Controlled residential ventilation yes - heat recovery no - justification in the text!

Just a counter-question, aren’t centrally controlled residential ventilation systems also installed in hospitals? Or what is used there?

Exactly - but it's not rocket science either.

I don't have a geothermal heat exchanger - for me, it's more of a breeding ground, it's expensive (just the intake towers) and the benefit is too low for me.

Air is drawn in at the north gable, exhausted at the south gable - cooling by air conditioning.

and why was the show house still contaminated? not visible, but measurable.

We cannot answer that for you. Maybe there was sloppiness during construction - that can even happen in a show house.
If you are that anxious, then just ventilate conventionally or decentrally.
I find window rebate ventilation or the like crap, first build airtight and then use windows for draft.

Which germs and in what concentration were found in the show house? Why only in the supply air? System with humidification (moisture = possible breeding ground for germs)? Where is the house located so that such harmful germs can even enter the house from outside?
You should confront the "facts" from the seller with these questions.

P.S. If the seller assures you that heating the house with lignite is the best option, is that for you also a "fact"?

The entire thread is based on a statement that was simply carved in stone, which is not (supposed to be) debatable – as are the costs. They are assumed, continuously calculated somewhere, and then they are fixed. Just like with every thread from Grym...

That is the fundamental problem and it makes a discussion from the OP itself unobjective.

What does not fit argumentatively with Grym's "solution"?

[*]Single-family houses have no wet rooms
[*]He wants to do exhaust air in bathrooms/kitchens – but a bedroom has hours-long moisture emissions from the occupants. Likewise the other living spaces – they are simply ignored.
[*]Uncontrolled exterior wall penetrations are simply listed – that the airtight envelope is thereby made absurd is just incidental...

Oh, I just noticed that our Grymi started the identical thread again in the green forum - unfortunately with the same results . Pretty trollish behavior...

But you wrote something interesting there: The controlled residential ventilation in the model house was cleaned with ozone? That’s supposed to be elaborate and cost 700 bucks? That’s when you realize how they fooled you

A cleaning is done with a special brush system, which you can by the way borrow and do yourself .

And if that’s not enough for you: I can also "clean" it with ozone - that’s not a problem. Doesn’t even cost me anything .

I also mentioned this brush cleaning to the architect. He just smiled tiredly at first and told me that people no longer do it that way nowadays. That used to be a cleaning system. It doesn’t kill germs either. Nowadays, high-dose ozone cleaning is used, during this time, a few hours, of course, you’re not allowed to stay in the house.

So your strange online shop told you something about never cleaning and if at all then with such a brush? Are you sure you were advised and not just taken for a ride? My salesperson and the architect who was also present at least honestly told me the maintenance intervals and also explained that nothing would come of my conventional, old methods. You just have to realistically factor in these costs of 700 euros every 5 years.