04/15/2026
The truth?
Original wood windows were built with old-growth lumber—dense, naturally rot-resistant, and designed to last a century or more with basic care.
But one of the biggest misconceptions is that old windows are the main source of energy loss in a home. In reality, the biggest losses usually come from elsewhere. According to the U.S. Department of Energy, heat loss can come from attic/roof insulation (up to 25–45%), exterior walls (up to 35%), and even leaky or poorly insulated ducts (up to 60% of conditioned air).
That draft you feel near your sofa?
It’s often not the window itself—it’s air leaks, failed glazing, worn weatherstripping, or deferred maintenance. And in most cases, those issues are repairable!! (Learn how to fix these issues at our upcoming Windows Worth Saving event)
Meanwhile, modern replacement windows are often made with fast-growth wood, vinyl, or composites that cannot be repaired once seals fail. Over time, that leads to replacement cycles—and waste. In fact, millions of windows end up in landfills each year, many of them less than 20 years old (City of San Antonio Office of Historic Preservation).
There’s also the cost factor. Research from the National Park Service and the U.S. Department of Energy shows that energy savings from replacement windows can take decades—often 40–60+ years—to offset the initial cost, which is longer than many replacements actually last. Improvements like air sealing, insulation, and storm windows often deliver better performance at a lower cost.
We’re not here to shame anyone who has replaced their windows—or plans to. Sometimes replacement makes sense. The goal is simply to help people make informed decisions, rather than assuming replacement is the only option.
And for those buying or selling historic homes—it’s worth noting: buyers often say they want “new windows,” but what they’re really looking for is comfort, efficiency, and something that feels well cared for. They think they want new windows because that's what they've been told they want & need. But is that always true?
Original windows offer something more than function:
• architectural authenticity
• craftsmanship that’s hard to replicate
• neighborhood character
• && can function just as efficiently as new windows
These are the features that make historic homes desirable in the first place.
Old doesn’t mean obsolete. Old means it was built to last.