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Since I discovered the fun of plagiarism in my last column, I’ve decided to continue my life of crime by sharing an excerpt from the same January/February ‘08 issue of Preservation magazine. This particular issue, called “The Green Issue”, has a number of excellent articles related to going (or being) green. This excerpt comes from an article entitled, “A Cautionary Tale”, by Wayne Curtis.

“. . . Old windows, of course, aren’t often associated with ‘green’ these days. Quite the opposite. Ancient, paintflecked panes are pulled out every day, with new vinyl windows inserted in their stead by homeowners seduced by newspaper ads promising that you can “Save Energy Now!” for impossibly low prices, including installation. The aesthetic result? A building that had long worn elegant wirerimmed frames suddenly switching to clunky, Clark Kent glasses.

It’s a sacrifice, of course. But it’s for the greater good, because replacement windows make sense for environmental reasons, right? Not so fast. It turns out that windows—even old singlepane windows—are responsible for relatively minor energy loss in most buildings. ‘Only 10 to 12 percent of the total air infiltration in a building is through the windows,’ said [Walter] Sedovic [preservation architect in Irvington, N.Y]. ‘The cold isn’t being transferred through the glass. It’s through openings in and around the sash. The energy loss is mostly through the roof and through the sill.’ He suggested that ‘replacement walls’ or ‘replacement fireplaces’ would make more sense for the energy conscious. So why are we bombarded with ads for replacement windows? ‘It’s because windows are easy to construct, easy to transport, and easy to sell,’ he said. ‘But they’re the wrong idea.’

According to the Whole Building Design Guide, for instance, an older singlepane window has an insulation factor of R1. A modern doubleglazed window offers R3 insulation. Yet if the walls of a historic building have an Rvalue in the teens, ‘taking a window from R1 to R3 will not provide sufficient energy savings to offset the cost of replacement windows and associated waste,’ according to the guide.

What’s more, if your goal is to reduce overall resource consumption, restoring and maintaining old windows make sense in another way. ‘We call them replacement windows because you keep replacing them,’ Sedovic said, invoking the words of his colleague John Seekircher. When modern windows, with their high tech seals, eventually fail—and they will—the result tends to be catastrophic failure. You don’t repair them. You replace them. Anyone who doesn’t see something amiss in replacing centuryold windows with ‘environmentally responsible’ windows that will be junked and replaced every decade or two is suffering from an irony deficiency.”

Contact me with any questions you have about Historic Preservation issues at hp@mestapark.org.