Ok, I am also researching right now. Central has more advantages. Is a central supply and exhaust system sufficient, or should it ideally also have heat recovery?
Something like this should actually be evident from your energy concept, whether heat recovery is needed or not. But why wouldn't you plan for one? That would eliminate one of the major advantages (ventilation with minimal heat loss).
I have not seen an energy concept. We have a decentralized exhaust system included in the price. Others are possible at an additional cost. I am not really familiar with the topic yet. But I think decentralized is probably not sufficient.
Do you only build according to the [Energieeinsparverordnung] or do you achieve [KfW55] or something like that? That has to be calculated somehow and accordingly, it has to be listed somewhere which measures are necessary for that, meaning which insulation, which window values, which heating system, etc.