The ventilation system is loud and disturbing

Where would these filters need to be replaced? There are definitely no filters on the valves. Are they in the system itself?

So for me, there are filters in all the valves. Of course, there are also central filters in the system itself. These also need to be replaced. Ours were due for replacement relatively quickly the first time because dust naturally gets caught in them during the construction phase. Please take some photos of the valves, including opened ones. In the valve insert, there is a clamping point where the filter is installed (must be installed?). The system would get completely dirty if the filter is missing at the extraction points.

I only know filters from the exhaust points, not from the air inlets. And of course the filters inside the system itself. You can take them out, look at them, vacuum them if necessary – you have to change them regularly anyway. Same goes for the exhausters.

Noise can come from turbulence in the air inlets or through the pipe from the system itself. A silencer is installed between the ventilation unit and the duct, you should be able to see it. For me, these are four 20x50x150cm boxes, which are hard to miss.

There are definitely no filters on the valves.

But there should be some on the intakes. That can also affect the noises, completely different flow behavior.