Which downdraft vent? For a new kitchen? Who can recommend something?

Looks like our Bora and what you describe in terms of function sounds the same.

We have a downdraft extractor from Gaggenau. In my opinion, it is very slim and hardly noticeable between the two cooktops. The control panel in the middle is for the downdraft extractor above it. It works well and delivers its performance. Regarding boiling over: inside the duct, the exhaust air is drawn off sideways and not from below. There is only one insert there, meaning if something boils over, it flows into the removable insert that fits into the dishwasher (time required to remove approx. 15-30 seconds). The two-hour conversion time mentioned above in a post probably refers to the installation of the complete system

Please show a bit more of your kitchen. Even the snippet alone looks amazing

I still have a few questions. We are also planning with a cooktop with an exhaust system (ventilation). As a precaution, we installed a 200 mm flexible duct (including insulation) a few days ago. Although I have read that most have a 150 mm connection, I hope that the 200 mm will make it even quieter. Since the cooktop is in the island, there will be three bends with a total length of about 5m.

As you can tell from the following questions, I have only dealt with this rudimentarily so far.

Do I only put a flap at the end (house wall)? Should there also be a fan installed there? Does the cooktop have a signal that can be passed on to the external fan? Do you have a test function to check if a window is tilted open? A suction power of up to 700 m³ per hour is not exactly little.

Hello Sichtbeton82,
take a look at exhaust air wall box
Usually, an additional signal device is necessary because of the window.
I also know solutions where there is additional draft.

... who recommended spiral ducting? For extractor hoods, one should use as smooth ducting as possible. And of course an external wall box. Additionally, the supply air should also be planned during the construction phase.

We have the Berbel Downline cooktop in recirculation mode, works very well!