Controlled residential ventilation - Planning the positions for supply air / exhaust air

The person responsible at the GU has now put me in contact with the manufacturer and provided the detailed planning documents so far. I can now clarify all the detailed questions directly with Vallox. The good thing is, the conversation today was honest and transparent. He said he himself does not have the necessary detailed expertise to answer my questions. That I have to get stuck into it myself was somehow clear to me. Because even before signing the contract, it was obvious that the GU rarely installs such systems.

The question is only how I convince the contact person on the manufacturer’s side that I would like to separate supply and exhaust air. They seem convinced that their combined grille works and meets all standards. We’ll see .. I will keep reporting.

How high should the air exchange rate be in practice? There is this infamous minimum value of 0.5 1/h for living spaces from the standards. For an office with two people, that will not be enough, nor for a living/dining area.

What values have you designed your system with or have you used in practice (for a good result)?

They seem convinced that their combination grid works and meets all standards.

And they are also right about that. It works(c).

The question would rather be how much it costs if the pipes are laid separately. I really can't imagine a huge price difference there.

1 against 1! :p Are there any other opinions on the topic? ;) I am still interested in practical values from other builders.

Seriously: For a layperson, it's really difficult to decide what the best option is and what will bring the most joy in the end. You can probably also overthink it.

In the meantime, I have spoken with a technician from Vallox.

Generally, he recommends, if possible, to take the outside air from the north side of the house (due to the temperatures in summer). However, since our terrace is located there, we should rather take the west side, as smells from the grill or possibly smokers present could otherwise more easily enter the house. He also confirmed to me, as expected, that the combination cover works.

Regarding the dimensioning of the system and the individual volume flows, there have indeed been significant changes compared to the initial calculation. If the system were dimensioned according to the DIN standard, the 270 MV would suffice. Even though it would then already run at 60% in normal operation. Taking into account all requirements (clothes drying, number of people in the study, etc.), we come to the next larger variant, the 350 MV.

In addition, the supply air from the entrance area (overflow area) was removed and the capacity in the office increased accordingly (dimensioned for 2 people). We then designed the system together using individual values instead of using blanket values per valve. There will now be 2 valves in the living room, each supplied by one pipe, to achieve a better distribution and not "strain" the valve too much.

For all those who are still in the exploration phase, here are my humble recommendations:

[*]Decide for or against a central controlled residential ventilation system before the first floor plan draft – this allows you to intelligently and unobtrusively consider space for the pipes directly in the floor plan if necessary.
[*]Inform yourself about the basic technical aspects of such a controlled residential ventilation system beforehand, so you can critically question plans and not simply approve something blindly.
[*]Dimension the system a bit larger than required by DIN so that it can run more quietly. Of course, it should not be too large from an economic point of view, as that would lead to potentially unnecessarily higher electricity consumption.
[*]Insist on an individual plan based on the planned room usage concept.