🚿 Bathroom Humidity Exhaust Fan

@Blacky yes please :slight_smile:

Just developing now and I will do a quick test.

Edit: Check you messages, all done

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Im using a Ducobox with a Open Air Mini including a humidity sensor. How can I use/change this blueprint so I can have the fan idle on 30%, set the speed to 100% when somebody is using the shower and after the humidity reaches the desired level set the fan speed to 30% (for example)?

I don’t use Ducobox but it looks like a realy nice product. The “Fan Speed - Switch Off Option” was developed for the Itho box and I think this is a similar product.

With your Ducobox if you have an entity in HA that set the speed to 100% then you would put this into the “Fan Switch”. Then if you have an entity that set the speed to 30% then you would put that into the “Fan Speed - Switch Off Option” and enable this option. Because I don’t use or have a Ducobox I am not sure if it has these entities in HA. If it doesn’t have them then you could create them probably like a fan speed switch where ON = 100% and OFF = 30%.

PS: Just make sure if it is the one fan that you can’t turn 100% ON at the same time as 30%, so it would have some type of interlock that will only allow one of the two entities to be ON at any given time.

Blacky :smiley:

I will give this a try. thank you

New update 1.6

:warning: You will need to do something in this update. See below “Clear Home Assistant Restart YAML”.

New Features :new:

  • Home Assistant restart built in, no more selection required. You will need to clear the old HA restart yaml, see blow. The restart feature now has a lot of extra features built in that will check your automation for you.
  • By-pass upgrade. There are more option to choose from.
  • By-pass auto OFF feature. You can now set the by-pass to automatically switch off. It can also be used as a timer to turn the fan ON and then OFF if you have chosen to use “Enable the By-pass - Turn fan ON”.
  • It now can also work with my just released new blueprint :infinity: Sensor Light Add On - Media & Movie - House Alarm - Fire Alarm + More. If you have smoke detectors connected to HA, the blueprint add on can now disable this blueprint automations and turn your exhaust fan ON including lights when the smoke detector is activated. It is all done through the by-pass hence the by-pass update.

:construction_worker_man: Clear Home Assistant Restart YAML :construction_worker_woman:

To clear your HA restart yaml please follow these steps. This is only required if you are updating the blueprint.

1 - Update you blueprint and open your automations.

2 - Click on the 3 dots top right.

3 - We are looking for the code , “ha_restart” and “include_ha_restart” as shown below. If you don’t see this code then you are all good, no need to do anything further.

4 - If you see the code then delete it, click save then the 3 dots and “edit in visual editor”.

5 - Your all done.

If you like this blueprint? Consider hitting the :heart: button in the top post :+1:

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Blacky :grinning:

Thank you for this awesome blueprint!

My exhaust fan runs for 10 minutes per activation / button press. Is there some way to reactivate the blueprint after 10 minutes if the humidity is still to high, so the exhaust fan starts again?


Hi Robin,

Your welcome and thanks for your kind words :smiling_face_with_three_hearts:

Yes in some situations. If your humidity is staying high then best to run the fan for longer, so extend your time delay. There is a “Maximum Humidity” setting but it must cross over from a lower setting to above you setting, then the fan will turn ON automatically.

You can also manually do this with the by-pass. How to set this up;

  1. Select “1 - Enable the By-pass - Turn fan ON”
  2. Create a by-pass, this is in the FAQ if you need it and enter it in.
  3. Select “When you turn the by-pass off - Do not run the automation and turn the fan off instantly”
  4. Select “Enable the by-pass auto off option”
  5. Set your “By-pass Auto OFF - Time Delay”

Now when your turn the by-pass ON it will turn the fan ON and then OFF in your set “Time Delay”. It is a manual operation though.

Hope this helps

Blacky :smiley:

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Thank you for your help!

So if I understand correctly, there is no way to automatically reactivate the fan after 10 minutes if the humidity stays high?


The blueprint works off and Humidity Derivative Sensor. It a bit tricky to get your head around. I will explain.

Say humidity is 75% and it rises to 90% the Humidity Derivative Sensor will see this and knows you are having a shower. Fan ON. If the humidity stays High then the Humidity Derivative Sensor just stays at 0% and the fan stays ON. When the humidity drops the Humidity Derivative Sensor then knows you have finished by going to a negative value. It will then start the time delay set by you. Make sure you monitor this so you know the humidity drops before turning OFF the fan and adjust the time delay as required. So your humidity should drop. If this doesn’t happen then you have a “Safe Guard - Maximum Run Time” that you can adjust so the fan will turn OFF and not just run forever.

So if you set it up correctly the humidity should drop before the fan turns off.

