Chances are, if you’re a regular reader here, you’ve heard us talk about double-paned window replacement: taking old single-paned windows out and replacing them with top-of-the-line double-paned windows. You’ll also know that the benefits of double-paned window are many: double-paned windows are great insulators, which means you lose less hot or cold air and the house stays at an even temperature — in turn, that means a lower utility bill and less wear on your HVAC system. And you probably also know that window replacement is often rebateable, meaning a hefty check from your utility company will come in the mail to offset some of the costs of the job.
But what we haven’t discussed yet is what to do when your double-paned windows are ready to be replaced themselves. We’re not talking about ones you put in last year — double-paned windows have been around for decades, and we see plenty of older homes with double-paned windows that should be replaced. Today we’ll discuss three signs that a once-great double-paned window has gone bad.
Whether your windows are fogging, condensing, or pooling water between the panes, it’s all a sign of a failed product. Sometimes windows will de-fog or dry out; sometimes they remain opaque or wet no matter how long you wait or how hot it gets outside. Either way, once a window starts to fog, it’s starting to fail.
What’s happening is pretty simple: double-paned windows are sealed to maximize insulating ability. If that seal breaks, cracks, or otherwise fails, moisture can enter between the panes. Depending on the humidity and temperature, it may fog, pool, or collect at the bottom. No matter what it does, once that seal has been broken, a lot of the window’s ability to insulate is gone.
This is especially true if your double-paned windows contained argon gas, which is commonly pumped between the panes to improve the windows’ insulation. If your windows are older they may not have argon, but most new double-paned windows come standard with the gas. We say “contained” argon gas because if your window is allowing moisture in, the argon has long since escaped.
You’ll see ads for “window de-fogging,” a practice that works questionably at best and is usually not worth the price. At its best, de-fogging removes the moisture and improves the appearance of the window. But de-fogging won’t put the argon back between the panes, and it probably won’t prevent the window from fogging up again in the future.
#2: Visible Damage
We had a client with double-paned windows and a neighbor kid with a BB gun — you can already see where this is going — and through an “accidental discharge,” the kid fired the BB gun at our clients’ window. An interesting thing occurred: the BB penetrated the first pane, bounced off the second, and rolled down between the two to rest at the bottom of the window. It was kind of cool looking, honestly—but also let out all the argon gas and really limited the windows’ insulating abilities.
Our client opted to replace the window, and that was the right call. The same is true if the window’s sealing is cracking or peeling; one of our pros will be able to tell you if your windows are not sealed right and need to be replaced (window sealing is tough to figure out for sure — the caulk around the edge of the window is not the sealing that keeps in the gas, so you’ll want a pro’s opinion).
#3: Your Windows Are More Than 20 Years Old
Even great windows can be upgraded, and if yours are a few decades old, you should experience the benefits of modern double-paned technology. Modern windows have better UV protection, better insulating technology, and are usually filled with insulating argon gas.
What’s all this mean for your old double-paned windows? Older windows — even double-paned ones — often have little or no UV protection. The sun’s ultraviolet rays will enter your home very easily through old windows, and that means big-time sunfade on furniture and carpets. And that light’s not good for people or pets either: if your cats like to sun themselves, you’d do well to make sure they have modern double-paned windows to do so in.
We talked above about the benefits of argon gas, and chances are your old windows don’t have it. Even if they were gas-filled at one point, after 15 years, they’ll only be 85% full under the best circumstances. New argon-filled windows are warrantied out for longer than that because newer windows will hold gas better. And argon isn’t the only thing that helps newer windows insulate better: they’re designed from the ground up to insulate as well as possible, and they do so much better than older windows. The glass itself is also designed to have a better R-rating than in decades past.
Whether you need to replace a broken window, upgrade older windows in otherwise good condition, or finally fix a fogging pane, we strongly recommend going with modern double-paned windows. There’s just no comparison to older window technology and we’re proud to work with homeowners to purchase and install the right window at the right price point. From UV protection to HVAC savings, we hope you let us show you the benefits of double-paned windows on your next job.