ᐅ Central mechanical ventilation with heat recovery: supply and exhaust air, door undercut

Hello.

We are currently planning the supply and exhaust air outlets for the (concrete) ceilings.
So far, the layout is as follows:

Basement: Exhaust air in all rooms except the storage cellar (currently no supply or exhaust air)
Ground floor: Dining/living/kitchen area (one open space) with both supply and exhaust air, office with supply air, bathroom with exhaust air
Top floor: Bedrooms and children's rooms with supply air, bathroom with exhaust air

A door gap of 5-8mm (0.2–0.3 inches) has been recommended for the room doors to avoid issues with air transfer.

Questions:
Are your ventilation concepts similar? Any experiences?
Does supply air work effectively only through air transfer under the door (in the basement, air would have to pass through the stairwell)?
What are your thoughts on the door gap (5mm (0.2 inches) seems common to me)?

Thanks in advance.

Are you really planning the location of all supply and exhaust air outlets yourselves? For us, this is designed by an engineering firm.

Hello @sven.conzi,

no, the ventilation system is planned by a plumbing and heating specialist.

I would try to keep the supply and exhaust air balanced on each floor. From a non-expert perspective, I imagine this helps to reduce air flowing through between floors. Even in typical supply air rooms like bedrooms, stale air can develop, and I wouldn’t want it to flow down stairwells into the basement to be extracted there. In any case, that would only be an option if the basement is within the heated building envelope (which I assume it is).

Hello @Alex85,

thank you for your reply. That wouldn’t be quite balanced for us. Yes, the basement is within the heated building envelope.

How is it for others? Where do you have supply air and where exhaust air in your homes?

bluminger schrieb:
How is it arranged for others? Where do you have supply air and where exhaust air?

In our case, the heating contractor planned it like this (no basement):
Ground floor supply air: 2× living room, 1× dining room
Ground floor exhaust air: 2× kitchen, 1× guest toilet, 1× utility room/freezer

First floor supply air: 1× child 1, 1× child 2, 1× office, 2× bedrooms
First floor exhaust air: 1× dressing room, 2× bathrooms

2× means 2 ducts per ceiling opening
1× means 1 duct per ceiling opening