Controlled residential ventilation system - decision support

We have the Zehnder 350 for the EG and OG with a similar square meter area and only hear the ventilation at the highest setting. Normal operation is the medium setting, and I actually don't hear any noise there, even if it is quiet.

Do the systems differ in the valves and piping used? What cross-sections are planned? What types of valves and what orifices are there? How is the fresh air supplied from outside? Are there any differences?

How is the basement integrated into the ventilation concept? Is there a ventilation concept for the basement? Is there air generated there that should be vented?

I would definitely include the basement in the ventilation concept. We have done that as well. We are using a Vallox MV-350E.

We have the CWL-300 installed in the basement, with a similar square meter area, but in our case all basement rooms are ventilated. We also only hear the ventilation (i.e., the air noises) at level 4 (of 4), and at level 3 when it is very quiet. The standard setting for us is level 2. The device itself is practically not audible at the top of the basement stairs even at the highest level (of course, the door to the technical room must be closed...).

OK, thanks already for the answers so far. We will ask how much it costs to additionally integrate the basement into the ventilation system. It shouldn’t actually cause much more additional costs (I hope), since the piping would be significantly shorter than in the two residential floors.

Now I just thought of something else: Our living room is about 30 sqm and so far only one air inlet is planned here. To achieve the necessary m3 capacity for air circulation, in my opinion, a higher pressure would be required with only one inlet than with two inlets. Disadvantages could then be: stronger "draft effect" and higher noise levels.

What do the experts think, would it therefore not be better to plan 2 air inlets for a 30 sqm room?

We have planned about 20m³ of air volume for every 20sqm of living space. For example, in a 35sqm room, 2 plate valves 100mm each with 20m³ of air.