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

Ozone cleaning sounds fancy... If there are damp spots in the piping system, the pathogens will probably be back after a few days.

You

I also mentioned this brush cleaning to the architect. He just gave a tired smile and told me that this is no longer how it's done nowadays. That used to be a cleaning system in the past. It doesn't kill germs either. Today, high doses of ozone are used for cleaning; during this time, a few hours, of course, you must not stay inside the house.

So your weird online shop told you something about never cleaning, and if so, then with such a brush? Are you sure you were advised and not just taken for a ride? My salesman and the architect present at the time at least honestly gave me maintenance intervals and also explained that my conventional, old methods won't work. You just have to realistically budget these costs of 700 euros every 5 years.

Apparently, you really believe everything you are told...
Why don’t you try ozone cleaning on your toilet or in your wife’s handbag (which can sometimes be even grosser inside than toilets). Then also under all the cabinets, behind the kitchen unit, etc.
Your salesman can surely recommend a good provider to you (who each year will be happy to have found another fool with germophobia).

I'm out of this topic, it’s getting too childish for me since Grym is too resistant – only open to salesmen. I would have liked to have you as a customer

No, my "weird online shop" didn't tell me "never clean" - that was not even an issue because I don't see that with them either. I came with requirements accordingly and they were implemented. You don't need to come now with platitudes like "taken for a ride"...

And as I said, your architect from the model park (I could laugh more than just that) is the expert on ventilation systems? That's normally not their business... but you seem to be dealing with an all-round pro there.

As I said, your 700 euros are already ridiculous if it’s only about ozone cleaning. I do that completely for free myself - if you commission it externally, it might cost about 100 euros.

Apart from that: You’re supposed to do that every 5 years? Why it should be a breeding ground for germs there, you still haven’t been able to name so far. And why only after 5 years? and not every few weeks/months? Germs multiply exponentially... but what am I telling you about numbers?

By the way, the "old brush method" possibly cleans breeding grounds of germs - if you were correspondingly open-minded, you would have included that in your reasoning. But ozone cleaning only helps if you remove the cause of the "germ infestation"...

If the aforementioned company builds every house with controlled residential ventilation, then the architect should already have some knowledge of the matter. No, he did not name a company to me. He also knew that we come from another city and therefore knows that we would not choose his local cleaning company because we want to live and build elsewhere. He, as well as the salesman, simply informed me honestly that controlled residential ventilation is not a maintenance-free technical system and that, similar to a gas boiler, it requires regular inspection and, similar to industrial air conditioning systems, it requires regular cleaning and disinfection.

Behind my furniture, there is significantly less air exchange than in ventilation ducts, ergo fewer germs entering. Don’t worry, the furniture is, of course, 10cm away from the wall. Nevertheless, not nearly as many germs come through there as through ventilation ducts, which circulate the entire air volume multiple times and are therefore exposed to far, far more germs per unit of time.

Now an air conditioning system is being equated with a [Kontrollierte-Wohnraumlüftung] - as I said, real professional statements . And why an architect at a show home park should still have expertise in [Kontrollierte-Wohnraumlüftungen], I don't understand - what is his role there? Why does he still oversee the houses years after moving in?

I think it’s good, Grym, that you are engaging with the subject matter and are brave enough to share your point of view here; that’s what a forum lives on. Unfortunately, I find the answers here today somewhat unsatisfactory and unobjective. I myself am more in favor of a controlled residential ventilation system with heat recovery. Nevertheless, one can always look beyond one’s own horizon. What would be the argumentative objections against Grym’s solution?

is right. I also know from other forum posts and know that he can sometimes be a bit difficult (not to say stubborn or resistant to learning). However, he has posed a legitimate question here, which is based on the statements of a seller and an architect. Both would probably prefer to sell something and rather dispel potential counterarguments. In this case, however, they do not – so a follow-up question is justified. But from almost the very beginning, a negative basic attitude was directed at ’s question (which certainly stems from past threads) – which I do not find appropriate in this case.

Since I do not have a controlled residential ventilation system (but rather a decentralized one), I can only respond to you in outline. A ventilation system with heat recovery will never pay off. That’s just the way it is. Someone who acquires such a system is more concerned with comfort (and the necessary ventilation). It has already been written in this thread – especially in the bedroom, a lot of moisture accumulates. We found this out when we had to clean our filters in February. Quite a bit passes through. Our general contractor also suggested exhaust air vents with window rebates – argument: nothing else pays off. Through the negative pressure created by the exhaust air vents in the wet rooms, the used air is pulled out of the other rooms and expelled. However, these exhaust air vents would have to run continuously for proper air exchange. Thus, for example, you would permanently suck in cold air during winter, which would then have to be reheated.

Regarding the statements about cleaning and germ formation, I can say little. However, since the argument “moisture leads to germ formation – where should moisture come from in the intake pipes?” is consistent, I also suspect potentially other construction defects. Or did the germ formation possibly originate in the exhaust air pipes (where the moist exhaust air passes through)? Would that be possible? To what extent could such germs then enter your household – since the airflow carries them to the outside?