The Wrong Reason to Replace Drafty Old Windows (and the Right One)

Q: Our 90-year-old house has its original drafty windows. Should we replace them to cut our sky-high cooling and heating costs?

A: In a word, no. The energy savings from new windows don’t come close to justifying their cost. True, new high-efficiency (double paned, argon-gas filled, low-emissivity film coated) windows might offer twice the insulation value as the old single-pane units in your house, meaning they’d cut your energy loss through the windows by as much as 50%. But only about 30% of your house’s heating and air conditioning disappears out the windows, says Paul Scheckel, a home energy efficiency consultant in Vermont and author of The Homeowner’s Energy Handbook. So at best you’d really only save about 15% (calculated by taking 50% of 30%).

Thus even if you pay a whopping $2,000 a year in heating and cooling costs, your savings would only be $300. According to Remodeling magazine’s 2014 Cost vs. Value report, the average cost for replacement windows is about $11,000, meaning it’d take 37 years to recoup your investment.

This doesn’t mean it’s a bad idea to replace your windows. The study also showed that homeowners get back nearly 80% of window replacement costs when they eventually sell. Plus, new units tilt in for easy cleaning, and they open and shut with ease—no need to prop them open with a stick. You get to eliminate those ugly aluminum storm windows and can even choose units that never need exterior painting.

Just be sure to choose windows that match your home. If your 90-year-old building is an architectural charmer, you’ll want to mimic the old units’ “divided light” patterns (the small panes within the windows), and use high-quality wood windows that fit the historic look of the building. Otherwise, using an economy-grade window could actually detract from your resale value instead of increasing it.