Walking the floor of the International Builders' Show, it was easy to see one window material was on the rise: fiberglass. From color and sizing expansions to new models and shapes, a variety of window manufacturers worked to enhance their selection of the material.

EXPANSION PLANS: Weather Shield now manufactures fiberglass-clad wood windows, and Pella expanded its fiberglass Impervia line to include casement and awning options. "The sales of fiberglass have been tremendous," says Duane Putz, director of sales and marketing for Pella Corporation's advanced materials division. "The industry has started to recognize the benefits, and as people get more aware of that, we have more demand for the products."

Fiberglass remains a tiny part of the windows sector. Only 1.28 million units were sold in the residential new construction, remodeling, and replacement markets in 2007. That compares with 35.7 million vinyl windows that same year. But fiberglass shipments in 2007 rose 60% since 2003 and 6.2% since 2006, according to the 2008 U.S. Industry Statistical Review and Forecast by the American Architectural Manufacturers Association and the Window & Door Manufacturers Association. Fiberglass is the only material that consistently showed growth in the report, and it is predicted to keep rising in sales through 2011.

The material's popularity stems from its many benefits. It is stronger than vinyl and aluminum; insulates better than aluminum; requires less maintenance than wood; and resists fading, which allows it to come in dark colors and to be painted. Additionally, because fiberglass is mostly made of glass, it expands and contracts at the same rate as window glass, which means less chance of failure or sealing problems, resulting in fewer callbacks.

But fiberglass also costs more than aluminum or vinyl. "I get a lot more questions about it–people wanting to pursue it or possibly go that route, whether because of its strength or its green properties," says Dave Megge, vice president of Quality Lumber & Building Wholesalers in Columbus, Mich. "But, the bottom line also comes to price. People tend to go the other route, sometimes because of money."

Ryan McGraw, a principal at Revolution Building Supply in Baltimore, says fiberglass windows have fit well into light commercial applications. He says fiberglass lowers the chance of leaks and insulates better than commercial, all-aluminum windows.

Chris Sargis, branch manager at Johnson Brothers in Boise, Idaho, offers fiberglass windows as an upgrade for entry-level houses. The product is more expensive than vinyl, he says, but less costly than his higher-end, all-wood windows.

"In our region, we see people getting away from light colors," he says. "So, this is one product we can offer and also guarantee that a paint finish is not going to fade."

Manufacturers have also noticed a growing interest in fiberglass and are expanding product lines accordingly.

"It's hard to gauge the level of popularity the way the market is," says John Kirchner, public relations manager for Marvin Windows and Doors, "but we are seeing more focus and attention [on the material]." Marvin offers fiberglass options in its Integrity line of Ultrex windows. The company added an ebony color to its all fiberglass windows at the Builders' Show. It also introduced new simulated divided lites for its wood and fiberglass window.

Milgard Windows & Doors added a mahogany option to its fiberglass window with a wood veneer interior, and Pella now offers casement and awning fiberglass windows. Weather Shield added to the mix by introducing a fiberglass window line.

Living on a lake, Megge says he sees the benefits of fiberglass every time he looks at the pounding of the waves. "They've been making boats out of fiberglass for as long as I can remember," he says. "Not many materials could stand up to that." If the price falls, he predicts fiberglass will boom: "I personally think that fiberglass is going to be the wave of the future."

–Victoria Markovitz