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Save a Window, Save a Tree
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Received an Innovative Commercialization Grant
from the U.S. Department of Energy in 1991

FAQs

Why should I try to save my wood windows?

One of the main reasons why homeowners choose their homes in the first place is the way they look, and the windows are a major factor in a home's overall appeal. Windows can add a distinctive look to any house. The older the home, the more important the aesthetics are concerning size, placement, and muntins. In fact, the things that most people don't like about their windows are that they are difficult to operate, are drafty, rattle, and are single pane, thereby requiring the unsightly triple track storm window. They love the look, but hate how they perform. Bi-Glass Systems help preserve the wonderful aesthetics, while upgrading the energy efficiency of the windows at a lower price than new wood windows.


Do historical societies approve of Bi-Glass Systems?

Historical preservation groups around the country are welcoming the Bi-Glass System with open arms. In New Hampshire and Vermont, historical preservation groups specify Bi-Glass as the renovation/restoration system of choice. Although there are preservation groups in some areas that are so restrictive that any upgrade is taboo, most groups welcome the diversity of options available, from using hidden balances and weatherstripping to completely changing out the single-pane glass to insulated units. Most historical societies are concerned that the exterior of historical properties remains the same. The Bi-Glass System maintains that look and still upgrades the window to higher energy-efficiency standards.


Will my windows be more energy efficient after Bi-Glass?

Windows are comprised of three basic components. Each has a direct impact on the energy efficiency of the window.

Jambliner & Weatherstripping System: This accounts for 50% of the heat loss in an old window and is usually a weight and pulley system that has no weatherstripping on either the horizontal or vertical surfaces. By installing a new compressible vinyl jambliner with silicone bulb weatherstripping at the horizontal joints, we virtually eliminate any infiltration at these points.
Weight Pockets: This area accounts for 30% of the heat loss in an old window. The cavities in the jamb that are used to house the weights are virtual wind tunnels that funnel air into the house. By filling these pockets with insulation, we stop the movement of air and eliminate infiltration at these areas.
Glass: This aspect of the window is responsible for 25% of the heat loss in a single-glazed window. By replacing the single glazing with insulated, low-E glass, we increase the R-value by three times, thus eliminating the convection currents that occur with single glazing. This increases the energy efficiency and the comfort factor for anyone sitting near a window. No more drafts!


Are new wood windows better than my old ones?

New wood windows are manufactured using the current fast-growth pine. While relatively stable as a building material, this fast-growth wood has a major drawback. It has a tendency to rot more quickly than older growth southern yellow pine or long leaf pine, the wood with which older windows were commonly made. The growth rings on fast-growth pine are over twice as wide as the slow-growth wood. The soft (wide) section of the growth ring (summer growth) is more susceptible to rot than the hard (narrow) section (winter growth), which is more impervious to the elements. The wider the rings, the more potential for degradation of the wood. Southern yellow pine is relatively rare now and not used for window manufacturing. It is rich in pitch, which inhibits rot, and has very tight growth rings. Older wood is far superior to newer fast-growth wood for longevity. This is why we encourage homeowners to save their existing sash by updating with the Bi-Glass System. Most older windows are in the 50-to-100-year-old range and in very good condition. Treated correctly, they can last at least 50 more years!

Why is wood better than vinyl for windows?

About half the residential replacement windows sold in the U.S. are made of vinyl. At first glance, vinyl seems to make sense. Manufacturers are justified in their claims that it insulates well and never needs painting. But vinyl isn't nearly as rigid as other window materials, such as wood and fiberglass. Worse, vinyl begins to soften and distort at 165 degrees, a temperature that is easily reached in the space between a window and drape on a sunny day. Although all window materials expand and contract as temperatures rise and fall, vinyl moves more than twice as much as aluminum, wood, and fiberglass. Vinyl expands seven times farther than glass with each degree. That action can pop seals between the frame and the glass. Last year, Environmental Building News, a newsletter for contractors and architects, evaluated all framing options used in windows and advised readers to avoid 100% vinyl window frames because of their durability problems.

Andersen Corporation™, the world's largest manufacturer of windows, has never made an all-vinyl window for sale in the U.S. "Vinyl simply is not suitable for use on its own as a window material," says Mike Compeau, a spokesman for the company. Vinyl windows have been on the market for only 15 to 20 years. According the Hakim Elmahdy, the chief window expert for the Canadian government's Institute for Research in Construction, "There is not enough data or track record for these windows to say, yes, they will last for 50 years."

Noted Architect Robert A.M. Stern says, "We won't spec a house with vinyl windows. We won't even use a vinyl-over-wood window. We only use windows that are framed in wood. And we paint them or stain them. We don't leave a natural finish. The paint seals the windows."


Will my windows tilt in?

Yes! By installing vinyl tilt jambliners in place of your old weights and pulleys, you can tilt your windows in for easy cleaning and remove them for simple maintenance.


Is this an expensive process?

The Bi-Glass System is a licensed system. There is no standardization of prices between licensees. However, on the average, our system is from 10% to 60% less expensive than comparable wood SDL products manufactured by quality wood window providers. The best way to get a price is to contact your regional installer and ask for a quote specific to your windows.


If vinyl jambliners aren't appropriate, are there other options?

If your house is governed by a historical group that refuses to allow the use of vinyl jambliners, we can offer other systems that allow the upgrading of glass, weatherstripping, and locks, while maintaining the look of the old jamb and sash. We offer three options.

First, we can resize the existing weights to compensate for the increased weight of the insulated glass. The downside is that option doesn't allow the weight pockets to be filled with insulation. Option two is to install spring balances, which are cut into the sash and stay hidden from view. Option three is to install a tape balance, which is a system that can handle any weight and is installed into the same hole the old pulleys occupied. These hook to the windows with a flat steel tape. Option two and three offer the ability to insulate the weight pockets and eliminate that infiltration. All of these options require additional weatherstripping on the stiles (vertical sections of sash) with vinyl corner bead and felt stripping. While these options offer a definite improvement for old windows, the optimum weatherstripping system is vinyl jambliners.