Virtual Thermostat Device Type and smartapp for Underfloor heating

I have searched and searched for something that seems obvious to me but I cannot for the life of me find the appropriate solution.

I have a wet underfloor system with 240 Volt actuators which I have connected to fibaro switches and I have fibaro motion sensors peppered throughout the house - the fibaro movement sensors are also temperature sensors.

There is a Smartapp for a Virtual Thermostat to connect the temp sensors and switches but there seems to be no solution to emulate a standard thermostat like a Nest but using a virtual device type (so the setpoint can be changed by Alexa).


  1. Create a simple device type that is virtual that can display and increment heating setpoints
  2. and then use a smartapp to activate the underfloor heating zones via the switches and sensors

Can someone help with ideas?


is it slab heating, or low-mass ? Underfloor is typically slow, and you don’t want to cycle it frequently.

Besides, ST is cloud-only for your proposed purpose. Requiring internet and cloud operation for your local temperature control is frankly stupid. There are hundreds of anecdotes that describe lighting control failures and unintended operation. Will you design control-fault-tolerance into your heating system? Is freezing not a concern?

Just my opinion - don’t do it virtually.

Hi Eric


The last time it went below freezing here was about 80 years ago! The relays are wired like a switch to existing analogue thermostats. i.e. it is retrofitted

The hot water is supplied by a heatpump running at 40c

I have had ST installed since it came out in the UK and I have not had an instance where it has gone down for more than an hour - I consider it pretty stable.

The best I can come up with at the moment is this guy:



But these are work in progress and a lot of logic is missing.

Any help or ideas would be greatly appreciated.



Hi, did you ever find answer to this?
Also in the same quest for this, except im having radiant underfloor heating, and not waterheated.
Still same principle as they’re controlled by fibaro relays (manually).