Physical Interface for a Virtual Thermostat

With the recent outages for Alexa remote2 and the authentication issues facing the home assistant app, I have been investigating a physical interface for my 3 virtual thermostats which control room fans and heaters via smart plugs using room temperature sensors.

First thing that came to mind was out of Inovelli’s playbook, a “smart bulb mode” but for thermostats. I was planning on getting a thermostat that works with Z2M or ZJS (been eyeing the Centralite Pearl Thermostats) and then linking the core functions to my virtual thermostat, or perhaps just bypassing the virtual thermostat altogether. That way to the end user it just looks like the thermostat is actually wired into something when in reality it isn’t and is only getting power. I am not too worried about the control part of that equation, I am more worried about how to get power to the unit as I am betting they do not take mains power. Also depending on the unit, I am not sure how it will handle nothing actually being wired into it, for all I know it actually won’t function without the output wires connected to something.

Has anyone run into a situation like this at all or investigated anything like that?

Also if anyone has any other ideas for a physical interface, I would appreciate it.

Usually the hardware primary concern is with powering itself rather than the switching. Yes, several of these derive power via the circuits they are switching but most can be more traditionally powered directly with 24v AC too. Nest were very ‘intelligent’ in deriving power from the ancillary circuits but can be ‘brute forced’ too. Most work fine without the connected loads. I use virtual drivers for various thermostats although not the Centralite model you mentioned.

One consideration is does the virtual driver implement smarts, for example cycle delays, lockouts and setpoint enforcement for cooling being higher than heating. In my case I wanted the virtual driver to be totally dumb with the smarts being applied by the hardware.

We will see, I have one of those centralite thermostats coming and it appears to have a battery backup, so worst case I can test with that. If it works, I could down the road of getting a 24v ac transformer to step down the mains voltage and install a box in the wall to house it.

I have this as my virtual thermostats now:

It’s really good, just unfortunate that you need to mess with yaml to set it up.

We will see what happens when the new thermostat arrives, I’m not sure if the logic should be done on the device (if it can be) and I just feed in inputs and handle outputs, or done via NR, or done via virtual thermostat. I am still rolling around the pros and cons of each in my head.