Window Restoration Guide

Window Restoration Guide

Window Restoration


Historic preservation is not just about preventing the demolition of a building. If preservation advocates truly want to ensure that our historic environment will be passed on to future generations, then we need to provide resources so that the individual parts that make up the sum total of that structure can be repaired, maintained and in some cases recreated.

Case in point is the retention of historic wood windows. For far too long, we have allowed otherwise repairable wood window frames and sashes to be thrown into a landfill when they could have been easily repaired.

In an effort to bring attention to this alarming loss of historic fabric, Preservation Chicago listed The Old Fashioned Wood Window as one of our 7 Most Endangered in 2009.

To further that initiative, we provide the following resources:

Report from from the National Trust for Historic Preservation’s Preservation Green Lab examines and compares options for window improvement.  


Report Findings:
  • Retrofit Measures Can Achieve Performance Results Comparable to New Replacement Windows. When the performance for each upgrade option is taken into account, this study shows that there are readily available retrofit measures that can achieve energy savings close to new, high performance replacement windows.
  • Almost Every Retrofit Option Offers a Better Return on Investment than Replacement Windows. Findings from the cost analysis showed that new, high performance windows are by far the most expensive measure, costing at least double that of common retrofit options when considering materials, installation and general construction commonly required for an existing home. In all climate zones analyzed, cellular shades, interior storm panels and various exterior storm window configurations offer a higher average return on investment compared to new, efficient replacement windows.
  • The Bottom Line. Retrofitting windows with high performance enhancements can result in substantial energy savings across a variety of climate zones. Selecting options that retain and retrofit existing windows are the most cost effective way to achieve these energy savings and to lower a home’s carbon footprint. Retrofits extend the life of existing windows, avoid production of new materials, reduce waste and preserve a home’s character.

Additional Resources