Dealing with foggy windows: replace the glass or just reseal?

Most times I’ve seen folks try it, the moisture creeps back in eventually.

That’s been my experience too. I tried resealing a few years ago - followed all the steps, even watched a couple YouTube “experts.” Looked good for maybe a year, then the same old fog came creeping back. If your windows are really old or the seal’s totally shot, resealing just delays the inevitable. In hindsight, wish I’d just bit the bullet and replaced the IGU sooner... less hassle in the long run.

I totally get where you’re coming from. We moved in last fall and noticed a couple windows were foggy, tried the “reseal” route just because it seemed way cheaper. Honestly, it looked better for a few months but then - yep, the haze crept right back in. At this point I kinda wish I’d just saved up and replaced the glass from the start. The temporary fix just didn’t stick for us.

Yeah, that’s the thing about resealing - on paper it sounds like a smart, affordable fix, but in practice it’s hit or miss. The seal failure usually means moisture’s already inside the IGU (insulated glass unit), and unless you fully replace that, the fog just keeps coming back. I tried one of those DIY kits last winter and got maybe six months before the haze reappeared. Frustrating, but at least it bought me some time to budget for new panes. Sometimes the upfront investment just pays off in the long run...

Yeah, I hear you on the resealing. I looked into it when my 90s-era windows started fogging up, and honestly, the mixed results kind of put me off. It’s tempting because it’s cheaper, but if the moisture’s already in there, isn’t the insulation value basically shot? I kept wondering if I was just throwing money at a temporary fix.

I ended up replacing just the glass in a couple of units instead of the whole window frame - cost more upfront, but my heating bill dropped a bit after. Maybe that’s just coincidence, but it felt like the right move. Did you notice any difference in energy bills after your panes started fogging? I always wonder how much of a hit we’re taking on efficiency with failed seals.

I get that not everyone has the budget to do a full replacement right away, though. If it buys you a year or two, maybe that’s worth it for some folks. But yeah... long-term, I think you’re right - the investment pays off, especially if you plan to stay in the house.

You’re right, once the seal’s failed and moisture’s in, the insulation factor drops a lot. I’ve seen folks try those de-fogging services, but honestly, it rarely restores the R-value. Did you notice any drafts around the frames when you swapped just the glass? Sometimes older frames leak air even after new panes.

Did you notice any drafts around the frames when you swapped just the glass? Sometimes older frames leak air even after new panes.

That’s a good point - air infiltration around the frames is easy to overlook when you’re focused on the foggy glass itself. I swapped out a couple of IGUs (insulated glass units) in my 1980s ranch last winter, and while the condensation issue disappeared, I definitely started noticing a slight draft near one window. Turned out, the old aluminum frame had some worn-out weatherstripping that wasn’t sealing properly anymore. I guess it’s a reminder that even if you fix the visible problem, there can be hidden issues lurking in the frame or sash.

About those de-fogging services, I’ve always been a bit skeptical. From what I’ve seen, they might clear up the view for a while, but you’re right about the R-value not really coming back. Once that desiccant inside the IGU is saturated, it’s pretty much game over for insulation. Still, I know a neighbor who swears by one of those services - maybe it depends on climate or window orientation?

I’m curious if anyone’s had luck with resealing just the perimeter of an existing IGU, or is it really just delaying the inevitable? My understanding is that unless you’re replacing the entire unit or at least re-bedding it in fresh sealant, moisture will keep finding its way in. But maybe there are newer products out there I haven’t heard about.

Did you end up replacing just the glass, or did you go all-in and upgrade the frames too? I’ve been debating whether to bite the bullet and go for full-frame replacements in my living room, but it’s a big investment...

You’re spot on about the hidden issues - sometimes fixing one thing just uncovers something else, especially with older windows. I really get where you’re coming from on the full-frame replacement decision. It’s a big chunk of change, but honestly, when I finally upgraded my old wood frames, I noticed a huge difference in comfort and energy bills. That said, if your frames are still decent, just swapping the IGUs and redoing the weatherstripping can buy you more time without breaking the bank. I wouldn’t trust those de-fogging services long-term either... seems like a band-aid more than a fix.

You’re spot on about the hidden issues - sometimes fixing one thing just uncovers something else, especially with older windows. I really get where you’re coming from on the full-frame replacem...

