Central or decentralized ventilation system - Who has experience?

It is probably more like 5000-10000€. And the 10k was already a more expensive GU price.

Bookstar is not entirely wrong.

We had four offers, each from different GCs. The "cheapest" offer was 15,000. All others were around 20,000.

Then the place must be different. We had 2 offers from GCs here, Vaillant Recovair central replaced Lunos e2 for about €10,000, for a 160sqm house. Acquaintances who build without a GC had additional costs of €5,500 compared to the decentralized offer.

I of course cannot tell you the surcharge from decentralized to centralized, as we planned with centralized from the beginning. The fact is only that none of the general contractors we asked offered a central ventilation system for less than €15,000 surcharge, so it does not seem to be a rarity here in Bavaria at least.

Ok, the standard houses of the GUs, which we had in the selection, had decentralized systems included in the base price.

Yes, of course the total price in BW, but it won't differ much compared to Bavaria. Back then we still paid something around 10,000, but that was a few years ago and I know from colleagues who are currently building that nowadays 15,000+ is more common. Quite a lot of money for something that "used to" not be needed. You never make it back through heating costs, but the energy saving ordinance forces you to. Comfort gain in new houses is very high, back then the drafty windows used to do that and they were free.