I get where you’re coming from, but I’ve actually had pretty different results after swapping out my old fan for a Panasonic with a built-in humidity sensor. My bathroom’s on the small side and the duct run is a mess—two sharp bends, maybe 12 feet total—but after I upgraded, the fog on the mirror and windows disappeared almost entirely, even after long showers. I did have to run new ducting and insulate it since condensation was an issue in winter. Honestly, I think the fan’s quality and the way it’s installed matter just as much as CFM ratings or coatings. The coatings always seemed like a band-aid to me.
Honestly, I think the fan’s quality and the way it’s installed matter just as much as CFM ratings or coatings. The coatings always seemed like a band-aid to me.
That’s interesting—my bathroom fan is probably older than I am, and I’ve been blaming the fog on “bad airflow” for months. Never really thought about the install itself being part of the problem, beyond just CFM numbers. Coatings seemed like a shortcut to me too, but now I’m wondering if I should just bite the bullet and upgrade the whole fan/duct setup. Was it a nightmare running new ducting? My attic is basically a crawlspace…
Running new ducting in a crawlspace attic isn’t the most fun I’ve had, but it wasn’t as bad as I expected. If you can manage to get up there with a headlamp and some patience, it’s doable. I used insulated flex duct to help with condensation and noise. The trickiest part was sealing up around the vent cap at the roof—definitely wear old clothes because fiberglass insulation gets everywhere. Upgrading the fan itself made a bigger difference than I thought, too. My bathroom clears out steam way faster now, and the windows don’t fog nearly as much. If you can swing it, it’s worth the hassle.
- Upgrading the fan made a huge difference for me too—didn’t realize how much steam it was missing before.
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— yeah, that’s always a pain. I ended up using a ton of foil tape and still worry about leaks.“The trickiest part was sealing up around the vent cap at the roof”
- Curious, did you notice any drafts after changing the ducting? My crawlspace attic is drafty and I’m worried about cold air sneaking in through the new vents.
- Upgrading the fan was a game changer for me, too. My old one sounded like a jet engine and barely moved any air—finally swapped it out after a fogged-up mirror convinced me something had to change.
- Sealing around the vent cap… ugh, that’s always a little stressful. I used foil tape and then went overboard with some exterior caulk. Still, every time there’s a heavy rain, I get paranoid and check the attic for leaks. Not sure there’s ever a “perfect” seal up there.
- About drafts: after I changed the ducting, I did notice a bit more airflow in winter. Nothing major, but enough to make me double-check the damper on the vent hood. Turns out mine wasn’t closing all the way—fixed that with a new spring-loaded one, which helped a lot. If your attic’s already drafty, maybe worth checking if your vent has a proper backdraft damper (some of the cheap ones are basically useless).
- Foggy windows are still kind of an issue for me when it’s super cold out. I think some condensation is just normal if you’ve got single-pane or older windows, especially after showers or when cooking. I’ve tried running the fan longer and keeping doors cracked, but sometimes it’s just a losing battle in January.
- One weird thing: after upgrading my fan and sealing everything up, I started noticing more dust in the bathroom. Not sure if it’s pulling in from somewhere else or just stirring things up differently? Anyone else run into that?
- Overall, I’d say don’t stress too much if you see some fog now and then—unless you’re getting puddles or mold, it’s probably within “normal” for an older house. Just keep an eye on those seals and maybe toss an extra towel under the window if it gets bad.
Funny how fixing one problem always seems to create another minor headache… but hey, at least it keeps things interesting!
Foggy windows are still kind of an issue for me when it’s super cold out. I think some condensation is just normal if you’ve got single-pane or older windows, especially after showers or when cooking. I’ve tried running the fan longer and keeping doors cracked, but sometimes it’s just a losing battle in January.
That’s definitely a familiar scenario, especially with single-pane glass. I’ve worked on a lot of homes from the 60s and 70s, and honestly, even with good ventilation, those old windows just can’t keep up with the temperature swings. The inside pane gets cold, moisture from the air condenses, and you get that fog (sometimes even frost if it’s really brutal out). Double-panes help, but if the seal fails you’ll get fog between the panes, which is a whole other headache.
One thing I’ve noticed after a window upgrade is that the condensation shifts—less on the glass, but sometimes more around the frame if the insulation isn’t perfect. I had a client who replaced all their windows but skipped air-sealing around the trim. Next winter, water was dripping down the wall. Turned out the humid air was sneaking in through tiny gaps and hitting cold framing. It’s wild how a tiny detail like a missed bead of caulk can undo all the fancy glass.
On the fan/dust thing: after tightening up ventilation in my own place, I got more dust too. I think when you boost airflow and seal leaks, you sometimes create negative pressure, which can pull air (and dust) from odd places—like the attic or even wall cavities. I had to add a weatherstrip to the bathroom door because it was actually drawing air from the hallway every time the fan kicked on.
As for “normal”—some fog on single-pane or older double-pane windows in winter is pretty much par for the course, especially after hot showers. If it’s just a bit of mist that clears up in an hour or so, I wouldn’t lose sleep over it. But if you’re seeing water pooling or mold, that’s worth digging into. Sometimes just cracking a window for five minutes after a shower does more than running the fan for half an hour.
Funny how you fix one thing and another pops up. I guess that’s just old houses for you… always something to tinker with.
Yeah, I hear you. Single-pane windows in winter are just a pain. I get a little fog on mine every time we cook or shower, especially if it’s below freezing outside. I’ve tried the usual—running the bathroom fan, leaving the door open, even putting a towel on the sill when it gets bad. It helps a bit but never totally fixes it.
One thing that made a difference for me was getting a cheap humidity gauge. Turns out my house was way more humid than I thought in winter. Cutting back on humidifiers and cracking a window for a few minutes after showers helped more than running the fan nonstop.
I agree about window upgrades not being a magic fix either. My neighbor swapped all his old windows for double-pane and still had condensation, just in different spots like you said—mostly around the edges now. Seems like unless you go all-in with insulation and sealing, there’s always going to be something.
Honestly, as long as it’s not puddling or growing mold, I just wipe it down and move on. Old houses are stubborn that way...
That’s honestly a super practical approach. I get the urge to want everything perfect, but old houses just have their quirks. Humidity sneaks up on you, and even the best windows won’t fix it all if the rest of the house is drafty or under-insulated. I’ve found that tweaking small habits—like you said, opening a window briefly—makes a bigger dent than obsessing over hardware. Sometimes it’s just about managing expectations and embracing a little imperfection.
Funny thing—I've seen folks spend a fortune on fancy windows, only to still get fog in the mornings. If your house is older, it's almost impossible to eliminate all condensation, especially in weird weather. I always tell people, a little fog on the inside during cold snaps is normal. Major moisture between panes, though... that's usually a busted seal and a different story. Sometimes, chasing perfection just means chasing your tail.
That’s pretty much my experience too. I live in a 1950s ranch and no matter how many times I reseal or upgrade, there’s always a bit of fog when it gets chilly. Like you said, unless there’s water trapped between panes, it’s just part of the deal. Chasing that “perfect” window is like trying to find a quiet spot at Thanksgiving dinner… probably not happening.