Decentralized controlled residential ventilation so expensive?

For cost reasons, a decentralized system was explicitly requested. There was also about €6,000 discussed äch. That it would cost almost twice as much, I would never have thought in my wildest dreams.

I have already contacted a nice ventilation installer. Although his focus is on industry, he offered me his support. He said that I still have enough time and should not rush. Tomorrow I am going to him with the plans.

Regards Robert

Approximately €6000 sounds very good for a central controlled residential ventilation system for 130sqm. In a solid house, there should also be no problems if this is installed "retrofitted" - as long as the screed has not yet been laid. And drilling through the floor slab/ceiling should also not be a problem.
Best regards

The builder does say that moisture diffuses through the walls to the outside, but somehow that still doesn't reassure me. I have read so much about it in the past few weeks that I have become even more uncertain. Everyone writes and says something different. How is one supposed to form an opinion like this?

Hello Robert, sorry, your builder's statement just makes me shake my head. Moisture from the living rooms diffusing completely through the exterior wall... - No words - Have a look on the internet at how many homeowners have had massive mold problems due to thick insulation without a ventilation system. Especially in the first few months after moving in, a ventilation system is nowadays almost indispensable if no one is permanently in the house to ventilate. Apart from the additional comfort of not having to ventilate anymore... At the beginning of our own information process about building a house, we were also rather skeptical about the ventilation system, but after many talks with homeowners who are already living in the house, we are convinced that a controlled residential ventilation system with heat recovery is one of the most sensible investments when building a house.

That depends on the wall structure and how KfW70 is achieved.

If it is a standard 36.5 T10 with interior and exterior plaster and the house is calculated for KfW70 through an air-water heat pump and a controlled residential ventilation system with heat recovery, that does not change the wall structure and has nothing to do with "over-insulation." Almost all houses built in recent years without controlled residential ventilation would have to be discarded. That is just as nonsense. But that's another topic.

KfW70 is achieved as follows:
- Basement walls and floor slab with 14cm perimeter insulation
- Exterior walls made of sand-lime brick with ETICS WLG 032
- Mineral insulation between and under the rafters (total thickness 22cm, WLG 032)
- 2 solar collectors to support hot water preparation
- Air heat pump and underfloor heating in the ground floor, first floor, and attic
- Large-area radiators in the basement
- Triple-glazed insulating glass

Regards

And now you've got plastic around it.