Controller Recommendation for 2kW Electric Heater and Multi-Room Ventilation System

Hello. I would like to control a ventilation system in a flat with an electric heater. A 2kW heater with a supply fan in one duct and two exhaust fans in different rooms. The heater should switch on when the temperature drops below a certain level defined once and permanently, but must not operate when the fans are switched off. The operation of the fans, in turn, is controlled by the user via two potentiometers in different rooms - the potentiometer should switch on the speed in a given room and the supply (well, and the heater depending on the temperature). I am looking for some controller suitable for this task. The industrial ones I've turned to in the past seem to me to be form over substance. Thanks in advance for your help.

If you want to build it yourself and have the basic knowledge, I recommend a simple controller based on a microcontroller. The cost is small and you can adapt it to your own needs. https://www.google.pl/search?q=termostat+atme...AvQsAQIQg&biw=1920&bih=1027&dpr=1

I would prefer a ready-made controller for the software, but I have also thought of an Ardu solution for this. For control, two surface-mounted potentiometers wired up to analogue inputs, such a board for fans and a relay for switching the heater. Does this make sense?

If the board can withstand the current of the fans, then yes. Same with the relay. Remember to measure the temperature, you can implement this with a DS18B20.