central vs. decentralized ventilation system

That's the thing, hardly anyone has ever experienced it. All the worse, I find, is that people who obviously have no idea badmouth something just to justify their own bad purchase.

At the beginning, we also considered using decentralized ventilation in the bathrooms for our house, since a complete central system was too expensive for us, but then we came to the conclusion that we would rather plan the windows smartly and ventilate ourselves. Even though they are not infinitely loud, roughly like a convection oven, I would say, it is extremely annoying. The moment when the ventilation is finally quiet is absolutely liberating. By the way, also absolutely nerve-wracking when bathing.

We currently have a decentralized system in both bathrooms of our apartment, one of the bathrooms is directly next to the bedroom. I freak out every time I lie down in bed after showering and the ventilation is still running on high to get the humid air out. I don't know any houses with a central system, but if they are much quieter, then definitely go for that.

In ours, I have set blocking times from 10 p.m. until morning because they like to turn on spontaneously at night. Even after half a year, I still don’t understand the criteria according to which the humidity sensors operate. Now in summer, it sometimes runs for two hours after showering despite open windows...funny enough, it often only starts when I’m already done with the shower, even though the fan is right next to the shower.

Except for the necessary planning effort for pipe installation and air volume calculation, a controlled residential ventilation system is superior to the decentralized solution in all aspects.

If home builders did not always advertise it as a super-luxury feature, it could even be price competitive. Because no core drilling is needed, no additional sockets, and not 7-10 extra devices and covers on the exterior facade.

Properly planned, you hear nothing and nothing gets dirty in the pipes.

To be honest, with new construction, a core drilling is not necessary either. There is a special stone with the ventilation pipe that is simply built in. There is no difference in work now. Ultimately, even with decentralized systems, a certain amount of planning cannot be avoided. Fans with heat recovery are always planned and connected in pairs, one ventilates inward, the other outward. If that doesn’t work out, there are also twin fans that handle both directions at once (no idea if that works well). They are definitely more expensive. What I find missing in the discussion are the outlets. In centralized controlled residential ventilation, they are usually planned in the ceiling. With decentralized systems, they are on the wall, and you cannot place furniture there. Ours in the bedroom conflicts somewhat with a wardrobe door; if you open it vigorously, the cover is closed. Of course, this can be avoided with good planning beforehand and knowing exactly where the furniture will go. But it is definitely a limitation.

I would only install a central ventilation system.

In my old apartment built in 2014, I had a decentralized ventilation system, which was too loud for me at night. Furthermore, both systems broke down after the warranty period. New purchase per device 900€. (I soldered in a new power supply, which only cost 30€. If you know what you’re doing.)

The new apartment built in 2023 also has a decentralized ventilation system. However, it stops every minute and changes the direction of rotation, which is extremely annoying -> system is deactivated at night.

In my parents' house, there is a central system that you cannot hear and also shows no mold or similar issues in the pipes after 20 years.

Are 13,000€, as stated by the thread starter, realistic for a central ventilation system?

Best regards