Controlled residential ventilation - supply air and exhaust air executed differently

Hello everyone,

I just noticed that in our basement (Wohnkelle) 2 rooms are executed differently than shown in the execution plans.

We have a large room in the basement with large windows due to the slope, where exhaust air was installed contrary to the execution plans. The execution plans show supply air. The reason given was that we installed kitchen connections, but we only had them provisionally installed in case the room is ever used as a separate apartment. Currently, a guest room is planned.

In the other basement room, a storage room without windows, supply air is installed, although exhaust air is shown in the execution plans.

I assume that the controlled residential ventilation planner changed this on their own authority. But I did check and approve the execution plans explicitly.

In the large room, I could still live with exhaust air because of a potential kitchen at some point, but in the basement room, it makes no sense to me at all. All other basement rooms have also received exhaust air.

The site manager of course says it's not a problem, the ratio must fit. It fits either way, but I signed the execution plans and that was correct for me.

How do you see it?

Somewhere the supply air has to go. Although it would still have been nice to have known that beforehand.

How do you see it?

If there is a signed-off version of the execution plans, then such a significant change may only be made after plan modification and coordination about it.

How serious this is can only be decided if more is known (ventilation concept basement).

Is a rework still possible with reasonable effort?

I don't think it can be changed. As far as I can see, exhaust air ducts are different from supply air. But I'm just a layman. For me, it simply doesn't make sense for a basement room without windows to receive supply air. Then I could make any rooms I wanted as long as the ratio was right. The question is who knows about such things. I probably shouldn't ask the [Kontrollierte-Wohnraumlüftung Planer] or our site manager to get a neutral opinion.

The ducts do not care in which direction the air flows. The question is whether a distributor is enclosed in concrete or screed, or whether at the central unit only a bit of pipe needs to be rearranged to turn an exhaust valve into a supply valve. After all, we do not know your system and the planning.

The controlled residential ventilation planner should be able to tell you why he decided this way and what can still be saved. The construction manager, on the other hand, is your contact if you want to get rid of the information that you want a construction as planned.

By the way: The argument about the kitchen is not wrong. Turning the windowless storage room into a supply air zone, however, is rather wrong IMHO. Here the planner should have sought a conversation with you.

Maybe you post the planning (anonymized) here.

Provided the distributor is accessible, the two channels could possibly be swapped, as Bieber already says. This would have been wise anyway, given the known desire to later carry out a change of use of the rooms, to ensure accessibility for swapping later.

In general, the ratio has to be correct and then you place exhaust air in "smelly" rooms and supply air in living rooms. For you, it is the other way around now, but the desired later change of use certainly doesn’t make it easier to decide. Now it is the wrong way round; if a kitchen were to be installed there, however, supply air would be wrong, as the odors would then be drawn through the hallway to the exhaust air.
How dramatic this is is debatable. This also applies to your current state: actually supply air in the storage room is not necessarily correct, but I also don’t see this as a big drama – or do you expect odor formation there?