"Ended up installing a small exhaust fan with a humidity sensor instead of a timer."
That's exactly what we did too, and honestly, it's been a lifesaver. I was worried at first about messing around with wiring in our older basement, but it turned out way simpler than I expected. The humidity sensor is great—no more guessing or adjusting timers every few months. Plus, it barely makes a dent in our electric bill, which was a nice surprise. Glad to hear others are having similar luck!
We went with a humidity sensor too when we updated our storm shelter last year. Installation was straightforward, but I did notice ours kicks on randomly during heavy rainstorms... anyone else notice that? Still beats fiddling with timers though.
We installed a humidity sensor in our cellar about two years ago, and I've noticed something similar. During heavy rains or even just really damp weather, it tends to kick on more frequently. My guess is that the sensor picks up the spike in moisture levels from outside air seeping in, especially if your shelter isn't perfectly airtight (and most aren't). I initially thought ours was malfunctioning, but after checking seals and vents, everything seemed fine. Honestly, it's still preferable to manually adjusting timers or dealing with mold issues later on. One thing you might want to double-check is your vent placement—sometimes repositioning them slightly can reduce how often the sensor triggers unnecessarily.
"Honestly, it's still preferable to manually adjusting timers or dealing with mold issues later on."
Yeah, totally agree with this. We had a similar issue when we first installed our humidity sensor—every time it rained heavily, the thing would go off like crazy. At first, I was convinced we'd bought a dud and was ready to return it. But after poking around a bit, I realized our cellar door wasn't sealing as tightly as I'd thought. A quick fix with some weather stripping helped a lot.
Have you checked if your cellar door or hatch might be letting in extra moisture? Sometimes it's the smallest gaps that cause the biggest headaches. Also curious about your vent placement suggestion—did repositioning yours make a noticeable difference? I'm always looking for budget-friendly tweaks to keep things running smoothly without spending extra cash...
Had a similar issue with moisture sneaking in through our shelter's vent openings. I initially thought it was just condensation from temperature swings, but after some trial and error, realized the vents were positioned too low and close to ground level. Rainwater runoff was splashing right in during heavy storms. Ended up raising them about a foot higher and adding angled covers—made a huge difference.
Not sure if repositioning would help your setup, but might be worth checking out. Also agree on weather stripping—cheap fix that solved more headaches for me than I'd like to admit...