- Totally agree on the “band-aid” feel of those de-fogging services. Never met anyone who’s had long-term success with them.

- Swapping out IGUs and updating weatherstripping made a noticeable difference for me - especially in winter. Less draft, lower bills.

- Full-frame replacements are pricey, but sometimes you just have to bite the bullet if the wood is rotting or warped.

- Curious - has anyone tried triple-pane for replacements? Wondering if the extra upfront cost really pays off in energy savings.

Triple-pane is an interesting one. I've installed them in a few homes - usually for clients who are really focused on energy efficiency or have a lot of exterior noise. They do perform better in terms of insulation, but the payback period can be pretty long unless you're in a really cold climate or dealing with street noise. One thing I’ve noticed: they’re noticeably heavier, so you want to make sure your existing frames and hardware can handle the extra weight. Has anyone run into issues with window operation after upgrading to triple-pane?

Honestly, I looked into triple-pane when my living room windows started fogging up, but the price tag made my wallet cry. I get the energy savings and all, but for most of us in milder climates, it just feels like overkill. Plus, I’m not keen on my window frames sagging under the weight - my house is old enough as it is. I ended up just replacing the glass with double-pane and resealing. Not perfect, but way less drama (and cash).

That’s interesting - my place is from the 60s, and I had similar worries about the frames handling extra weight. I did some digging into the thermal benefits of triple-pane, but honestly, the ROI just didn’t add up for my area either. Double-pane seemed like a decent compromise, though I still get a bit of condensation on really cold mornings.

Did you notice any difference in noise reduction after swapping out the glass? I’ve read mixed things about whether double-pane actually helps with outside sounds, especially in older homes where the seals aren’t perfect. Also, I’m curious if anyone’s tried just resealing without full glass replacement and had good luck with that - seems like it could buy some time, but I wonder how long it really lasts.

I’m curious if anyone’s tried just resealing without full glass replacement and had good luck with that - seems like it could buy some time, but I wonder how long it really lasts.

Tried the reseal route on my 70s ranch a couple winters back. Hired a guy who “guaranteed” the seals would hold for at least five years. In reality, I maybe got two before the fog crept back in. The process was way less disruptive than replacing the glass, but honestly, it felt like a band-aid. I guess if you’re just looking to stretch things out until a bigger reno, it’s not the worst option, but I wouldn’t count on it for long-term.

On noise reduction - mixed bag for me too. I swapped to double-pane in the bedrooms facing the street, hoping for quieter nights. It helped a bit with traffic sounds, but since my frames aren’t airtight (old wood, lots of character...and drafts), it wasn’t night-and-day. If you’ve got gaps or tired weatherstripping, new glass alone won’t fix everything.

Condensation still pops up on those bitter mornings too. Seems like unless you go all-in with new frames and perfect seals, there’s always going to be some compromise in these older places.

Yeah, I hear you on the resealing feeling like a temporary patch. I tried it on my old colonial, mostly because I just didn’t want to deal with the mess and cost of full glass swaps at the time. It worked for maybe a year and a half before the same haze started creeping in again. Not sure if it was the quality of the job or just the age of everything, but it definitely wasn’t a long-term fix for me either.

I did notice that even with new panes, if your frames are drafty or warped, you’re still going to be fighting condensation and noise. Like, I spent money on fancy double-panes in the living room but skipped redoing the frames, and I still get cold air sneaking in around the edges. Has anyone here actually replaced both glass and frames at once? Wondering if that finally solves the whole fog/condensation thing or if old houses just always have their quirks no matter what you do...

That’s been my experience, too - resealing felt like putting a band-aid on a leaky boat. I actually bit the bullet last spring and did a full window and frame replacement in the kitchen. Here’s how it went: the drafts stopped, no more fogging, but wow, it wasn’t cheap. The installer warned me that old houses sometimes still get a bit of condensation just from how the walls are built, so even new windows aren’t always magic. Still, it’s way better than what I had before. If you’re dealing with warped frames anyway, replacing both at once does seem to get you closest to “problem solved,” but yeah, old houses always have some surprises...

