I would only buy it if it has an API that I can access like NIBE does. It should have WiFI and also be able to run completely without internet connection. No functionality should be limited if internet is down except for functions that rely on external data such as live electricity prices etc.

Also, it should be modular so it is easy to repair. Nibe sucks from this aspect and I would love a different heat pump that has better parts prices and was repairable.

As a final must have: Silence. The NIBE is way too noisy and we have it placed next to a bedroom which causes a lot of frustration. When the compressor starts it travels through the walls. I'm currently building extra walls to isolate it and reduce the noise.