SmartThings Community

[RELEASE] Smart Bathroom Fan


(Steve Jackson, USA, Shard 1) #21

I had the same issue. Could never figure it out. I ended up writing rules in CoRE. I have a aeon gen 5 sensor, a gocontrol contact sensor on the bathroom door and GE/Jasco switches on the light and bath fan. If the door is open, I store the humidity value sent by the aeon. When the door closes, I look for humidity rise and turn on the fan accordingly. I have other rules for the light and if house humidity is low as well as if the fan is turned on manually. CoRE will give you a lot of control if you want it.

(Robert) #22

Hi, I really like this idea but I was going to take a slightly different approach and would appreciate some feedback.

What I was going to to was to write an app (or modify this brilliant one) that monitored two different humidity sensors, one in the bathroom and one in my bedroom - which is on the same level as the bathroom - and if the difference was within a certain range then turn on the bathroom fan until they were in a threshold again. Thoughts?

I did a similar thing for a gas fireplace used to heat a room in the basement.

(Steve Jackson, USA, Shard 1) #23

I live in Northern Michigan and during the summer months I was using the humidity sensor in my living room to compare the bathroom to. It worked well, until winter came. I have forced air heat with a vent in the bathroom. The forced air dries out the bathroom to the point that the humidity can be 15-20% lower than the living room. That’s when I started using the bathroom humidity sensor as the humidity setpoint the moment the door is closed. Actually, I continually update a global variable and then use that if the door closes. I’ll run the fan until I think get within 5% of the setpoint or 60 minutes, whichever comes first. The fan will also turn off when the door is opened, regardless of humidity, if the house humidifier program is calling for more humidity and the humidifier outlet is on.

With the manual override for my wife, it takes me 3 pistons. It could probably be done with fewer but it works so I never messed with it. Too many other things to fix. I’m getting enough devices and rules that I’m starting to see some regression errors with new rules interfering with old ones. It doesn’t help that my automatons are constantly getting more complicated too. Once the bug bites you there is always another automation. LOL

When we move this year, it will be nice to start over clean. I will probably even invest in a V2 hub at that time. I know I can do better automatons more cleanly now that I have a better idea of what I like things to do.

If you would like copies of my humidity piston let me know, I would be happy to share them.

(Robert) #24

I’m originally from Mid-Michigan so I know what you mean. I’d love to have it, thanks

I purchased a V2 hub when it came out and have trouble now with my Zigbee bulbs - not sure if you have any but something to consider.

(Steve Jackson, USA, Shard 1) #25

I have no problems with much of anything. I only have 5 zigbee bulbs. The other 50 or so devices are z-wave. 3 of the bulbs, ge, are within 15ft of my hub and the other 2, cree, are probably 40+ feet away. My z-Wave mesh is strong. Zigbee, not so much so I’m surprised I don’t have issues. I have had only a couple occasions where the Cree have acted up but I left them alone, they always fix themselves in a day or so. Any issue is very rare though. I have had great luck with the v1 hub so am scared when I read the issues with the v2. I guess I’ll see what things look like when I set up the new place down South. Anyway, here are the pistons.

This piston stores the current humidity level in the bathroom in a global variable if the door is open and the fan is not on removing humidity. I have a sensor on the door. It works great for making due the light stays on too without having to try and find showers, etc.

This one turns on the fan if humidity is high, 5% above setpoint. It will turn it off if we are close to the living room humidity level, or if the house needs More humidity or it times out at 60 minutes.

This one is used if my wife is cleaning the bathroom and uses the fan to exhaust the fumes. It ignores humidity and will run for 60min if not turned back off manually.

Make sure to click on the pictures. A couple of the pistons are longer than what is showing.

The humidifier program I’m using to add humidity to the house is called smart humidity control. It takes the outdoor temperature and indoor humidity into consideration (again Michigan and wet Windows if humidity is too high when temps are too cold) and then turns on an outlet. It works quite well. The guy that wrote it was kind enough to share the code.

Any questions just ask.

(Michael) #26

Is this version by BTK dead? It doesn’t look to be updated in 10 months and I keep getting an error when trying to run it from ST. I tried both git hub and just using (copy/pasting) the raw code. When I run the simulator I get this error:

org.springframework.orm.hibernate3.HibernateOptimisticLockingFailureException: Object of class [] with identifier [0d3e816e-dbab-45d9-af57-e1a0eecb594d]: optimistic locking failed; nested exception is org.hibernate.StaleObjectStateException: Row was updated or deleted by another transaction (or unsaved-value mapping was incorrect): []

I am completely new to ST so not sure where or how to troubleshoot. I’m curious if this smart app still works for others. I have a GE smart switch on my fan and a Centralite 3-Series Zigbee Temperature/Humidity Sensor - Model 3310 (

Any suggestions?


I am having some issues with this SmartApp. I have an aeon labs multisensor 6 setup in my bathroom and use this as my humidity sensor. When I look at the logs of the switch I can see that the app turns it on, then 4 minutes later seems to turn the switch off again. The sensor is working on batteries so check in every 4 mins with the hub and have seen that it only reports the humidity if the humidity has changed. So all I can think is that after 4 mins, the sensor is not reporting an updated humidity and for some reason the app then turns the switch off, although the shower is still on and the room is very humid. Has anyone else had a similar issue? Have I got any of the settings wrong?
Also, where can I see what the smartapp thinks is my average 24hr humidity?

(Mark) #28

I think @btk hasn’t been around in a while. I was trying to get another one of his smartapps working a few months ago (Holmes WeMo smart Humidifier), wasn’t able to and couldn’t get a response from him on the forum.

(Michael Orbon) #29

Nice logic!
Good game theory.


You need to edit smartapp and turn on OAth.