Retrofitting external air supply for chimney

and if the residential ventilation is turned off, would that be ok? And what about the exhaust air from the cooktop?

Then you still need a window contact switch that allows you to operate the hood only when the window is open.

However, the shutoff for the residential ventilation must work automatically. You could forget it, and in an emergency, it would only be possible for you to leave the house horizontally.

People in the forum have already said here that your chimney sweep did not require all this, so first order the chimney sweep. But with us it was the same, only approval with a certified chimney and pressure guard. It doesn't cost only 500€ either and you can hardly have it installed afterward, unless you lay the cables through half the house...

you are all right... probably taking it too lightly... I will ask my Schorni, I can keep you updated on what comes out....

you are all probably right... people probably take it too lightly... I'll ask my chimney sweep, I can keep you updated on what comes out....

Maybe you'd like to share your result here as well

https://www.hausbau-forum.de/threads/kwl-kamin-abluft-fuer-Küche-funktioniert-das.37062/page-6#post-448915

I'm also waiting for feedback from my chimney sweep...

So for us, the following was sufficient. However, we only have a recirculation hood

Certified chimney
Co detector
We have a 110mm pipe from the house to the garage through which the air can circulate. Therefore, it is not possible for the system to create a negative pressure, as it has access to outside air via the garage.