Yeah, that lines up with what I’ve seen. Resealing was kind of a temporary fix for me - looked better for a bit, but the fog came back. Here’s what I ended up doing:

1. Checked the window frames. Mine were starting to warp, so just replacing glass didn’t seem worth it.
2. Got a couple quotes for full window + frame replacement. Not cheap, but honestly, the drafts and moisture issues were getting old.
3. After install, way less condensation, but still a little in the mornings when it’s cold out. Installer said it’s just the way these old walls breathe.

If your frames are in good shape, maybe just swapping out the glass works, but with any warping or rot, I’d say go for the whole thing. One thing I wish I’d done differently: budget a bit extra for trim and touch-ups. Those little details added up fast. Old houses are full of surprises...

- Totally get what you mean about old houses being full of surprises.
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“Those little details added up fast.”

- Resealing only worked short-term for me - condensation came back after one winter.
- Full window replacement was pricey but finally solved the drafts and warping.
- Still, I get a bit of fog on really cold mornings. Maybe it’s just old plaster walls, who knows.
- If the frame’s warped, I’d lean toward replacing the whole unit. Fixing glass alone didn’t help much in my case.

Had a similar headache with mine - tried resealing a couple of times, and it felt like a short-term band-aid. The fog was gone for a bit, but then winter rolled around and it was back, sometimes worse. I probably spent more on repeat fixes than if I’d just bit the bullet and replaced the whole window sooner.

Can’t help but agree about the frame being a big factor. In my place, the wood had swollen and shrunk so much over the years (old 1930s house, lots of character, lots of quirks), the seals just wouldn’t hold. Replacing the glass alone made zero difference, honestly. It was frustrating, because you always hope there’s a cheaper fix.

Price-wise, replacing the whole unit stung at first, but it actually made the room warmer and cut down on my heating bill. Not a magic cure for condensation, though. On really cold mornings, especially when I’ve been cooking or showering, I still get a bit of fog at the edges. I figure some of it’s just down to the house itself - old plaster, not much insulation, maybe not enough airflow. Like you said, sometimes you just can’t win against physics.

If you’re dealing with warped frames or drafty spots, I’d say replacing the whole window is worth it in the long run, even if it’s a pain up front. Still, I get wanting to try the cheaper route first - sometimes you just have to see for yourself what works. At least you know you’re not the only one chasing condensation around the house...

Can’t help but agree about the frame being a big factor. In my place, the wood had swollen and shrunk so much over the years (old 1930s house, lots of character, lots of quirks), the seals just wouldn’t hold.

That hits home for me. My last place had those classic wavy glass panes - looked great, but the frames were basically a sponge for moisture by winter. I tried every sealant under the sun, but nothing lasted more than a season or two. Ended up swapping out the whole window after a few cold snaps, and yeah, it was pricey up front but made a noticeable difference in drafts and bills.

Still get a little fog too, especially when I forget to crack a window after cooking. Sometimes you just have to accept that old houses have their own rules...

I’ve definitely wrestled with this - old frames, weird drafts, and that stubborn fog that shows up just when you think you’ve fixed it for good. My place is a 1940s brick, and the windows are original. I tried resealing them a couple years back, thinking it’d be a quick win. Pulled out the old glazing, sanded down the worst spots, put in new putty and weatherstripping. Looked nice for about six months... then another wet season hit and I was back to square one.

What tripped me up was realizing it wasn’t just the seals or glass - it’s the frame shifting every time the humidity changes. Like you said, the wood swells and shrinks so much that even the best sealant doesn’t stand a chance after a while. I even tried those moisture absorber packs between the panes as a stopgap (kind of silly in hindsight), but they didn’t do much.

Eventually I caved and replaced one window entirely - the one in our kitchen that always fogged up after cooking anything steamy. It cost more than I wanted to spend, but honestly, it made a bigger difference than all my patch jobs combined. No more icy drafts down my neck when I’m making coffee in January.

But here’s where I’m torn: I kind of miss the look of those old wavy panes, even though they were a pain to maintain. New windows are tight but just don’t have that same character... Maybe there’s some magical way to keep both charm and comfort, but I haven’t figured it out yet.

If anyone’s still trying to hold onto their originals, maybe try insulating curtains as a band-aid? Not perfect but helped with condensation on our north-facing windows for a bit.