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A well restored and weather stripped 1859 wood window with storm window. Source: Bob Yapp

One of the most important architectural features on your historic house or building is its original windows. Your original windows add texture, depth and aesthetic appeal to your historic structure. According to the Secretary of the Interior Standards for Rehabilitation, replacement should be the last resort for any character-defining feature in a historic structure. Before you order new windows for your historic house or building, contact a window repair contractor who has experience with repairing and restoring original windows.

If you restore your original windows correctly, they will be as (or even more) energy efficient than replacement windows. They will also cost less and provide a payback much faster than a replacement window.

Historic Windows are Sustainable

Your original windows have probably been in service for as many years as the age of your house or building. This could be 50 or even 150 years. Historic windows can be repaired cost effectively and made as (or more) energy efficient than most replacement windows. After you complete repairs on your original windows, they could last another 50 years before they need to be restored again. That kind of longevity makes your historic house and its windows extremely “green” on any sustainability scale.

You may have been convinced by some common myths about historic windows (see sidebar) that your original windows need to be replaced. However, you can hire skilled tradespeople who will be able to successfully repair your original windows. Some of the best window repair contractors are exterior painters and carpenters, because historic wood windows were assembled similar to a cabinet or piece of furniture.  A skilled contractor can quite easily take apart a historic window, repair it, and put it back together again. Contractors can also strip lead paint and apply new prime and finish paint coats to original windows. 

Historic Windows are Energy Efficient

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Caulking the exterior window casing trim to stop air infiltration is one way to help the energy efficiency of historic windows. Source: Bob Yapp

Research has shown that an old or historic window can be made as or more energy efficient than a replacement window. Weatherizing a historic window and adding a storm window will improve the energy efficiency of your original windows.

You can keep your original windows and even save money in the process. If you replace the original windows in your house, you are tossing out a system that has functioned well for 50 to 150 years.

Before 1900, most historic structures had double-hung window units. A double-hung window has a sash on the top and a sash on the bottom that operates with a simple sash rope, pulley, and cast-iron counter weight called a sash weight. With this system, the top sash could be lowered six inches and the bottom sash raised six inches. During the hot months of the year, double-hung windows acted like an early air conditioning system, allowing the hot air to escape through the top opening and bringing cooler breezes in through the lower opening.

Historic Windows have Storms

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A well-fitted wood storm window is also key to improving energy efficiency. A flush-mount metal storm window is also appropriate. Source: Bob Yapp

For the original owners of Wisconsin's historic houses and buildings, the primary window sashes were precious. These sashes were never intended to take a direct hit from the weather. House and building owners protected their windows with exterior, operable storm shutters. Millwork catalogs in the 1880s advertised wood storm windows and wood screens as a way to protect windows and save energy. Most historic Wisconsin houses built after the 1880s and up to the 1950s had exterior wood storms and screens. Because new windows don't have storm windows, they are not protected and tend not to last as long as historic windows.

Many homeowners later replaced their wooden storm and screen windows with aluminum, self-storing storm windows. By using these new self-storing storm windows, homeowners no longer needed to climb ladders in the spring and autumn to switch out their wood and glass storms with wood and screen storms. However, the design of self-storing windows created a new issue. Self-storing windows have a screen on the bottom half but not on the top half, so the self-storing storm windows prevented people from using their double-hung windows the way they were intended. Over time, homeowners tended to forget that the top sash of their double-hung windows could be opened. Their original windows got much less use, and they paid less attention to window maintenance. Some homeowners even painted the top sash shut. If this has happened to your historic windows, contact a window repair contractor to restore your windows to their original operating condition.