If it drops but not enough to turn the fan ON again when you are having back to back showers then the “Maximum Humidity Option” will turn the fan ON. Example the humidity drops to 80% enough to start the time delay but when it rises to 95% it is not enough for the Humidity Derivative Sensor % but is triggered ON because the humidity crosses over Maximum Humidity and turns the automation ON again. You dont know this because the fan never turned OFF it just stays ON until the humidity drops again. This is were your question is. So the humidity should at this point be lower than your Maximum Humidity Option and if it increases above your setting then it will turn the fan ON again and run the automation.

To answer your question it is yes but no, the automation will not turn the fan ON again if the humidity stays high for x amount of time, but this should never happen if it is set up correctly and you have a fan that is adequate for a shower exhaust.

My recommendation would be to read the settings FAQ Click Here. Monitor your showers and adjust your setting to you get it right. I have included my settings in the documentation and this should be very close to making it work but ever site is different. I does take some time to get the settings correct but once you get it, the automation should work perfectly. Sensor location is critical to making it work as well.

Hope this helps you

Blacky :smiley:

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Thank you so much for your time and explanation! It’s a bit more clear to me now. I will monitor the behaviour of the blueprint and humidity for the upcoming days and see if I can finetune it. Thanks a lot!

@Blacky first of all thanks for a great blueprint, it works well, but Visual Studio says there is Deprecation’s in your script.


Hi Andy, Thanks for the heads up I realy do appreciate it :+1:

I did see this on the latest Visual Studio pop in this update. There is no problem as I know how to fix it and it the same in all my blueprints. I didn’t want to push out the fix ASAP as if you dont have the latest HA it will probably break the blueprint. HA have said that they are giving a 12 month period now before they turn OFF breaking changes. By then I will resolve this probably around the 3 to 6 month mark so everyone will have time to update HA and everyone will have time to also update this blueprint before it stops working :wink:.

Again, thanks for the heads up, it is realy nice to know of these things ASAP and sometimes I miss them.

Blacky :smiley:

np, i’m just starting to understand blueprint’s so I can do some of my own in time.


Well, this is different. For the last 3 years, I have been controlling the bathroom humidity in a crude way, through node-red. I just now happened on this post and will have to read through it. I thought I was the only one interested in this. I am very happy someone else is talking about this subject. Below are my iterations in node-red (the uneducated way, lol).

Yeah, this is one blueprint I realy love and it works well. Since using it all the mould issues in the bathroom are gone. In the past, someone in family would forget to turn the fan ON including me, now it never forgets and we use to turn the fan OFF when we would leave the bathroom, now it runs for the correct amount of time before turning OFF.

Blacky :smiley:

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Bathroom Dimmer turned off triggered by automation Bathroom Humidity Exhaust Fan triggered by numeric state of Bathroom De-Humifier

Not sure why the light was turned off. I don’t see where I set it to do that? Is this not configurable? Thanks.


Hi Richard

Could you please provide us your YAML of the automation? This YAML code are the settings you have selected in the automation so I can help. To do this go into your automation, top right 3 dots, Edit in YAML, copy all the code, come back to the forum and in your reply at the top tool bar click on “</>” and paste code in there.

Then I will be able to see what is happening with your automation.

Blacky :smiley:

New update 1.7

Bugs Fixes :bug:

  • Fixed an error in light transition as shown below. This was probably when you are using zigbee2mqtt.
Transition value 0 is not valid.

If you like this blueprint? Consider hitting the :heart: button in the top post :+1:

If you like my blueprints, and would like to show your support or just say thank you? Click Here :smiling_face_with_three_hearts:


Blacky :grinning:

Hi @Blacky,

First of all what a good Blueprint just what I was looking for. Until yesterday my extractor fan was controlled by my plc, because a remote IO station has broken (which has a long delivery time), I came across this Blueprint which does almost exactly the same as what I programmed in the plc. Only when I took a shower this morning did I notice that the fan wouldn’t come on and I turned it on manually to check the logs later. Now I suspect I did something wrong somewhere because I get the following error every time the automation is triggered.

Error log:

Logger: homeassistant.components.automation.hvac_bathroom_humidity_exhaust_fan
Source: components/automation/__init__.py:608
Integration: Automation (documentation, issues)
First occurred: 11:06:59 (6 occurrences)
Last logged: 12:20:26
Error rendering variables: UndefinedError: 'dict object' has no attribute 'entity_id'

Config in :point_right: /config/automations.yaml:

- id: '1692464664570'
  alias: 'HVAC: Bathroom Humidity Exhaust Fan'
  description: ''
    path: Blackshome/bathroom-humidity-exhaust-fan.yaml
      trigger: sensor.bathroom_humidity_derivative
        - fan.fan_bathroom_on_off
      bathroom_humidity_sensor: sensor.temperature_and_humidity_sensor_bathroom_humidity
      time_delay: 15
      include_max_humidity: maximum_humidity_disabled
      time_out: 45
      falling_humidity: -1

I must have done something stupid but I can’t see it at the moment :sweat_smile: