I have a Honeywell Home thermostat running a heat pump style boiler for our hydronic in slab heating.
I would like to replace it with a ‘smart’ HA friendly thermostat.
It is battery powered but I have power close by I could run. The wires back to the outdoor unit are the classic 2 wire in black and black/white. See photos.
I’m in Australia if that is relevant.
Photos show how it is wired.
Let me know what thermostats you would recommend.
I’m not sure if your location will limit your options but anything that supports Z-Wave or Zigbee will be a great option. I use Honeywells T6 Pro Z-Wave Thermostat and it’s been super reliable for over 6 months and works exactly how you expect it to.
No specific recommendation for, but I’d recommend against the ecobee Premium thermostat I bought. While the built in smart functionality and app are nice, I ended up just integrating it via HomeKit which doesn’t allow for all the functionality.
In hindsight, I wish I’d bought a simple thermostat with basic scheduling that I could adjust via Zigbee or wifi locally without any cloud dependency, and then built whatever smarts I wanted using Home Assistant automations.
Hey mate.
I’m in the same boat as you (Australia; slab heating; no c-wire) and am curious to see how you went.
I bought a couple of the T6 Pro Z-wave thermostats on eBay a while ago, but as I only just realised they would be locked to the US Z-wave frequency, which does not overlap the AU one. I haven’t been able to find any similar thermostats here.
It seems a normal dry contact/voltage free thermostat.
You can replace it with any thermostat that has a built in relay.
If you want a WiFi one you’ll need to take mains power to that socket .
If you feel lucky (and don’t need an interface) you can use any smart relay coupled with an external temp sensor.
I have chosen a MC6 thermostat, it provides WiFi connection with Modbus/tcp exposed for native HA integration while having an embedded scheduler fo fallback, it even allows to change the schedule via modbus. Some models even offer MQTT integration.
There seems to be a newer product from the same company…
