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

The manufacturer of our system has defined exact minimum distances here to prevent feedback.

Unfortunately, I can't find any information about this from Vallox anywhere. Not even in the operating and installation manual of the currently planned system Vallox ValloPlus 270 MV.

The only thing that comes to mind now: What about the noise level from the exhaust air on the terrace at a height of about 3 meters? Can you hear anything at all there? Or would it already have to be very quiet outside for that? (Info on this: The installation of silencers is definitely planned)

So for us, the following alternative to the combination cover (red/yellow on the west side) should be possible without much additional effort.

Looks reasonable. I would definitely prefer this option over the combination cover. And regarding the noise, I wouldn’t worry at all with the usual pipe diameters of these connections. Probably, you can only hear anything at all during total calm and at night. Have you already received any statement about the nominal air exchange rate?

The only thing that comes to my mind now: How would the noise pollution from the exhaust air on the terrace at a height of about 3 meters be? Can you hear anything at all there?

Our exhaust air goes from the technical room in the basement through a light well to the outside. And you can hear that very clearly within a radius of several meters from the air outlet. Although: you don’t hear the airflow itself, but the device that operates immediately behind it. The pipe length between the controlled residential ventilation and the air outlet is less than 1 meter.

Our exhaust air goes from the technical room in the basement through a light well to the outside.

That could also be done at our place since we also have a light well on the west side, but it doesn’t sound sensible to me. Because, as you yourself confirm, this opens the way for noise from the technical room to the outside.

Have you already received a statement about the nominal air change rate?

I have received values for the volume flow rates and know the room sizes. So I did some calculations:

Basic formula: air change rate = volume flow in m³/h / volume of the room in m³ (with 2.5 m room height)

Floor	Room	Size in m²	Type	Volume flow (planned)	Air change rate	Conclusion
basement	Entrance/hallway	14	Supply air	20	0.571428571	Barely okay, but is it sensible at all? Better capacity in the office!
basement	Office	21	Supply air	20	0.380952381	Too low
basement	Technical room/laundry room	16.36	Exhaust air	20
basement	Storage room	8.12	Exhaust air	20
ground floor	Kitchen	16.17	Exhaust air	40
ground floor	Living/dining	35.4	Supply air	40	0.451977401	Too low
ground floor	Pantry	5.14	Exhaust air	20
ground floor	WC	3.44	Exhaust air	20
attic	Child 1	11.57	Supply air	20	0.691443388	Rather too low
attic	Child 2	12.11	Supply air	20	0.660611065	Rather too low
attic	Bedroom	19	Supply air	40	0.842105263	OK
attic	Bathroom	10.38	Exhaust air	40
		172.69		320

In addition, I entered the building values into the Vallox planning tool and got different values (30/60 instead of 20/40). To me that smells like a slight undersizing overall, right? The tool from Helios spits out similar values. I suspect the planner just entered this into the tool and somehow ended up with the lower values. However, I expect a bit more here because the planning of a controlled residential ventilation system and its sizing is an individual matter and should not be done based on average values. As a first reference point maybe OK, but a specialist planner should IMHO look beyond that and be able to advise.

How do you see my assessments? Major blunders in the formula?

I am curious about the second round with him.

And one more question. In the large rooms, where 40m³/h volume flow is currently planned, two pipes are to go to one valve. From a noise development perspective, does it make sense to give each pipe its own valve?

That could also be done here since we also have a light well on the west side, but it doesn't seem sensible to me. Because, as you yourself confirm, this opens the way for sound from the technical room to the outside.

That is correct, but completely unproblematic for us since everything happens on the rarely used north side of the garden. And as said, you can hear the controlled residential ventilation at the air outlet, but compared to the noise caused by some air-to-water heat pumps installed outside, it is negligible.