Ventilation / airing in the passive house - duct odor / musty laundry

The laundry from the machine or laundry in the room? (..) Is there a bathtub in the bathroom?

When opening the machine, a musty smell already wafts out, and when the weather changes, the affected bathroom also smells like a sewer, even when the washing machine is not running. There is no bathtub in this bathroom. Only a toilet, shower, and sink. We already refill the siphons prophylactically with a sip of water.

My question, however, is more about whether a missing ventilation and exhaust system is normal in a passive house and whether this small ventilation within the room is sufficient at all. In all the "normal" houses around us, considerably thicker pipes protrude from the roof. And in our house, a toy-sized vent for the whole bathroom is supposed to be enough? I can hardly imagine that.

Hmm, does the toilet flush at your place always empty all the traps?

In my opinion, at least one ventilation and exhaust air duct must be routed over the roof (primarily at the main downpipe).

And yours in the bathroom is only a vent (may also be used additionally on secondary downpipes).

But that is independent of [Passivhaus].

Caspar2020 is absolutely right. A pipe must definitely be routed above the roof according to DIN to vent the pipes. If that is no longer possible because it cannot be done technically afterwards, I would try it with a so-called "Durgo". It would not be DIN-compliant in practice but it has been installed countless times and it works.

I see at least two separate problems. 1. the missing or insufficient ventilation of the wastewater. 2. the problem with the washing machine. Wastewater never flows back into the washing machine, the musty smell of the laundry has nothing to do with the non-functioning ventilation.

I suspect there are also two independent problems here that just happen to coincide: 1. Poorly executed ventilation of the sewage system 2. You probably generally only use liquid detergent or color detergent. At least occasionally use powder detergent - for example for white laundry and towels. Especially towels are usually suitable for 60 degrees, which you should also take advantage of. But not with the eco program of the washing machine, because it does not reach 60 degrees. At least occasionally use the 60-degree normal program (with powder detergent).