Efficiency vs. esthetics
Tips for upgrading windows to keep out the chill while preserving original style
Q We want to replace or reglaze our 1966 Colonial's three bow windows, which have single-pane glass puttied into wooden frames. Each window has seven panes 21.5 inches
(55 centimetres) wide by 17.5 inches (44 centimetres) tall and two slightly smaller sections that open. The wood is in good shape, but the windows are drafty and we get lots of condensation when the weather first turns cool in the fall or during cold snaps. Every solution that regular window replacement companies propose — usually vinyl — would totally change the look. At least a third of the open area would be obscured by wide vinyl mullions and rails. How can we upgrade these windows while keeping close to the look of the originals, which we love?
A You probably have a few options, but it depends on the details of your windows. One important thing to realize is that there are different types of window companies.
Some, like the vinyl salespeople you've talked to, specialize in selling whole window units, often ones made of only one material. Others focus just on the glass. And other companies specialize in restoring wood or metal windows, a service you don't need because your windows are in good shape.
If the exterior recess for the glass is deep enough, you may be able to replace the glass with dual-pane units. This would solve the condensation issue, but it wouldn't plug any draftiness around the window frame beyond the glass area.
Among all the options, this would best preserve the look of the windows inside and outside, said Mark Russow, president of Hodges Windows & Doors.
Multi-pane, or divided-light, windows add a lot to the appearance of a house, in part because light reflects from each pane a little differently. Light doesn't dance off the same way from windows that simulate divided lights by using grids to divide single panes into smaller sections.
The thinnest dual-pane glass units are three-eighths-of-aninch thick, but your window recesses would need to be twice that depth to allow space for moulding to keep the units in place. To arrange for an estimator to visit and evaluate your window frames, call a glass company. If your windows don't have the required depth around the glass, a carpenter could probably add moulding to make the recesses deeper, but that would boost the cost.
Another alternative is adding exterior storm windows, which would cost about US$1,500 per window, including labour and paint on aluminum frames.
To accommodate the bow, you would need five of these for each window, with each panel covering one stack of three small panes. Like dual-pane inserts, storm windows add an insulating layer of air space. If there is any draftiness around the existing window where it is covered by the storm windows, you probably wouldn't feel it, but condensation could still occur because of the air leaks. It would be on the inside face of the storm windows, though, not on the surfaces inside your house.
Small vent holes at the bottom of the storm windows would allow the moisture to evaporate when the glass and air space warm up. And condensation shouldn't be a big problem given that your windows are mostly fixed; it's a bigger issue with double-hung windows, which have more places for air to sneak through.
With storm windows, you would keep your original windows, and they would be much more comfortable to live with and more energy efficient. From inside, you would see a little of the storm window frame, but you would still have almost all of the light that you get now.
Downsides: On the outside, the light would reflect as if your nine-pane windows consist of five tall panes. And you would lose the ability to let in fresh air through the vent panes.
Replacing the windows, as you have already discovered, would change the look.
Even true divided-light windows made of wood these days have much thicker framing parts than in the past, says Russow, which may result in adding much more bulk to the appearance of your windows.