How is it with the central ventilation system? It is often said that it is difficult to clean, which is understandable since you cannot get into the ducts. Contamination is also said to be a problem.
We will speak with the construction company tomorrow to see if a central system might still be possible.
Today's systems can usually be cleaned without any problems. Contamination is only an issue if filters are not replaced or the system is off for an extended period. With proper use, it is not a problem at all.
We have the [Zentrale] from Pluggit. Are very satisfied with it. But that won't help you much. But on the topic of yes or no: definitely YES! Our neighbors don't have any ... you can tell by the air. And our heating installer once casually mentioned that with today's construction methods, you would actually need to ventilate every 2 hours to prevent mold and the like.