Decentralized ventilation system that is hardly visible on the exterior facade

Is that really so? And how much money are we talking about? We are still at the very beginning when it comes to ventilation, and I am currently overwhelmed by all the information and opinions...

Decentralized ventilation for the average single-family house costs about T€ 2.5 plus installation (each with core drilling or suitable insulating stone) and a few additional power lines to the devices. Centralized is rather factor 2, but also higher installation costs. I find decentralized good (I am installing it myself in my renovation), but for new builds I would install centralized. It's just a little better. Both can ventilate properly, though.

I do not find decentralized good for a single-family house. For decentralized, you calculate about 1000 euros per device including installation. A normal single-family house requires about 6-8 units, so you are at about 8,000 euros. A central system is currently sold for about 12,000 to 18,000. So the factor 2 of my predecessor is correct.

we deliberately decided against central ventilation, but that should not be the topic here)

May I ask why? A makeshift solution with an individual workaround for the outlets is quite counterproductive after all.

I don't think decentralized is good for a single-family house.

May I ask why? What is the advantage of the central system compared to a decentralized one? If it is relevant: We are building a single-family house with two separate residential units (one floor each).

May I ask why? What is the advantage of the central system compared to a decentralized one? If it is relevant: We are building a single-family house with two separate living units (one floor each).

Central has much quieter operating noise, no holes in your exterior walls (noise from outside), easier to keep clean (just regular filter changes), much better ventilation performance and heat recovery. Simply controllable via app. There are also decentralized solutions that try to compensate for some of the disadvantages. It's just a poor low-budget solution. I would rather skip it altogether and ventilate manually.

Regarding the question: Such "holes" can be creatively hidden or turned into features through the facade design. How should the facade be?