No normal wall construction breathes if it is executed according to today's standards. And that means airtight. The myth of the brick that breathes is due to a faulty experimental setup and has been disproven. (Like iron and spinach..) Even the brick industry no longer advertises it.
You can ONLY get water vapor ("humidity") out of the house by ventilating, since the building envelope is usually airtight. If your builder says otherwise, I would get an independent architect/expert or someone like that to supervise the construction. The builder is selling you apples for pears.
I personally have been living for 1 year in a newly built semi-detached house as a tenant. With decentralized ventilation. Brand available on request via PM. I am very dissatisfied!
a) Noise level due to the many openings in the exterior wall. The street can be heard as if a window were open. Really.
b) Noise level due to the fans: not monotonous because of the "switching," so you don't overlook it. At 25% (lowest level) barely bearable, at 100% it roars like an old extractor hood.
c) Air exchange rate insufficient: In our bedroom there is no "fresh air" in the morning, and in the bathroom I always have to ventilate manually after showering to get a somewhat tolerable climate.
d) Filters have to be cleaned constantly and the ceramic elements often have to be vacuumed. Very elaborate process! Filter replacement with central ventilation is much faster (according to colleagues 30 min once a year).
e) Due to the cross-ventilation principle, fresh air is blown into the bathroom 50% of the time and exhausted through the bedroom... Now everyone can imagine what can waft over there. Not nice.
Oh yes:
We have one in every bedroom and bathroom, 2 in the living/dining/kitchen area, and 2 in the attic. 155 m² according to the living space ordinance.
