I’m actually using the Wifi MQTT Relay thermostat for my central heating but only for wire connection to trigger boiler heating and as temperature sensor, the actual heating schedule/conditions is setup in NodeRed dashboard using heating node.
Interesting what you say about having the old “dumb” thermostat in parallel, hadn’t thought of that, I also left the old one on the wall as backup, just in case, but having it in parallel could make sense, especially if get house sitters
I was using sonoff Pow to “smarten” up the old boiler, but changed to Shelly 1PM (with stock firmware but MQTT enabled) as it actually fits in junction box rather than messy plug setup.
So I have node-red turn on boiler when heating comes on and so forth.
For the underfloor heating, as I understand it, temperature sensor should be under the heating elements (under/in the screed) so would need a very long wired DS18B20!
I’ve not seen any articles about successfully adding temp sensor to a Sonoff Pow R2, but that would do the job, though would have to work out where to put it as too big for back boxes – unlike the Shelly devices.
I’ve still got a Sonoff Pow running Tasmota to keep an eye on garden cabin power consumption and see if heater comes on. I could see if I manage to wire up DS18B20 to that I guess.
I’ve purchased Shelly 1 with Tasmota loaded from Flashed Firmware successfully before, not much more expensive and just makes life easier. Maybe I’ll grab a Sonoff Pow R2 from there to try out.