Control Shelly Thermostat with Google Home

[rjwill10]

I recently fitted a new Boiler and decided to utilise an unused shelly 1pm and bought a h&t gen 3 to create a smart thermostat. 

In the Shelly Cloud/App I've created a Thermostat, which seems to be similar to a scene. I've configured it to turn on/off the shelly 1pm depending on the set base temperature. 

I want to be able to turn on the virtual thermostat when needed, I don't, for example want to leave it running all day or night. I just want to turn the heating on when I need it and off when I don't.

This is possible via the shelly app, but the Thermostat isn't visible in Google home. I can toggle the shelly 1pm on/off, but not the thermostat. 

Is if feasible to control the virtual thermostat using Google Home, or am I going to need to consider using Home Assistant for this functionality?

[BenLeo]

I'm also interested in this. Very interested in buying a shelly wall display, with a virtual thermostat, and integrate that into home assistant, so very similar question; are virtually thermostat available for Google home / home assistant?

[rjwill10]

I've been trying to figure out the best way to do this for a few days. If you have a Shelly H&T and a relay connected to your boiler, you can, in theory, set up a thermostat. However, the issue is that the thermostat function provided by Shelly is quite basic and lacks the advanced features found in systems like Nest or Hive unless you create custom automations.

The (dumb) thermostat I used to have allowed me to do various things: I could turn the heating off completely, set it to auto mode with minimum and maximum temperatures, and also set up schedules. These were all separate functions that didn't rely on one another.

I wanted to replicate these states with Shelly, which, in theory, you can achieve using a thermostat action (as seen in https://www.youtube.com/watch?v=GQ7JXvPVpcY)

 

The issue I've encountered is that the Shelly thermostat (which also displays on the Shelly smart display) is quite limited. For it to be controlled by Google Home, the thermostat function needs to remain constantly on. If you turn the thermostat off via the Shelly app (using the on/off button), it disappears from Google Home. This means a simple on/off command for the thermostat isn't possible through Google Home, and if you want to turn it off, you have to do so via the Shelly app. Turning it back on then triggers an error about needing to re-initialise the temperature sensor. I haven't yet resolved this error, but I suspect it involves waking the Shelly H&T from sleep mode so it can initialise with the thermostat. The Shelly H&T is always asleep, which complicates changing settings or adding actions. Strangely, to wake the H&T, you need to physically open the unit and press a button inside – a weird design choice, as there’s no way to wake the Shelly H&T via the app or the cloud.

To turn the heating off using the Shelly thermostat, you have to lower the temperature below the actual room temperature, but this doesn't turn the heating off entirely (which is my preference). To turn it back on, you need to set a temperature higher than the current room temperature. This is possible through Google Home but feels clunky and doesn’t integrate seamlessly with the Shelly app. For instance, if I set the thermostat to 21°C in Google Home, up from 18°C, and then check the Shelly app, it still shows 18°C, but the boiler will be on.

You can set schedules in the thermostat, but this doesn’t turn the system on or off; it simply sets base temperatures for given time periods.

I wrongly assumed I could use the thermostat feature as a device with on/off functionality. I also attempted to set up a second thermostat to handle turning the boiler on in the morning, but the system didn’t support this setup, as you can only use one thermostat at a time.

I'm still in contact with Shelly support about this issue. It might be more practical to set this up as a scene.

I haven't explored Home Assistant yet, but I've just set up a home server and plan to experiment with it. It appears Home Assistant offers more advanced capabilities for setting up a thermostat or heating controller, which is a shame because Shelly could genuinely compete with Hive and Nest if they enhanced this functionality. Imagine a smart thermostat for around £40 that doesn’t require a hub.