Controlled residential ventilation manufacturer selection - How to approach?

I can make good use of your contributions. Many thanks for the feedback and also the counterproposal regarding the valve placement. Regarding that, I estimate that the principle "maximum distance from valve to overflow space" applies. Isn't it unpleasant when I'm working at the desk and air flows out of the valve above me? This thought led me to place the valve (supply air) in the room so that people rarely stay underneath it.

I want and will have a plan made. In advance, I would like to acquire some knowledge with your help in order to be able to evaluate the planning later. Of course, I will also present the planning here.

Then ultimately only the question of the manufacturer remains. Zehnder is currently at the forefront. However, it is not the cheapest either, if one may say so in general.

I'm almost done with the manufacturer selection... a) Viessmann (because my installer promotes it) b) Helios (because the installer would also install this as an alternative) c) Zehnder (my favorite) I think the price will decide now.

Different topic: duct routing and distribution. (Should I start a new thread for this?) Supply air on the ground floor (DINING and LIVING ROOM) is routed on the basement ceiling/below the screed. -> Floor outlet. Supply air on the upper floor (KID1&2 and bedroom) is routed in the ground floor ceiling/on the filigree slab -> Floor outlet. //In the attic there is also a floor outlet planned (not visible in the plan excerpt)

Can I pass this on to my structural engineer like this? Is 47m³ on one valve (kitchen) okay? Or should it be split over two valves?

In the corridors, no exhaust air is needed as these are overflow areas. If you do plan some, then what is there is sufficient, and you don’t have to install another vent in the kitchen. Only the planned one must be a bit larger or adjusted to the appropriate air volume. But that is obvious anyway.

In the basement, supply air is missing since you also plan exhaust air there.

In the hallways, no exhaust air is needed as these are overflow areas. If you still plan some, then what is already planned is sufficient and you don’t need to install another vent in the kitchen. Only the planned one has to be somewhat larger, or also adjusted to the appropriate air volume. But that is clear anyway.

In the basement, there is no supply air since you are also planning exhaust air there.

Can someone show me pictures of the supply or exhaust air ducts in the floor? Looks kind of strange (I saw it recently on Instagram with a builder ) Are there different coverings or also different sizes depending on the manufacturer, similar to the air-water heat pump?

Could these also be covered with furniture, or do they have to remain "open" to ensure air circulation?

As long as there is an air gap, you can put anything you want there. Sofa, bed, etc., no problem at all. However, this may, of course, increase noise generation.

Are there different coverings or also different sizes, depending on the manufacturer,

Certainly, there are several approaches, as well as several manufacturers and options. Everyone has their own system, and in addition, of course, you can somehow combine everything with each other.

For example, I have a Wolf system with Helios piping and Torx valves.

As long as there is an air gap, you can put anything you want. Sofa, bed, etc. all no problem. However, this may of course increase the noise development. Surely there are several approaches here and also several manufacturers and several options. Everyone has their own system and in addition, of course, you can somehow combine everything together. For example, I have a Wolf system with Helios piping and Torx valves.

Are there also specific systems that have a VERY low noise level? Preferably models known for this on the market? My girlfriend is very sensitive to it – we should choose a system here that only has a low dB value.