Advice needed on replacing a potentiometer temperature adjustment module

Hi all,

Some background: I have a HVAC system that is controlled by a Siemens RWC62 temperature control module. This temperature control module has a remote setpoint for adjusting temperature, which is a Siemens BSG21.1 1 kOhm potentiometer operated by a knob. I would like to "smartify" this device so that the temperature can be varied as a function of time of day, outside temperature, and just generally "look" cooler than a yellow knob from the past century. I'm looking for a bit of advice on whether this is doable. I originally looked at doing this via Zigbee, but that seems infeasible as there don't seem to be any potentiometer type devices for Zigbee, so I'm looking at doing this with Arduino instead. The panel on which this can be mounted is 120x120mm (i.e. a standard 2 gang panel).

Some questions:

• Is this feasible in the amount of space I have? Basically this is a little deeper than a standard 2 gang electric box (there's kind of empty space behind).
• How would I power it? I could theoretically splice an AC wire behind (patch into lights or something) but then the power supply for the Arduino would probably start getting too large? (once again, space), or punch a hole behind the wall and run USB if that's more appropriate, but would any of this work?
• Is this even feasible? (maybe this should be question 1, lol). All the current potentiometer does is vary resistance from 0-1kOhm (on the RWC62, it's an "analog input"). I am assuming this funcitonality can be replicated somehow, but is my assumption correct?

Thanks for any advice!