Improving the Energy-Efficiency of Existing Windows

We’ve talked about selecting energy-efficient windows. But, if purchasing new windows is out of the budget, there are ways that you can improve the efficiency of your existing windows without a big investment in time or money. You can use any or all of these methods of keeping your conditioned air from leaking out through windows, and it’s well worth the effort. Sealing up your windows can save 30% of your heating and cooling from literally going out the window.

Adding storm windows
If you have old windows, the best solution is to replace them. However, if that isn’t possible, a less expensive option is to use storm windows. Some types of storm windows are also a good option for those living in apartments.

Even though storm windows add little to the insulating performance of single-glazed windows that are in good condition, studies have found that they can help to reduce air movement into and out of existing windows. Therefore, they help reduce heating and cooling costs. Storm windows are available for most types of windows, and they can be installed on the interior or exterior of the primary window. They range from the inexpensive plastic sheets or films designed for one heating season, to triple-track glass units with low emissivity coatings that offer many years of use.

Mid-priced storm windows may use glass, plastic panels, or special plastic sheets that have specific optical qualities. Those made of polycarbonate plastic or laminated glass also offer a high degree of resistance to breaking during storms and/or from intruders.

Caulking and weatherstripping
Most experts agree that caulking and weatherstripping—two simple air sealing techniques—will pay for themselves in energy savings within one year. Applying these techniques will also alleviate drafts and help your home feel warmer when it’s cool outside.

Before air sealing your home, you should first detect where the air leaks are coming from. For a thorough and accurate measurement of air leakage in your home, hire a qualified technician to conduct an energy assessment, particularly a blower door test. This test, which depressurizes a home, can reveal the location of many leaks. A complete energy assessment will also help determine areas in your home that need more insulation.

Window treatments and coverings
You can choose window treatments or coverings not only for decoration but also for saving energy. Carefully selected and installed window treatments can reduce heat loss in the winter and heat gain in the summer. This might include awnings, blinds, draperies, insulated panels, shades, shutters and films.

Window treatments, however, aren’t effective at reducing air leakage or infiltration. You need to caulk and weatherstrip around windows to reduce air leakage.

These affordable solutions to leaky windows help keep your conditioned air where it belongs. However, if your home has very old and/or inefficient windows, it might be more cost-effective to replace them than to make these improvements. New, energy-efficient windows eventually pay for themselves through lower heating and cooling costs.


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