It’s that time of year; the temperature drops at night, your house feels drafty, and around mid-October the heat turns on (unless you’re way down south). You wonder why your house is so cold and how you can make it warmer. Everywhere you read about new energy efficient windows and you consider replacing your windows.
Before you replace those historic wood windows, STOP! Your house is not losing its heat through windows; but rather, mainly through the roof and uninsulated walls. Keep those historic beauties in their frames! And if you have windows with real muntins and individual window panes, then you definitely have something worthwhile. The cost of replacing your historic window could take 100 years to make up for its cost.
Don’t believe me? Check out the Historic Windows Resource Page from Preservation North Carolina, and pay special attention to the NCPTT Testing the Energy Performance of Wood Windows in Cold Climates report and the replacement cost calculator from Historic Omaha. Note that it will take 41 years for the windows to pay for themselves!
Okay and aside from cost, we have to recognize the aesthetic value of historic windows and the historic value of these windows. Once removed, it is a part of the building that is gone forever. Windows are a very important part of architectural style. Take a look at this brief slideshow from the Preservation Alliance of Minnesota titled, “Historic Wood Windows: Why They Matter and How to Save Them.” Lastly, for a thorough review of why to retain and maintain historic windows, answers to your questions, window vocabulary, and resources, see the National Trust’s Window Tip Sheet. For repair information see Preservation Brief 9: The Repair of Historic Wood Windows from the NPS.
Do your research before believing the gimmicks of “energy efficient” window manufacturers and sellers. After all, they WANT you to replace your windows.
Preservation in Pink 
Just wondering – do you have any citations or other evidence that heat is lost through uninsulated walls and the roof? Also, is it a matter of heat leaking out, or the cold getting in (aside from the speed of molecules and chemistry)? It is definitely colder around the immediate area of my old windows than the outside (probably insulated?) walls.
Save the Windows!
Landau
Landau,
The variety of sources I listed above all provide substantial information about window replacement. For example, if you check out the links such as the National Trust Window Tip Sheet, it has a list of resources. The NCPTT report is the results of a thorough study.
Also, a lot of the energy loss can be prevented by adding storm windows. If you notice small hooks or latches or another fastening device on the window architrave (they seem irrelevant to shutters and look like they’re just hanging around) that is often for the purpose of holding a glass storm window in place, which is removed during the warmer months. Even the 1950s window of my parents’ house have that option, only not with latches. Instead another piece of glass can be slid down the track to the lower pane to add a buffer to the cold drafts. The replacement windows in my current apartment feel no different than historic windows in terms of the level of drafts. Another point is that the amount of energy lost through a window cannot be made up by new windows.
Energy savings is also about taking care of your house – constant maintenance, as any homeowner will attest.
Look up this article on JSTOR: “What Replacement Windows Can’t Replace: The Real Cost of Removing Historic Windows”
Walter Sedovic, Jill H. Gotthelf
APT Bulletin, Vol. 36, No. 4 (Jan., 2005), pp. 25-29
Published by: Association for Preservation Technology International (APT)
Stable URL: http://www.jstor.org/stable/40003160
See also this study from the Historic Preservation & Planning Program and the Univ. of Maryland: http://www.lib.umd.edu/drum/handle/1903/8401?mode=full
Does that help?
Anyone have other sources to add?
Hey just wanted to give you a brief heads up and let
you know a few of the images aren’t loading properly. I’m not sure why but I think its a linking issue.
I’ve tried it in two different browsers and both show the same outcome.