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

Germ measurement after 2 years: Above average germs. Even if okay, cleaning is recommended at the latest after 5 years. Those are the facts.

I would not overestimate the filter. The coarse filter helps against insects and larger dirt, the pollen filter against pollen. I am pretty sure that germs can pass unhindered and absolutely sure that fine dust passes unhindered. For PM10 or even PM2.5, completely different filters are needed.

Yes, the terrible "germs" - as I said, just bury yourself and better stop breathing. What nonsense...

Let your experts define what germs are

And stop with your "facts" - with your "that's final" you underline no competence. These are not facts...

There is a difference between inhaling low concentrations of germs in the general outside air and them concentrating over time in [Kontrollierte-Wohnraumlüftung]. You are resistant to any kind of facts, aren't you? Most systems run for 5 - 10 years and longer because most people simply don't care. It's not like you can see the contamination. The fact is, in a system from 2011 or 2012, a germ measurement was taken after 2 years. No builder does that, but the company can afford it. The result was: contaminated. Enumeration of facts completed.

Yes, then all of us KWLers live with germs - good that you are so farsighted.

Apparently watched too much Pippi Longstocking...

Hello Lexmaul 79, as far as I know you are also planning a controlled residential ventilation system with heat recovery in your house, may I ask which company you are going with, feel free to PM if it is not allowed here. Thank you.

I installed it myself and the planning and delivery of the parts was handled by Lüftung.net (no link, that's the name of the company) - I have been very satisfied so far. The price-performance ratio for self-installation is unbeatable compared to offers from companies.

I had tried selfio before, but I was especially not satisfied with their calculation of the air ducts and the type/number of outlets. There, I was presented with a much better ventilation concept and everything was explained accordingly - why, how, what!