Have you thought about DECT driven thermostats like the 301 from FRITZ?
You can also combine them either with an offset temperature or use an external temperature sensor so that it doesn’t measure the temperature directly at the radiator.
I’ve combined this with OH the following way:
There are two heating plans
- one if somebody is at home
- one if nobody’s at home
- and of course you can change the setpoint temperature via openHAB
What I like about thos is the e-Ink display and power consumption is OK.
And they are very responsive when you manually operate them
I previously used the Zwave thermostat from Danfoss and except the design I was disappointed.
The buttons for operating it manually are wobbling and you don’t get a good haptic feedback when pressing them. Also I takes quite a while until the display turns on.
And for some reason the valve completely opened when the battery was empty which i realized in the evening since the temperature in the attic was around 25°C.