I have a variable speed attic exhaust fan that is currently powered by a variable speed switch (not temp controlled tho, manually set). since it is variable, it likely will work with a dimmer too. I’ve read the threads, and fans that are not variable will apparently burn out if powered thru a dimmer, but my fan is variable.
what I would like is a smartthings compatible zwave or zigbee outlet, either installed into a outlet box or jacked into a wall outlet that will also report the temperature to smartthings. I have the smartthings multi-sensor and the iris gen2 motion sensor, and those devices report temperature to smartthings.
my goal is for the outlet to power the variable speed fan and perhaps if possible, vary the fan speed as temperature changes. it would kick on the fan, kick up the fan as temps rise, and kick it down then shut the fan off as temps drop.
Fans that are variable speed motors should never be used with a dimmer, smart or dumb. You will burn out either the fan or the switch or both. See the community FAQ (the topic title is a clickable link).
You can usually use a regular on/off switch, again smart or dumb, with a variable speed motor, but then you don’t get speed control.
If you have a single speed fan, you can use a regular on/off switch, again smart or dumb, as long as it can handle the motor load.
Always check the specifications for any switch against the fan specifications to make sure they will match.
Never use a dimmer intended to control lights with a variable speed fan. The physics are different.
To control a variable speed fan, see the fan control FAQ. It mentions Alexa in the topic title but it applies whether you are using a voice assistant or not. ( The topic title is a clickable link)
You could combine a multi-sensor (Samsung or Aeotec make ones that measure ambient temperature) with a fan speed controller (GE makes a 3-speed one). I’ll echo JDR’s “do not use a dimmer” comment. You’d have to have a set of rules or something like webCoRE to program the interaction the the sensor and controller.
I would replace the existing switch (is it a standard wall switch?) with the GE fan control switch, place a device with temperature reporting in the space, and connect both of those through this SmartApp:
I use it (or the 4-speed variant for my Hampton Bay Wink controllers) for all our ceiling fans and it works great.
Pick a sensor whose other features you can use - for instance, if the fan is noisy and you want it to turn off when you enter the attic, use a contact sensor and have it turn off when you open the attic door / hatch. If you might need to run a dehumidifier, get a temp/humidity sensor. Etc.
That’s what I do. I have a Lowe’s IRIS Motion Sensor that controls the lights due to motion, that also has a temperature sensor. (I know that the IRIS sensors aren’t available anymore, but any temperature sensor can work.) I have a GE Z-Wave Fan Controller that controls the ceiling fan in that same room. Using WebCoRE, I read the temperature from the motion sensor and then control both the speed and switch state of the fan controller - depending on time of day, temperature, Automation Override Switch state, my wife and my presence and HVAC state/mode.