Atypically high offer for ventilation system

Our screed is also 18cm.
Excerpt from the BB:

A cement screed is installed according to the manufacturer's guidelines. The screed is suitable for underfloor heating. The total floor construction including the wearing surface is 18 cm on the ground floor. Insulation boards, thickness according to the thermal protection certificate, are fully laid beneath the underfloor heating system. The drying ventilation after screed installation is carried out by the client according to the contractor’s instructions.

Well, his statement is that a controlled residential ventilation system is simply a money-making scheme. He would install it, but he is not a fan.

Well, his statement is that a controlled residential ventilation system is simply a money-making scheme. He would install it, he's just not a fan.

Our building supervisor said exactly the same thing about the first house, and the energy consultant(!) agreed with him. We then decided against it, later got extremely annoyed, and had decentralized units retrofitted in some rooms in a cumbersome way. That was better than nothing, but by no means did it come close to a central controlled residential ventilation system.
For the second house, a central controlled residential ventilation system was out of the question for us. If that's no longer financially feasible, then at least have a decentralized one installed.

And isn't there an option without floor installation, e.g., over the wall?

They have to be distributed in all rooms; that only works via floor or ceiling.
In our case, they are in the ceiling, which was lowered. But that was planned from the beginning.

Well, his statement is that a controlled residential ventilation system is simply a money-making scheme. He would install it, he's just not a fan

I agree with that. I have been living in a KfW55 house for 16 months and decided against both a decentralized and a centralized ventilation system and have not regretted this decision so far. Ventilate for a few minutes once a day and that's it. Even when we are on vacation for 3 weeks and no ventilation takes place, the humidity levels on the measuring devices I have placed in all rooms remain fine.

Air out once a day for a few minutes and that's it.

We'll see each other again in 5 years in the thread "Help, mold everywhere in the house and guests say they get headaches from being here."
Ventilating once a day contradicts all recognized rules for ventilation concepts in new buildings.

By the way, this is what the CO2 concentration looks like DESPITE controlled residential ventilation in a 60 sqm open space when 4 people cook and spend the evening together:

I agree with controlled residential ventilation. I know both the decentralized variant from my last house and now during the renovation the decentralized one. And I stick to it: never again without.

Yes, you can also ventilate manually. But then you have to do it throughout the entire house a) several times a day b) in all weather conditions c) it does nothing against the mustiness in the bedroom at night d)...

But yes, without money it gets difficult. However, the second choice, decentralized controlled residential ventilation, is still the perfect alternative (e.g. in the window reveals). And if that is still not possible, please use window rebate ventilators.

Anyone who says how great it is in a new building without controlled residential ventilation does not know a functioning controlled residential ventilation. Mold prevention also works without problems, but permanently fresh air (and ideally thanks to a suitable filter also without pollen) does not work or cannot work as with controlled residential ventilation.

P.S. The price of T€ 14 without floor heating increase (although I do not understand why the increase is necessarily required. Either there is a filigree ceiling - there the pipes are installed alongside other things - or a shuttered ceiling - there the pipes can also simply be laid. Depending on the statics, a bit more steel and/or concrete may be necessary. The floor structure does not change at all. You can already tell from this that the general contractor simply does not want to deal with it.) is a bit too high.

I have to correct myself. By the 3k knapp he also only means the ceiling, not the BP.

Floor slabs
Reinforced concrete ceilings made of prefabricated filigree elements finished on the underside, with topping concrete, thickness and reinforcement according to structural calculations. The ceiling above the upper floor is executed as a wooden collar beam ceiling. The ceiling joints are closed with fiber-reinforced joint filler.