Your Old Windows

As the winter heating season quickly approaches, many homeowners begin to think about ways to save on heating costs. One seemingly-simple solution is to replace the old, drafty, wood windows with modern energy-efficient, double-glazed, “maintenance-free” windows. But doing this may compromise the historical look of an older home—no matter how hard manufacturers try, modern replacement windows rarely achieve the right proportion and detailing. So, is there a solution that will give both energy efficiency and historical authenticity?

In most cases, the answer is yes. Occasionally, due to serious damage or long-deferred maintenance, a window is beyond repair and will need to be replaced. But for most old windows, there is still a lot of life left if they are properly maintained or repaired. Unlike today’s run-of-the-mill replacement window, old windows were made with dense, old-growth wood and were designed to be repaired. There are windows that have lasted 100 years or more, and probably have at least another 100 years in them. Even if there is wood damage or rot, this can often be addressed by patching in small pieces of new wood or using modern epoxy consolidants. But this is just the extreme cases—most of the time the task of improving an old window’s energy efficiency is much simpler.

There are a few simple things that any competent carpenter or do-it-yourselfer can do to reduce heat loss through and around windows. The first thing to keep in mind is that glass is not a good insulator; whether old and single-paned or modern and double-glazed, windows are not that much better than an open hole in the wall. There are areas that can be addressed simply, though. Fix any cracked glass and failing putty to be sure that there are no areas where heat can be lost. The other major area of heat loss is through the rough openings in the exterior wall into which the window is installed—simply caulking around the window frame can often make a big difference. The window sashes themselves can be part of the problem, as well. If they don’t fight snugly, then they provide a place for warm air to escape or cold air to enter. If the sashes are loose, they can be removed fairly simply (and if you do, now is a good time to repair those broken or worn sash cords so that it is easier to open the windows once the weather warms up again). Some v-strip metal weatherstripping installed in the window frame can help to snug up the sashes and prevent drafts. A properly fitting sash lock will also pull the meeting rails (the bottom of the top sash and the top of the bottom sash) together to help seal the window.

Good quality storm windows are the last piece of the puzzle. These provide an extra layer of glass and create an air pocket that helps to reduce drafts and air infiltration. For exterior storms, be sure they fit snugly and that the frames are properly caulked. There should also be good, clear drain holes at the bottom so that any rainwater or condensation can drain out. Water is the biggest enemy of wood and can lead quickly to rot. Adequate drainage and a well-maintained coat of paint are the best defense. Interior storm windows are also a very good option. They provide the extra layer of glass on the inside, and versions on the market today can be virtually invisible.

For most windows, these repairs can be made for far less than the cost of a good-quality replacement window. Even if an individual sash is beyond repair, there are many good craftsmen in the area who can build a new sash that matches the original for far less money than a full replacement window. But how do the energy savings stack up? A recent study done in Vermont concluded that if you have good fitting, single-glazed windows plus good fitting storm windows, the energy savings by replacing them with new double-glazed windows amounts to only about $2/year per window. If you figure the differential cost between replacement windows and repair of existing windows, it could take decades to recover the added cost of replacement windows in energy savings. And, odds are, the replacement windows may not even last that long.

With proper maintenance, your repaired original windows can last another 100 years or more. The old windows are far simpler to maintain. The sash and pulley system is simple and easy to repair. Modern replacement windows use complicated systems of springs and balances—if they break they frequently cannot be repaired, but instead need to be replaced. If you choose not to replace the balances, the window can be difficult or impossible to open. If the glass on an old window breaks, a few dollars at the hardware store can buy you a replacement pane. If the glass in a modern double glazed window breaks or if the seal between the panes fails, leading to condensation and fogging of the glass, you may be out of luck. New sealed double-glazed panes can be expensive or impossible to find; you may end up having to replace the whole window again.

The bottom line is that keeping, repairing, and maintaining your house’s old windows can be just as cost-effective as replacing them. The added bonus is that your house continues to look as its designer intended, and the historic fabric of your neighborhood is preserved. Windows are one of the most prominent features on any building and changing them can drastically change the look of a home. Modern replacement windows often have to have wider rails and thicker muntins to support the added weight of two panes of glass. Vinyl or metal trim does not have the depth and detail of wood trim. New wood is not as dense and durable as the old-growth wood used in older windows and consequently will probably not last as long. Despite what the window salesman may tell you, newer is not necessarily better.

And if you’re still cold in the winter, you can always heed your mother’s advice—put on a sweater.

If you have questions, suggestions for topics we might address, or know of materials that have been helpful to you, please let us know. You can call the Resource Center at 215 247-0417 or e-mail us.