Insulated Storm Windows?
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Author name: Alex Wilson Blog Category: Energy Solutions Can top energy performance be achieved by combining fairly standard windows with really good storm windows or even a second set of prime windows? A low-e storm window at my colleague Peter Yost's house in Brattleboro. Click on image to enlarge. Photo Credit: Peter Yost I’ve done a lot of digging into window options in the past few months—not only for a special report on windows that BuildingGreen published, but also for the renovation of the early-19 th -Century farmhouse that my wife and I recently purchased. The state-of-the-art with windows in terms of energy performance and quality is clearly seen in the triple-glazed European windows that are certified by the Passivhaus Institut in Germany. You can now buy these wonderful windows with unit center-of-glass R-values above R-9 yet high-enough light transmission to work well for passive solar houses (solar heat gain coefficient above 0.60). The problem is that these windows are incredibly expensive—some over $100 per square foot, which comes to $1,500 for a typical 3' x 5' window. You get a lot for that price in the way of top-quality materials, construction detailing, durability, thermal breaks, air tightness, and energy performance, but the windows are simply way above the budget range for most projects. Furthermore, replacing existing windows is often very hard to justify unless the existing windows are in very poor shape. read more