There is significant decay of the wood elements. When the glass is loose or more than one third of the putty is missing or loose. All other hardware, weather stripping or pulley and rope problems are presumed present to a degree, and corrected as part of the sequence of sash restoration.
If your house was built before World War II think of it more as an antique than an old house. Its future value and present charm can be measured to a large degree by the way in which it has been cared for and kept original.
Windows are essential fabric in maintaining the history of domestic architecture, keep them and you will be glad as will future owners of your house and your neighbors.
Removing calcified putty and paint from the glass risks glass breakage and scratching and this is not in this scope. See Glass Restoration Conservation
Traditional Double Hung Windows
Window includes: zinc or bronze interlocking weather stripping at perimeter and meeting rails, putty work, glazing, historic glass, sash, mortise, and tenon, as well as all mechanical hardware, including sash locks, cords, and lifts.
French, Hardware Restoration, Stays, and Latches
Insulated Glass in Historic Sash
Insulating Glass, Stained Glass in Insulating Panel, Retrofitting Insulating Glass, Insulating Glass Conversion
Window Work Procedures
Window Restoration
