I started noticing fog between the panes on a couple windows, not just on the inside glass, and now I’m paranoid. Is that always a seal failure or could it just be humidity? My house is older (70s build) and we do get a lot of rain. Anyone else had this and it turned out to be nothing?
If you’re seeing fog between the panes, that’s usually a busted seal. Humidity on the inside or outside glass is normal, but once it’s *between* the glass, moisture’s gotten where it shouldn’t. I had the same thing on my 60s ranch—thought it was just the rainy season, but nope, seals were shot. Annoying, but not an emergency unless you hate looking at cloudy windows. I lived with mine for a couple years before swapping them out.
Yep, fog between the panes is the classic “your seal’s toast” sign. Outside or inside condensation just means your humidity’s doing its thing, but once it gets sandwiched between the glass, there’s no easy fix. I’ve seen folks try to drill tiny holes to “let it dry out”—don’t bother, that’s just a bandaid and usually makes it look worse.
Honestly, a busted seal isn’t the end of the world unless you’re picky about how your windows look. The insulation value drops a bit, but unless you’re getting drafts or actual leaks, it’s mostly just an eyesore. I’ve had customers live with it for years, especially if it’s just a bathroom or basement window.
One thing I’d add: if you’ve got newer windows and they’re already fogging up, check if you’ve got any warranty left. Some manufacturers cover failed seals for a while, but good luck getting them to actually honor it without a fight. Otherwise, just budget for a replacement down the line—no rush unless you can’t stand cloudy glass staring at you every morning.
Honestly, a busted seal isn’t the end of the world unless you’re picky about how your windows look. The insulation value drops a bit, but unless you’re getting drafts or actual leaks, it’s mostly just an eyesore.
I hear you, but I gotta say, I’ve seen some situations where a failed seal did more than just look ugly. Had a job last winter where the fogged glass was just the start—over a couple years, moisture got in and started messing with the wood frame. Ended up with some rot and a big repair bill that could’ve been avoided if they’d swapped the sash sooner. Maybe that’s rare, but it does happen.
Curious if anyone’s actually had luck with those “defogging” companies? I’ve always been skeptical—seems like a temporary fix at best, but maybe I’m too quick to write it off. Also, has anyone noticed if certain brands or window ages are more prone to failed seals? I see it a ton in 90s vinyl windows but not as much in older wood double panes. Wondering if it’s just luck of the draw or something else going on.
Also, has anyone noticed if certain brands or window ages are more prone to failed seals?
I’ve never trusted those defogging services, honestly. It’s like putting a bandaid on a leaky pipe—the moisture always seems to creep back in. Seal failures are a pain because you lose that insulation, and if you’re heating or cooling your place, you’ll feel it on the bills. I’ve noticed older wood windows from the 70s actually hold up better than some of the 90s vinyl ones—maybe it’s the materials or just how they were built back then. Swapping out a sash isn’t cheap, but neither is ignoring it if you care about energy loss.
Funny, I actually see the opposite sometimes—those 70s wood windows can be tanks if they've been cared for, but once the glazing goes or the wood gets soft, it's game over. Vinyl from the 90s, yeah, some of those seals just don’t last. I’ve swapped out a bunch where the IGU fogs up and never really clears, even after a “repair.” If you’re seeing moisture between panes, that’s usually a dead giveaway the seal’s shot. Regular condensation on the inside or outside glass is normal, especially with big temp swings, but anything inside the double pane means trouble.
Yeah, I’ve noticed the same thing with the older wood windows—if they’re kept painted and the putty isn’t crumbling, they can outlast a lot of the newer vinyl ones. I had a set from the late 80s where the double pane started fogging up in the corners, and no amount of “defogging” kits did the trick. Curious if anyone’s tried re-glazing the IGU itself, or is it just not worth the hassle? I’ve always wondered if there’s a practical fix, or if replacement’s the only real option once that seal’s toast.
Curious if anyone’s tried re-glazing the IGU itself, or is it just not worth the hassle?
Honestly, I’ve seen a few folks try to re-glaze or “reseal” a failed IGU, but I’ve never seen it last more than a season or two. Once that seal’s gone, moisture just keeps creeping back in. The kits are more of a band-aid than a fix. At that point, I usually tell people replacement’s the only real way to go. Kind of a bummer, but those seals are factory-done for a reason. Anyone actually had luck with a DIY fix?
Tried doing a DIY reseal on one of my old double panes a few years back—scraped out the old sealant and used one of those kits. Looked good for a bit, but after the first big temperature swing, the fog came right back between the panes. I think the desiccant inside was already shot, so moisture just kept building up. In my experience, unless you’re just looking for a short-term patch, it’s not really worth it. Ended up just swapping the whole unit out the next season.
That’s the classic double-pane heartbreak, right there. Once that seal goes and you start seeing fog between the panes, it’s game over for most DIY fixes. I’ve seen a lot of folks try to reseal or even drill tiny holes to “vent” the glass—usually just buys a little time, then the moisture’s back, sometimes worse. And yeah, if the desiccant’s already soaked, it’s like trying to mop up a flood with a paper towel.
Condensation on the inside of the glass (the side facing your room) is usually just a humidity thing—long showers, boiling pasta, whatever. But if it’s between the panes, that’s your window’s way of telling you it’s done for. I get why people want to save the cash, but honestly, swapping out the IGU (insulated glass unit) is less hassle in the long run. Tried patching one in my own place a few winters ago—looked okay for a month, then it fogged up again and I was back to square one. Sometimes you just gotta let the old window go.