Recommendations for humidity sensor (for bath fan)

I’m in the market for a reliable, semi-accurate humidity sensor to automate a bath fan (in the US). I’ve searched and while there are several threads about this, most of the devices are no longer available (including the Everspring and the Centralite ones). Does anyone have any others to recommend? Or know where to find those?

Being able to permanently power it would be ideal as well, though not a deal breaker. On that end, does anyone successfully use rechargeable CR2 batteries? My recessed door sensors eat them.

Anyone have experience with the Aeotec Multisensor 6? Does it update reasonably fast?

I use a Zooz zse40 in one bathroom and an Iris 3rd gen motion sensor (IL071?) in another. The zooz is nice because you can adjust the humidity sensitivity.

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I use the new gen 3 motion sensor from Iris like Jimmy. They can be found on eBay pretty cheap for used ones. New one are hard to find, but they’re out there.

I use the Xiaomi humidity sensors in both bathrooms. For the last year they have been fast to update and accurate as far as I can tell. Haven’t gone offline either. Price is right as well.

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The most reliable humidity sensor I’ve found is by a user on these forums who makes his own, and shares them with the community when he can. They are USB powered, you also get temp, luminance and pressure sensors on-board, and they work as Zigbee repeaters! Cheaper and better than anything commercially available.

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Zooz 4in1. Hardwire that baby and never have to worry about changing the battery. Humidity sensing works great!

I also use Xiaomi but recommend Zooz for reliability.

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@Alwas. Thanks for the kind word. I really appreciate your support.

I have a few modules available to share in case anyone need it. As repeater, it is one of a Zigbee Repeater that would work with Xiaomi devices.

Here’s a listing for some used gen 3 Iris devices: (~$15, or make an offer!)

https://www.ebay.com/itm/Iris-Motion-Sensor-IL07-3rd-Generation-Works-with-SmartThings-Zigbee/153437876092?_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20160908105057%26meid%3D6bed0d2ee8934c418813fdba0bfec72b%26pid%3D100675%26rk%3D1%26rkt%3D15%26sd%3D153437876092%26itm%3D153437876092&_trksid=p2481888.c100675.m4236&_trkparms=pageci%3A82700540-8273-11e9-b060-74dbd1806431|parentrq%3A062e41b916b0ab4573def10cfff911ea|iid%3A1

I installed a Zooz 4-in-1 in my master bath about a month ago. I adjusted the sensitivity to +/- 2% RH and it works great. I set it up using a DTH that was recommended from the Zooz support website. One thing you need to know is that it will check the humidity every 3 minutes. So if you are expecting something faster than 3 minutes you may be disappointed. The 3 minute response time for me works OK…I have it set up to turn on the fan upon a rise in RH above 65% and turn it off upon a drop in RH below 65%.

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+1 on the Xiaomi (Aqara)

I noticed eh IRIS reports humidty every 3 minutes, is the Zooz any faster?

In my experience, using the DTH that I am, the humidity on the Zooz 4 in 1 updates about every 3 minutes, if the humidity is changed beyond a trigger point, that I have set at 1% humidity. I believe this is so to extend the battery life.

This works for me in controlling the bathroom fan based on a humidity setpoint.

Just wanted to check on this topic again as I would like to trigger a bath fan if the humidity changes.

I’d like a sensor that…

  • humidity detected quickly. 1 min for example.
  • look at historical change of humidity so less false alarms, I live in a humid climate.

Any thoughts? I read the Aqara might fit these needs but not sure if their hub is needed or if it has historical data that can be worked with.

Thanks!

A recent review on Amazon for the Aqara Temp/Humidity Sensor indicates humidity does not update frequently enough to use with a bathroom for for a Home Assistant user. I would expect ST to have the same frequency.

I have been looking for something similar but based on feedback in other threads, it still sounds like there aren’t many good solutions for using ST sensors that aren’t motion sensors able to detect motion in the shower (posssibly in combination with some other sensors, such as temp)

I have seen some non-smart switches with humidity sensors that can accomplish this, but my switch for my bathroom fan is about 8 ft away from my shower and think it may have some performance sacrifices at that distance and haven’t wanted to dig into buying it and wiring it up to test.

Not sure exactly what use case you had in mind, but the new device class of MM wave sensors is frequently used for detecting that a person is in the bath/shower even through a glass door.

Originally most “motion sensors” used with home automation systems were actually PIR (passive infrared) sensors, detecting small changes in heat as it moved across the lens. Not only could they not detect through glass, they were particularly unhelpful in bathrooms because of the rising heat and the inability to realize that there was still someone in the bathtub or the shower.

In contrast, MM wave sensors are actually detecting motion, and they can detect even “very fine” motion like a person breathing. So for the last six months or so, we have been seeing more and more people adopting this device class for many of the bathroom and bedroom use cases.

In many situations, this eliminates the need for a humidity sensor all together, since in the past people frequently used rising humidity as a way to proxy for a person being in the shower. Now that is no longer needed: you can actually tell whether a person is there or not.

Here’s the community FAQ if you’re interested:

Best mmWave Sensor to Use with ST? (human presence sensor/occupancy sensor)

Of course, humidity sensors still have value for environmental controls, like greenhouses, musical instrument storage, comfort in dry climates, etc.

So it all comes down to the details of why you wanted that information. :sunglasses: :bath:

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In my master bath, having a motion sensor wouldn’t be a big deal, but many non-technical people might confuse a motion sensor as a camera device and feel uneasy, so having a motion sensor in any bath other than my master is something I would prefer not to have to explain at risk of my guests feeling uncomfortable…

Many of the MMwave sensors intentionally don’t look like cameras. That’s also part of the point. They are used in a lot of situations where privacy is required, like hospitals. Take a look at the link and you’ll see some of the options currently available, but of course it’s up to you. Choice is good. :sunglasses:

Best mmWave Sensor to Use with ST? (human presence sensor/occupancy sensor)

btw, not only can the MMwave sensors detect through glass, they can detect through many opaque materials, even a thin plaster wall or a box cover. So you can hide them completely if you choose to. (I have one at my house sitting on a shelf inside a basket, and it works fine.) I’m not sure if that’s more or less creepy, though. :ghost:

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