Ceiling suddenly too small for controlled residential ventilation!

Do you mean the proposed controlled residential ventilation with unknown system technology?

Yes. GCs have a very hard time with plant engineering from manufacturers that they do not have in their standard.

Ok, so I would have to ask the (assigned a few days ago) installer. He definitely seems to be an elco installer!

GU and unknown/new plant technology is dangerous.

It doesn't necessarily have to be unknown. Some manufacturers have different designs. If there is something hanging, that's good.

Ok, so I would have to ask the (assigned a few days ago) installer.
He definitely seems to be an elco installer!

The name was not known to me before, but on the website there is also a hanging device shown in a picture. If you can position it a bit higher, you could put a washing machine and dryer underneath.

Regarding heating, the contract states:
*according to the construction service description including towel radiators. A circulation line is already included as standard. A air/water heat pump from the company Duplex, ELCO or Viessmann will be installed.
*Credit amount (-3927.45€) for the omission of the air/water heat pump and installation of a gas condensing boiler including solar system with 2 flat collectors from e.g. the company Buderus.
Execution including underfloor heating.

And regarding ventilation:
*not included in the scope of services and can be commissioned additionally upon request.
*Execution of a central ventilation system with heat recovery on the ground and attic floors. Ventilation outlets for supply and exhaust air will be installed in the respective ceiling above the floor to be ventilated.
A central ventilation unit with heat recovery from the company Pluggit, Maico, Dimplex, or the aforementioned, will be used!

Where is the floor plan so that one can assess whether the [Kontrollierte-Wohnraumlüftung] does not fit? It’s not just the size of the system that matters, but you also need a continuous wall on which you can run the pipe up, whether from the [KG] to the [OG] or from the [EG] to the [OG].

Has the [Kontrollierte-Wohnraumlüftung] been commissioned with the ventilation planning/location planning, etc.? Sounds to me rather like it has not.

If it had been commissioned, the ceiling elements would already have to be provided with cutouts for the ventilation plate. Those are actually already planned and ordered if things are supposed to start now.

Sounds like both sides slept through it!