Open kitchen without external exhaust recommended? What do you think?

We also have an island and the exhaust air goes outside through the floor! We have a 25cm floor construction including insulation and a 10 cm high flat duct simply disappears in the floor under the insulation and the screed!

Does all that work without problems? We have planned it the same way or currently the flat duct, which is 9cm for us, protrudes 3-4 cm from the floor slab because we only have 16cm floor construction. The kitchen installer said that would be more than enough... Did you cover the duct in any other way or put the insulation and screed directly on it?

Please explain that again. I did not understand.

Maybe it is technically not possible if you have a chimney, controlled residential ventilation, and an exhaust hood? The chimney sweep told us that the pressure switch would trigger an alarm as soon as the exhaust hood is in operation.

To everyone again who has an island solution with recirculation: aren't the cooking odors significantly stronger there than with one with exhaust air?

I only know the Cook Islands from acquaintances. Here, I don't find the difference between very high-priced recirculation and exhaust air to be significant. However, I have not yet fried any green herrings there.

On the island, downdraft convinces me more.

Downdraft only means that the air is sucked down directly at the stove. No statement is made about exhaust or recirculation air, as far as I understand.

I imagine that the increased crossflows over islands are stronger with altitude. Therefore, I favor downdraft there – regardless of whether it is [Ab-] or [Um-].

At wall lines, I find it a waste of space.