Rule for Dehumidifier, Smart Plug and Humidity Sensor

I have recently purchased a dehumidifier that can turn on when power is supplied to it, including the resuming operation with the previous settings before power was cut to the unit. To compliment this I also have a smart plug and temperature / humidity sensor in the same room. I am keen to setup a rule to take advantage of this setup, but am unsure how best to construct a rule or choose an appropriate app. I'll also admit I am being lazy having not attempted to set this up myself :slight_smile:

If we put the rule format of triggers, actions and conditions to one side for a moment... The sequence of events I am thinking of in my head are:

Starting position:
The Relative Humidity reading for the room is in an "acceptable" range, e.g. 0-65%
The dehumidifier smart plug is off

  1. Continually assess Relative Humidity reading for the room

  2. Relative Humidity reading goes > the upper limit, e.g. 65% -> Dehumidifier Smart Plug turns on

  3. Relative Humidity reading goes < lower limit, e.g. 55% -> Dehumidifier Smart Plug turns off

  4. Wait 30 minutes (regardless of Relative Humidity reading throughout this time)

  5. Go back to step 0

I guess the bit I am unsure of is how best to achieve the combination of step 3,4 and then zero, i.e. making sure the rule doesn't trigger again during the 30 minutes if the RH% reading goes above 65%.

Any thoughts?


I don't know anything about your specific dehumidifier; I only know my own. So take these comments in that context.

What are you trying to achieve by replacing the intelligence in your dehumidifier (assuming it has some based on the fact it has settings) with external hardware and logic? My dehumidifier moves air once an hour and measures humidity over a large volume rather than one specific location in the area. Further, it runs the fan and compressor separately as it sees fit which is something you can't simulate with external control. Finally, it knows about its own duty cycle and throttles operation accordingly.

I do have mine on a ZEN15 so I can monitor its energy use and run time. The only thing I've considered for external control is some way to make changes to the settings.

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My situation is essentially the same as you are describing @HAL9000, my dehumidifier, like many I am assuming, does adjust the use of its compressor and fan as it sees fit based on the conditions it detects and the settings I choose on the unit. I guess I want a little more control over it myself, imparting my own conditions on how long it is turned on and consuming power, of any size.

Some additional detail I didn't include in my original post that may help provide some additional context would be:

The dehumidifier is currently situated in my garage.

I cannot adjust the settings on the dehumidifier through my HE, I can only do this physically using manual controls on the unit.

I intend to include some kind of cut-off time where, if the dehumidifier has been running for X minutes / hours, regardless of the RH% reading, turn it off for Y minutes. Perhaps including a warning notification of some sort if this happens....

I would also like to include logic around doors being open for an extended period of time also resulting in the dehumidifier being turned off. E.g. If any of the doors to the garage are open for more than 20 minutes turn off the dehumidifier as I must be doing something like mowing the lawn where I will often keep the main door open and so running the dehumidifier would be inefficient.

I guess the main thing I was looking for was how to achieve the logic I was after, though I do know it is always worth questioning the "why do you want to do that" as well.


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Here's one I did for two dehumidifiers using Aeotec multi sensor 6 for humidity and a couple of ST water leak sensors just in case things go badly. My dehumidifiers have a discharge pump and tube that carries them up and out through a casement window but if it freezes they get clogged and cause issues, hence the weather check. This turns them on at 50 and off at 55. This is done in webcore just because I find it easier to deal wit than RM.

And no I do not really have a dungeon :). This is just the coldest, dampest, darkest room in the basement.

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Heres a app I use, you can see upper and lower values, and has a time out if its not received a humidity update, only thing is your 30min pause

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Thanks @brad5 and @mark.cockcroft, I'll take a closer look at these in the next day or two and see how I go.

Maybe I am being overly simplistic here, but wouldn't one of the bath humidity fan apps do what you need it to?

They look for a humidity rise, and run the fan until the humidity falls. The only flaw in my theory is they don't have an anti-short cycle which is what I think you are trying to do with the 30 minute timer here.

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Quite possibly, I hadn't really looked too much at what was available, so I'll take a look at those as well, thanks.

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Thanks for the tip @neonturbo. Like I think you noticed, I've gone with the Smarter Humidity Fan App at this stage. The only part of my requirements it didn't cater for was turning off the dehumidifier based on doors being open, but the developer said he will consider it.

@brad5 and @mark.cockcroft - Just wanted to acknowledge it wasn't that I didn't like you're options, I just felt having a dedicated app took some of the work out for me. Thanks again for offering up your options.

@brad5 - If the disable switch I requested is added to the Smarter Humidity Fan App that would probably mean you could use it too, allowing you to incorporate the logic you have for weather conditions.

So just as a temporary workaround, create a virtual switch "humidifier VS". Use that VS in a rule, that if door closed, allow humidifier VS to turn on humidifier outlet. If door open, do not allow outlet to turn on.

Here is my initial thought about how I think I would handle this. I added a delay so humidifier wouldn't go off/on/off/on every time a door is opened. That logic may need a tweak, but at least it would only go on once here and not flip-flop.

Edit: in case it wasn't clear use the humidity VS in the bath fan app...

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Nice, so the concept would be the app would act on the virtual switch, then the rule is using that to actually turn on the smart plug for the dehumidifier and handle the logic of doors being open?

Which you just answered.... :slight_smile:

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I'm thinking I may need to include the doors changing state in the triggers a well, but probably need a little longer to digest the rule. I.e. if they opened while the dehumidifer was already running.

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Yea, that was just an initial thought exercise. It will definitely need some editing once you start working through scenarios.

If the app author will add the lockout switch, this will be moot. But sometimes it is interesting to experiment a bit and see how you can make it all tie together.

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I appreciate your effort, thanks for working through it, it will make it much easier for me to set it up now. It will also come in handy to provide an example of the kind of logic I would like in the app.

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I ended up splitting it into two rules and adding an extra switch to let me know when I'm in that period where the dehumidifier may be turned off soon.

The first rule is dealing with when the app adjusts the VS for the dehumidifier. I just remembered I should also include in here detecting when the smart plug device is turned on or off, to keep them in sync.

The second rule handles when any of the doors are open or closed.

I still need to incorporate the VS into the app and test it, but am happy with what I have done so far.

Actually had I known about that app I probably would have used it instead of trying to create my own!

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Just popping in here to say that 1.4.0 has the “disable on switch” functionality.

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