percent in the past five years," Wexler said. "Consumers have moved toward energy efficient light bulbs, and with governments around the world setting lighting efficiency standards, these will be legislated out of existence."

GE was formed in 1892 through the merger of the Edison Electric Co. and the Thomson Houston Co. Edison had invented the first commercially practical incandescent lamp in 1879, according to a timeline on GE's Web site.

The company will still make specialty incandescents such as halogens in Warren, Ohio, and parts at other Ohio and Pennsylvania sites, spokeswoman Janice Fraser wrote in an e-mail.

The Mahoning glass plant in Niles is only running part-time because of declining demand, Fraser said. If it were to close, a facility in Somerset, Kentucky, that also is running part-time would begin full-time production again.

Most of the employees at the three plants will be eligible for a GE retirement package, the company said.