@mstormi
I see, so then B it is for me. Thanks for the advice! Then my next step is to figure out how I will wire it up, i.e., where to place my OH central unit and how to connect the actuators, temperature sensors and per-room input units (if I decide to have such).
The reason why I was thinking about Arduino is that I thought of having a unit consisting of
- Arduino
- suitable temperature sensor (as suggested by Confused)
- rotary encoder / buttons for setpoint input
- LCD for local setpoint / current temperature display
- 230V relay (or optocoupler / triac combo) switch for valve actuators
- ethernet shield
in every room which has radiators (there are 3 such rooms), since each of these rooms has ethernet plugs anyway, and so it seemed the easiest way how to connect to the OH central unit in a different room. Of course, for a simple setup and testing I can start with just a temperature sensor and valve actuator connected directly to OH in one room, and then decide how to extend from there.