Hello everyone,
thank you first for the discussion.
In another forum I found a study. It states that in a single-family house it is not necessarily required to work according to the exhaust air principle. Thus, air circulation in the area of the doors is quite allowed.
Therefore, I would find it very practical to place the supply air valves there on the 1st floor, as I do not see many other options. After all, the unit should not be above the desk or bed and the rooms are not that big. The only thing is that I would arrange the exhaust air in the bathroom above the toilet...
Any concerns from you? Unfortunately, I have a gun to my head and have to decide by 3:00 PM today.
Thanks and regards
Robert