Tilt-in, double-pane, sash-only replacement kits provide a convenient way to convert old windows into efficient ones, if your existing frames are in good condition.
Window wizardry
November 2012
By JIM DULLEY
Question: Our house has its original single-pane windows, and we always feel chilly near them. Replacements can be expensive—I’m not sure it’s worth the investment. How can I improve the efficiency of the old windows?
Answer: I’m not surprised to hear you feel chilly near old single-pane windows on a cold day—they typically have huge heat loss and cold-air gain because of poor caulking and weather stripping. You probably also feel hot near them during summer.
Replacing those old windows can certainly boost energy efficiency, as much as 7 to 15 percent, according to the U.S. Department of Energy’s Energy Star program. But many factors—such as the type of window chosen, its materials and proper installation—will affect how much actual savings to expect.
“Replacement windows offer much more than just the financial payback—they can add aesthetic value and comfort, and they function much better,” says Michael Smith, manager of energy programs for Central Electric Power Cooperative.
But given the cost and trouble to install replacements, homeowners may want to explore other options for increasing energy efficiency, he says.
You can do many things on a limited budget to improve the year round efficiency of your windows. Before you attempt any improvements, though, first check the caulking and weather stripping on your windows to be sure the framing is not deteriorated. Fix any subpar conditions you find, or your improvements won’t be worth much.
Installing insulating window shades or curtains is one way to increase the insulation level of the window opening and to prevent radiant heat loss through the window. Simple options like pull-down pleated shades or closed Venetian blinds can block your skin’s exposure to the cold outdoors.
Efficient window shades can add significant insulation to your windows. Multilayer roll-up shades with a heat-reflecting, airproof, inner film layer can greatly reduce radiant heat loss during winter (or gain during summer).
Window films can help reduce wintertime heat loss. The newest energy-saving permanent films have just a slight tint, so they can’t be detected, and they use the same type of microscopically thin, low-emissivity, metallic coating as expensive replacement windows. Simple vinyl, static-cling film will also help a bit. But before installing anything on double-pane windows, check the window manufacturer’s warranty regarding film application.
Do-it-yourself, energy-saving film installation kits are available at most home improvement stores. Depending on your climate, you may want to choose a darker tint if summertime heat gain is your most significant concern.
To allow for seasonal changes, try installing window awnings for shade in combination with a lighter film on south-facing windows. This will block heat when the sun is higher in the sky during summer and allow for some passive solar heating from the lower wintertime sun.
A final option is to install a tilt‑in, double-pane, sash-only replacement kit. If your existing frames are in good condition, this will convert your old windows into very efficient ones. Plus you’ll get the convenience of tilt-in sashes for the ease of cleaning both sides of the window glass from indoors.
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