Whole-house Aprilaire Humidifier Works with SmartThings?

Im planning to install the Aprilaire 500 with digital controller, not sure if anyone have it already work with Smartthings?
I saw some older post that only turn on or off the humidifier, i think we can achieve with a smart power plug but not sure if its healthy to shut off the unit that way?

Welcome! I’m not sure about that unit, but I have a 360 with a smart plug that I’ve automated with SharpTools, and it works perfectly. SharpTools’ logic turns it on and off based on humidity and outside temperature.

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Thanks so sharing, so your smart plug just control the power on and off right?
Do you have that smart plug info that you can share?
Im debating betwen the manual vs digital control for Aprilaire :grinning:.
Maybe its not make that much different since its only control power on or off :sweat_smile:

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The wiring on the 500 is different from the 360. The 360 had a regular 120V plug that I connected to a smart plug and then just wired the humidity control closed. The 500 looks like it comes with a 24-volt transformer that you would need to attach to 120V. You could put a regular power cord on it and use a smart plug. The proper way to do it is to use the digital humidistat that comes with it and add the outdoor sensor to control the humidity based on outdoor temperature. This is very important, as you do not want to over-humidify and get condensation that leads to mold! I didn’t want to run the outdoor sensor, so I used SmartThings sensors and SharpTools to do the math and turn it on and off.

If you want to go the SmartThings route, you need an indoor humidity sensor, an outdoor temperature sensor, and a smart plug to turn the unit on and off. There is a cost for SharpTools; it’s $30.00 a year. There is a free version, but to do the calculations, you need the paid version. Any smart plug that is SmartThings compatible will do, same with the sensors. If you decide to go this route, I will provide the SharpTools rules you need to make it work. I will also tell you how to setup the wiring. I already had the sensors and the smart plug, so it was easy for me. You’re also probably installing this on the furnace duct, so you would need to turn on the furnace blower when it is running. I installed mine through the wall as I have electric baseboard heaters.


I do exactly the same thing with a dumb humidifier on my furnace. I put a zwave relay between the furnace and solenoid and use outside temp and indoor humidity to trigger the relay.

Sharptools setup is as follows
Rule 1: fetch the current weather from open weather. This runs every 15 minutes
Rule 2: Set a humidity target using the equation:


The equation came from using the values for my old manual huimidistat. The offset lets me add or subtract to get the humidity where I want it.

Rule 3: Comparing the humidity from an inhouse sensor to the target, I turn the humidifier relay on or off.


I’m using the same rules, except I use an Aeotec 6 multisensor that I mounted under the eave of my house. I wanted a precise calculation, and with the internet-based weather, it was off by sometimes 5 or 6 degrees.