Planning central ventilation system - volume flow, positioning?

Hello everyone,

I am currently planning the controlled residential ventilation for my new build (solid house). Here are the key data:
- Area: 251 m2, room height basement: 2.55 m, room height ground floor, attic: 2.60 m
- Volume flows (according to Helios planning tool) attached
- Central controlled residential ventilation with heat recovery planned in the basement
- Outdoor air through exterior wall, exhaust air through roof
- Planned controlled residential ventilation: Zehnder ventilation unit comfoair Q450 TR enthalpy or Helios EC500 W
- Floor plans with planning of valves and pipes attached
- 75 mm pipes in precast ceiling
- Flow velocity designed to < 2.0 m/s
- Overflow openings in door frames
- Implementation preferably as own work

Specifically, I have the following questions:
1. Do the volume flows and the positioning of the supply and exhaust air valves fit?
2. A granny flat is planned in the basement. Can the volume flows for this also be planned so that supply and exhaust air are equal and the overflow opening in the door to the corridor can be omitted? The main apartment and the granny flat would then form two independent ventilation areas.
3. A Finnish sauna (used 2-3 times/month) is planned in the attic. Would you integrate this room into the controlled residential ventilation or lead the exhaust air out through the bathroom?
4. Should the technical room where the controlled residential ventilation is located also get its own outlet for supply or exhaust air?
5. Should the ratio of supply air to exhaust air per floor be roughly equal? Currently, the ground floor and attic have significantly more supply air and the basement significantly more exhaust air.
6. The exhaust pipe for the storage room in the basement is very short. Could this cause noise?

Best regards
0per8or

We also have a Helios controlled residential ventilation system. Just for comparison: 1) We have about the same number of ducts on 165m² as you planned for 251, and that is actually too few for 2 rooms (in hindsight) 3) We also have a sauna in the bathroom and it is not connected separately - the bathroom connection is sufficient 4) Yes, we do 5) Yes, that is how it is planned for us, therefore e.g. also exhaust air in the hallways, which is missing in your plan 6) Yes, possible Which controlled residential ventilation device do you want to use?

5. Should the ratio of supply air to exhaust air per floor be roughly equal? Currently, the ground floor and attic have significantly more supply air, and the basement significantly more exhaust air

We have more supply air on the upper floor, i.e. air also flows down through the stairwell into the ground floor. This was planned that way and results from the rooms we have. Dust settles on the stairs instead of somewhere else. I see no advantages or disadvantages in this.

Which controlled residential ventilation unit do you want to use?

So far, a Zehnder ComfoAir Q450 TR enthalpy or a Helios EC500 W is planned. The exact decision has not been made yet.

4) Yes, we do

How did you implement the supply/exhaust air opening in the technical room? Pipe into the ceiling, laid once in a circle with a ceiling outlet attached? Or are there valves that can be connected directly to the distributor, or to a short pipe hanging below the ceiling?

Would take a ET for the EC500 W then as well.

Normal like in the other rooms too. Just saw, our utility room is also significantly larger than yours, combined with laundry room...

Use the planning service from Zehnder as a basis. If you then install their material and have Zehnder carry out the commissioning, the warranty is extended to 5 years.