Controlled residential ventilation: positioning of supply and exhaust air in my designs

And then there are three air inlets over the floor on the upper floor. I find that aesthetically poor and I wonder if it's not suboptimal because of cleaning.

But can you simply convert the floor valves on the upper floor into ceiling valves without further ado, or would that be enormous additional costs?

The position of the valves is fine. What concerns do you have about the floor valves? It couldn’t be better. This opens up completely different possibilities (in terms of piping) and is basically the more expensive variant of the installation. The floor valves can also become an optical highlight. Usually, only companies that know what they’re doing and understand their craft offer this and don’t just build everything according to a fixed pattern.

Regarding cleaning, you are worrying unnecessarily. As Pinky writes, it is super easy and the valves still look freshly installed even after years.

Since no cabinets or such are placed in front of the windows, you are not restricted in furnishing. Anything that provides an air gap can be placed on them. Desk etc.

We have a core drilling through the ceiling and the flat ducts come under the screed. The ceiling valves don't get any prettier because of it, but there is no need for a suspended ceiling.

This referred to the upper floor, as fewer people there have a concrete ceiling to the attic.

What did the structural engineer say?

He won't be asked just to be safe. It costs the general contractor extra if he has to recalculate and possibly redesign.

Since no wardrobes etc. are placed in front of the windows, you are not restricted in furnishing. Anything that provides an air gap can be placed there. Desk etc.

At least on the ground floor, it could happen that we do put sofas in front of the floor-to-ceiling windows. Sacrilege, I know. But we'll see.

Sofas are no problem. They usually have legs.

He is not asked just to be safe. It costs the general contractor extra if he has to calculate again and possibly rearrange.

With me, it was a call between the shell builder and the structural engineer, the structural engineer then gave the OK......

Isn't the exhaust missing upstairs, or did I overlook something?

They are marked as wall vents in both bathrooms next to the toilet. I also initially missed that.

My concerns about floor vents were in case something gets spilled. But that is probably rather unlikely. If vacuuming is enough for cleaning, then great. I didn’t know I was allowed to put something on the floor vents. In the bedroom, for example, I could imagine a chair where you can temporarily put clothes.

So would you leave all the positions as they are?
In the living room, however, I would move it. Otherwise, there would be a draft if you sit on the sofa underneath, right?

Dropping the ceiling upstairs is out of the question for me. Can you also put floor outlets in the dining room and living room? Then you can place a sofa with legs. I need a sofa with legs anyway for my robot vacuum cleaner.
And in the kitchen, then a wall outlet, for example? Or do you have to do everything uniformly on one floor?