The fan does run longer than I’d probably leave it on, especially in winter when the bathroom gets super steamy. But I haven’t seen any mold since, so I guess that’s worth the tradeoff for me.
That’s the thing—mold is a nightmare to deal with once it starts, so I’d rather have a fan that overruns than risk it. Did you notice if the humidity sensor is sensitive enough? Some of mine seem to kick on if someone just takes a hot shower for five minutes, but others barely react unless it’s a sauna in there. Also, did you have to mess with attic access or was everything reachable from below? That’s always my least favorite part... crawling around up there with insulation everywhere.
Yeah, attic access is always a pain—last time I had to move a bunch of old insulation just to get to the vent line, and I was itchy for days. I’ve noticed those humidity sensors can be hit or miss too. One of mine basically ignores anything under a full-on steam bath, but another kicks on if you so much as run hot water for a minute. Did you end up adjusting the sensitivity, or just leave it as-is? I’ve heard some folks swap out the sensors for better ones, but I haven’t tried that yet.
Humidity Sensors Aren’t Always Worth the Hassle
I’ll be honest, I’ve stopped bothering with those humidity sensors in most of my units. Here’s why:
- The inconsistency you mentioned is exactly what drove me nuts. Some sensors are hypersensitive, others barely register a shower. Even after fiddling with the sensitivity dials, it’s a guessing game.
- Tenants either complain the fan runs too much or not enough. Either way, I end up fielding calls about it.
- Swapping out for “better” sensors hasn’t made a big difference in my experience. I tried a pricier Leviton model in one place—still got weird results depending on how steamy the bathroom got.
What’s worked better for me:
- Standard timer switches. Set it for 20–30 minutes post-shower and you’re done. Less to go wrong, and tenants get used to it pretty quickly.
- If you really want automation, motion sensors tied to the fan have been more reliable than humidity ones. At least you know the fan will run when someone’s in there.
I get why people like the idea of humidity sensors—hands-off and all that—but in practice, they’re just another thing to troubleshoot. Unless you’re super particular about energy savings or have a high-end system, I’d keep it simple.
And yeah, attic work is always miserable. Last time I was up there, I found an old wasp nest wedged behind some insulation... nearly jumped out of my skin. Give me a straightforward switch any day over crawling around up there again.
Timer switches are the way to go, honestly. I’ve swapped out a bunch of humidity sensors after tenants kept calling about the fan running at weird times or not at all. With a timer, you just set it for 20-30 minutes after a shower and forget it—no more guessing games. If you want to get fancy, motion sensors work too, but I’ve found timers are less hassle in the long run. Just make sure you pick one with a decent range of settings, not those cheap ones that only do 5 or 10 minutes. Keeps things simple and reliable.
I get what you mean about timers being more reliable. I’ve had a humidity sensor in my bathroom for a couple years and it’s honestly been a mixed bag. Sometimes it kicks the fan on when I’m just running hot water for the sink, which feels like overkill, and other times it doesn’t seem to notice a steamy shower at all.
I do worry a bit about timers, though—what if someone forgets to set it after a shower? Or is that just me being overly cautious? I guess with guests or kids, I’m always thinking about the “what ifs.”
Just make sure you pick one with a decent range of settings, not those cheap ones that only do 5 or 10 minutes.
That’s a good point. I’ve seen some with like 60-minute options, but then I wonder if people will just leave it running forever and waste energy. Has anyone tried the combo switches that have both humidity and timer settings? Curious if that’s just overcomplicating things or actually helpful.
