Alternative to central/decentralized ventilation

Heating and ventilation are indeed very closely related to how much energy is consumed in a building, and optimizing this is by no means unreasonable. However, it is not about short-term savings like window open -> heating off, but about the long-term processes and the control of these.

I had previously assumed that the important point here is especially "Wärmerückgewinnung" and that the two devices can/must communicate with each other to work more effectively!?