The Case for Keeping Your Old, Single-Pane, Double-Hung Windows
While Boston Building Resources is happy to sell you a new vinyl, wood, or clad replacement window, first, we would like you to consider the benefits of improving your existing wood windows and adding a quality storm window.
Most homes lose more heat through uninsulated walls and roofs than through windows. So, as you contemplate improving your home’s overall energy efficiency (starting, hopefully, with a comprehensive energy assessment), insulating your roof and walls is likely the best first step, and air sealing is the next best step.
Addressing the efficiency of your windows is also an important action toward improving your home’s overall comfort and energy usage. We believe that, in most cases, tuning up your existing primary double-hung windows and adding a quality storm is the most reasonable step to take.
Old double-hung windows are an important character-defining feature of your home. In many cases, original double-hungs have lasted more than 100 years and, with some tender loving care, they will likely last another hundred. By maintaining your existing windows, you will keep the architectural integrity of your home’s original design intact.
Your windows are made from old-growth wood which, compared to new wood, is denser, naturally rot-resistant, and more dimensionally stable.
Keeping your existing windows also yields the largest daylight opening. Replacement windows typically come in a box frame that inserts into the old jamb opening; the actual glass size is reduced. While this may not be a big deal for larger windows, for smaller ones, it may be significant.
Tuning up your existing windows can be a homeowner-friendly project. With some basic training, which we are happy to supply, a handy homeowner can weatherstrip his or her windows and add a storm window.
Steps to weatherstrip your double-hung window include:
- Installing a seal around the perimeter (we recommend cushion bronze).
- Installing bulb weather stripping (vinyl or silicone) at the top and bottom sash and at the meeting rail (where the top and bottom sash meet in the middle).
- Making sure your lock works, not only for security reasons, but also to ensure that the meeting rails are pulled together tightly.
Once your primary window is tuned up, add a quality storm window such as the Harvey Tru Channel, available at Boston Building Resources. A storm window will create an additional air space for increased insulation and to further impede air infiltration. The storm will also protect your primary wood window from wind, rain, snow, and ultraviolet light. To increase the effectiveness of the storm, a low-E coating can be added to the glass.
The end result of properly tuned-up primary windows coupled with good quality storm windows is a fenestration system that maintains the architectural integrity of your home’s original design and that is every bit as energy efficient, if not more so, than a new replacement window which often detracts from your home’s design integrity.
A 1996 report prepared for the State of Vermont concluded, “Window upgrades using existing sash can achieve performance indistinguishable from replacement sash. . . . If the existing window is loose, it can often be cost-effective to address this leakage. . . . If the window is already in typical or tight condition, an upgrade is unlikely to be cost-effective. . . . If the windows have single glass, it is worthwhile considering installing a second layer, including the options of storm windows. . . .” Access the full report online.
