Decentralized ventilation system that is hardly visible on the exterior facade

What do you mean? What does that have to do with physics?

Plenty, and not cheaper by the dozen. Particle sizes, flows, cross sections, lengths, stagnation pressures, spring stiffnesses, and much more (even just in theory). How do you attach the brushes to the endoscope probe with the coaxial suction hose? - I love this smarty-pants logic: what one cannot imagine in its complexity must therefore simply be true, after all, "everything easyeasy" is printed in bold in the brochure. Where did you place maintenance flaps, how do you seal the system for cleaning???

Plenty, and not cheaper by the dozen. Particle sizes, flows, cross sections, lengths, stagnation pressures, spring stiffnesses, and much more (even just in theory). How do you attach the brushes to the endoscope probe with the coaxial suction hose? - I really love this know-it-all logic: what you cannot imagine in its complexity must simply be true, after all "everything easyeasy" is printed in bold in the brochure. Where did you place maintenance flaps, how do you seal the system for cleaning???

Your nonsense is unnecessary. Each strand can be cleaned separately, just insert a cleaning ball and create a vacuum on the other side with a vacuum cleaner. It’s not rocket science and works perfectly.

Your rambling is unnecessary.

I couldn’t have said it better:

Each strand can be cleaned individually, simply insert a cleaning ball and create a vacuum on the other side with a vacuum cleaner. It’s not rocket science and works wonderfully.

Ignoring the rambling, your answer to my question about the maintenance flap is: "the mouth of each strand into the central unit performs this function," and to the follow-up question about the instruments: "as an instrument I use a cleaning ball, I forgo endoscopic control of the cleaning success in full trust in the ball’s respect for my expectations." Good, so your vacuum pump is a household vacuum cleaner (whose power is as flexible as the variation in the lengths of the individual strands). That we theorists always have to consider the Earth a sphere – when every practitioner knows it’s a disc. Tssk.

If you call the topic of [Hygiene] a myth, you are simply wrong. [Hygiene] is wonderfully manageable, you just have to do something about it. Clean, change filters... Many do not do that and the manufacturers downplay the issue. For me, that’s not something I want to deal with, I don’t want to have to think about such things.

If you call the topic of hygiene a myth, you are simply wrong. Hygiene is wonderfully manageable, you just have to do something about it. Clean, change filters... Many don’t do that and the manufacturers downplay the issue. For me, it’s not something I want to have to think about.

I call it a myth with regular filter changes, not the topic of hygiene itself.

And to specify the cleaning more precisely: there are inspection flaps for every duct and every floor. Otherwise, the vacuum cleaner certainly wouldn’t manage.

I opened our exhaust valves after 2 years of use and both the pipes that intake and those that exhaust: completely clean .... where should dirt come from when you have filters in front that you change regularly?