If your antique home has the original windows and they need work and the thought of replacing with modern day windows is something you don't want to do, read about this company who specializes in restoring old windows. I love the name of this company "Window Woman of New England". She was featured on "This Old House". I was reading her web site and came across this bit of information about old windows and energy efficiency.
According to the Field Study of Energy Impacts of Window Rehab Choices conducted by the Vermont Energy Investment Corporation, the University of Vermont School of Civil and Environmental Engineering and the U.S. Army Cold Regions Research and Engineering laboratory the estimate first year energy savings between a restored wooden window with a good storm window vs. a replacement window was $0.60. Yup, less than a buck. In their conclusions section they noted "The decision to renovate or replace a window should not be based solely on energy considerations, as the difference in estimate first year savings between the upgrade options are small." Broken glass, failed glazing, no weather stripping - these small and repairable items are what really effect energy efficiency in windows.
Interesting . . . if you have interest in restoring your windows - check out her website!