I’ve found the same thing with my north windows. Even with decent double glazing, I still get condensation on the sills in winter. It’s mostly down to cold surfaces meeting warm, humid air—classic spot for mold. I tried sealing everything up tighter a few years ago, but honestly, it just made the problem worse. Now I leave the trickle vents open and run a dehumidifier when it gets bad. Not perfect, but at least there’s less black mold creeping along the paint.
- Had the same issue with my 70s place—north-facing windows just seem to collect moisture no matter what.
- Tried extra weatherstripping and it backfired... air got stuffy, and the sills were even wetter.
- Ended up cracking the window open a tiny bit during the day, especially when cooking or showering. Makes a noticeable difference, though it’s not ideal in freezing temps.
- Dehumidifier helps, but I’ve found wiping down the sills every morning in winter is almost a must.
- Still not sure if there’s a perfect fix. Just seems like old houses and moldy sills go hand in hand sometimes...
North-facing windows are notorious for this. In my old bungalow, the sills would get damp all winter, no matter what I tried. I actually made things worse once by sealing everything up too tight—just like you mentioned, it got muggy and the condensation was even worse. Best thing I found was regular ventilation and using a small fan to keep air moving on the worst days. Not perfect, but it cut down on wiping and the musty smell. Sometimes you just have to accept a little bit of daily maintenance with these older places...
You nailed it about sealing things up too tight—people forget that older houses need to breathe. I had the same issue after I put in new weatherstripping everywhere. Thought I was being smart, but the humidity just built up inside, and suddenly every window was fogged up and the sills were slick every morning.
Ventilation really is underrated. A lot of folks think cracking a window in winter is wasteful, but honestly, a bit of fresh air does more for mold than any fancy gadget. I also tried one of those little dehumidifiers by the worst window, and it made a bigger dent than I expected. Not a magic fix, but less wiping.
Daily maintenance gets old, but I’d argue it’s better than ignoring it and ending up with rotted wood or black mold creeping up the trim. Sometimes you just have to accept that these old places come with quirks—kind of like owning an old car. You keep it running, but it’ll always have its “personality,” right?