Exhaust air in the bedroom - supply air in the storage room

Depending on the selection, the user of the bedroom will enjoy the smells....

And why should that be so?! For one, he does have exhaust air in the bedroom, and for another, the exhaust air becomes outdoor air after passing through the heat exchanger; with plate heat exchangers, it is technically impossible for the exhaust air and supply air streams to mix. And even with rotary heat exchangers, the “crosstalk” from exhaust air to supply air is more of a theoretical nature. So where does this assumption come from? Or did you mean that the incoming air is “contaminated”? Without knowledge of the floor plan, that is initially speculation, since it is not even certain that the rooms are close together, and even if they are...

It’s about the ‘stinky air’ in the room where the supply air comes in and not about the supply air itself. If the exhaust air is in the bedroom and the supply air is in the bathroom, and you put a Kaiser in the toilet, then the smell of it, following the negative pressure, migrates into the bedroom. The same would apply if he stores smelly things in the storage room. Then THIS stench migrates towards the bedroom.

Technically, it doesn’t matter; the only important thing is that supply air is present. The direction doesn’t matter. And if normal things that people typically have are stored in the storage room, then it’s also not a problem in terms of smell.

Therefore, I would take it easy and put it on a list; if you ever need something, you can draw the card.

if there is exhaust air in the bedroom, the nice toilet smell just passes by there. but that's all. if no one goes to the toilet heavily at night, there won't be any problems with it.

however, there are completely different problems: KFW! if you build with kfw, the correct function of the ventilation system is checked in the end (do you have a kfw assessor?). he will of course criticize such a replacement and insist on improvement. otherwise kfw is quickly over...

But it takes a conscientious KFW snoop to notice that

So we should keep the church in the village. KfW what else? Ideally, the building authority will also come by and impose a construction stop...

Isn't it still too early for April Fools' jokes?

It’s about the ‘stinky air’ in the room where the supply air comes in, not about the supply air itself. If the exhaust air is in the bedroom and the supply air in the WC, and you put a diaper in the toilet, then the smell from it will follow the negative pressure into the bedroom. The same would apply if he stores smelly things in the storage room. Then THIS stench will travel towards the bedroom.

I wouldn’t want to rule that out, but as I already wrote, without knowing where the rooms are located and what air volume change is used, it’s hard to assess. Only one thing: a controlled residential ventilation system is not an extractor hood, i.e. the volume flow is very low, especially in a storage room, rather a low air change rate will be set. If the entire volume of the storage room is exchanged two to four times per day (which should be enough for such a room) and mixes via the overflow area with all adjacent rooms, I would assume that the OLF concentration drops quite quickly. If the storage room was directly adjacent to the bedroom and was the only one to overflow into the bedroom, I would consider that more likely. There are just too many ifs for me.

And I’m not saying that this would be correct from a planning point of view or that it wouldn’t be a defect. I’m only trying to calm the OP down a bit instead of spreading hysteria.

And if the OP actually perceives onion odor in the bedroom at some point, they will have to adjust the use of the storage room accordingly. But that doesn’t make the house unusable or uninhabitable. It’s annoying, though, because you ordered something different.