If you would ask some historians about window replacement in a historic home, they would answer you loudly…..”don’t replace but instead repair it”. The windows (as well as the milled woodwork) in an old house are indicative of the era it was built. Just because the windows look inoperable, don’t give up on them quite yet. Take a crack at trying to determine how to fix them and how much it will cost. You are undermining your love of historic preservation if you don’t attempt it. If you do swap out windows, the Historic Society may take the designation from you turning it into just another old house.
A window restoration can include repairs, glazing, weather stripping and possibly the addition of an outside storm window. The window should work as it was designed in the period it was built. Sash windows were the norm in historic homes. Generally speaking, the cost to repair an old sash window is on par with a high end sash replacement. The biggest enemy with using the old windows is energy loss through drafts or the deterioration of weather stripping if there even was any. You may want to have an experienced window restorer in Baltimore explain the best way to take a sash window apart. If they are painted shut, use a painters “5 in 1” tool and a utility knife to score the paint where it has formed a seal from multiple paintings. You may find damaged wood when you are scoring. The damaged wood will eventually need to be dug out and filled in with an epoxy. A historic window can be made thermally efficient by the installation of an outside storm window. Wood is a better insulator than metal so the addition of the storm window will get a higher efficiency rating that a metal replacement with the same outside storm window. After you have completed the restoration, there are a few simple things to do. Make sure you regularly examine the window for structural failure that you thought was corrected. If you have found any issues, remedy them as soon as possible.
If restoration of an existing cannot be completed because deterioration and decay are extensive, then the decision to replace it is the only choice. Once your decision is made, don’t quickly go out to a window dealer pricing windows of similar size looking for a cheap price. Instead, study the characteristics of the window you are replacing. Look as close as you can for a window that will match the characteristics of the old one. Check building supply firms, specialty woodworking mills, carpenters, preservation oriented magazines and historic preservation societies and groups. You can find many of these places by surfing the internet. Energy efficiency will definitely be one of the factors in support of replacement but don’t let this issue dominate the decision. Look at all the surrounding variables.
Preservation Societies recommend the repair and retention of the original windows if at all possible. Many windows, old and new, are replaced because of the lack of knowledge of repair and the ability to weatherize. Wooden windows that are properly restored and maintained will have been given a second chance in life while maintaining the historic character of the home.