Storm Windows – Worth the Investment?
I live in a historic district in Washington, DC where storms windows are regularly suggested as ways to save energy where single pane windows are common.
The only way that I can theorize that storm windows could be worth the investment would be if they were air tight and at some orientations, low-E coated.
Unfortunately, most of the storm windows that I see have large gaps, deteriorated weather stripping and lack low-E coatings.
I feel like storm windows are like fiberglass insulation, theoretically a good idea, but in practice never installed properly.
Is there a credible source that provides any research about the benefits or lack thereof?
Please help me settle this debate!
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Replies
Cliff,
The two studies that are cited most often are the following:
"Measured Winter Performance of Storm Windows," J. H. Klems, Lawrence Berkeley National Laboratory, 2002. Klems concluded, “The addition of low-e storm windows to the prime [single-glazed] window provided performance very similar to that of the replacement window [with low-e argon-filled sealed double glazing].”
"Field Evaluation of Low-E Storm Windows," S. Craig Drumheller, Christian Köhler, Stefanie Minen, 2007. Summarizing the findings of this Chicago research project in an article published in the February 2008 issue of Energy Design Update, I wrote, "Installing storm windows improved the homes’ airtightness between 5.7% and 8.6%. At 50 pascals, air leakage was reduced between 231 and 335 cfm. Energy used for heating was reduced by 8% to 18% in the homes that received clear-glass storm windows, and by 19% to 23% in the homes that received low-e storm windows. Although low-e storms cost more than clear-glass storms, they were shown to be far more cost-effective. The simple payback period for the two houses with clear-glass storms was 8.4 and 12.1 years (average, 10.3 years); at the two houses with low-e storms, the payback periods were 3.5 and 5.1 years (average, 4.3 years)."
Thanks for the response. I am surprised at the summaries, but it's good to know.
I have used Harvey Tru Channels on my house, and others, and they are well built, the moving sashes seal very tightly. Also available with low e. http://www.harveybp.com/product.aspx?pid=1
Even without low-e, they cut down on air infiltration, drafts, and noise tremendously, for a fraction of the cost of even a cheap replacement window. Although this is somewhat obvious, with a house with old windows, they have the added benefit of protecting the old sashes from weather. That can really help when you don't have the money or time to properly repair an old window. I can admit to going a whole winter with just a storm in a window that took me forerver to get to . . .
Not sure where a distributor would be in DC - it can be hard to find a distributor that sells directly to homeowners, Harvey works almost exclusively with contractors.