When the flick of a switch turns it into a giant television screen

The windows are the latest advance in a growing industry, fueled by record new-home sales, bigger and bigger houses, and a burgeoning remodeling industry.

In 2002, 56 million windows were produced in the country, up from 47.9 million in 1996, according to the Window and Door Manufacturers Association. New windows are purchased in about equal numbers for new homes and remodeling projects, according to the association.

Andersen's new entrant, which isn't for sale yet, is a bay window that doubles as a home entertainment center. A low-voltage current runs through the window. When the current is on, the window is clear. Turn the current off and the glass goes opaque for use as a projection screen for television or DVDs. Flanking casement windows become the speakers.

Windows may seem simple enough -- glass in a frame -- but a lot of technology has gone into them in recent years, mostly to improve energy efficiency.

The National Association of Home Builders estimates that windows are at least an $8 billion-a-year industry. Fifteen years ago, the average American home had 12 windows. Now, as homes get bigger and windows become more popular, the average home has 16 windows. Upscale houses of between 4,000 and 5,000 square feet have about 20 windows.

"Consumers want more light and more use of glass in their homes," said Gopal Ahluwalia, head of research at NAHB.

But do we really need our windows to turn into televisions?

"These are gimmicks," Ahluwalia said. "People like these types of things as topics of discussion. It's the 'We have it and only we have it' type of mentality. Only people with a lot of money will want them."

Andersen executives say that the entertainment-center windows are prototypes. They say they came up with the design after several years of research and countless focus groups.

The company envisions the windows being bought for the kitchen or family room. The projector, the hard drive of the computer or the stereo is elsewhere -- connected to the window but hidden in the seat of the bay window or in other furniture in the room. The entire system is set up so that when the window is turned to opaque, the speakers go on.

"The transformation is pretty startling," said Sandy Isenstadt, a professor of architecture at Yale University. "One minute you're looking out your bay window at your neighbor's backyard, and the next you're watching Tom Cruise and 'Top Gun.' "