OH3 + Homematic IP Thermostat + Google Assistant


I try to set up an Homematic IP Thermostat (HmIP-eTRV-2) with OpenHab3 and Google Assistant.
In the Google Assistant binding documentation (Google Assistant | openHAB) it is written, that you need to create an Item Group to properly expose it to GA.

However, I can also create an Equipment with the Associated Items from the Homematic Bridge and set GA Metadata there.


I still can’t seem to get it to run. Defining “Bad Eltern Heizkörper” as GA Thermostat and “Set Point Temperature” as GA thermostatTemperatureSetpoint doesn’t seem to do the trick. The Thermostat shows up without function in Google Home:

So my Question is: Do I need the group in this case or does the Semantic Model also create a group in terms of how GA “sees” it and I just need to work on my GA Metadata tags?

Any help appreciated!

Notice that the GA Group also has some GA Metadata (ga="Thermostat"). While you can use a Group that has semantic tags, that isn’t sufficient. The Group must have that GA metadata too.

Yep. So I did it with a “real” group now exactly as written in the documentation and it seems to work for normal heater thermostats. I created the groups via the webinterface instead of using the old method via text-files.

If someone else comes across this: You need to defined an Text item containing a string with a hint to what the thermostat controls. (GA hint: ga=“thermostatMode”) and then set it to a value.

I needed to use “heat” for my HomeMatic Thermostat and I set this value in a rule triggered by system start.

One Remaining issue I have is with a HomeMatic IP wall thermostat.

While it correctly controls all 3 associated thermostat when I select the temperature with the wheel, it does not, when I select the temperature via Google Assistant / Openhab. Not even Openhab alone leaving Google Assistant out of the equation.

So I guess I need to solve this remaining issue within the CCU3.