Extractor hood with exhaust air at KfW55

Exhaust air without further measures (such as the above-mentioned thermal box) will not work because you will fail the BD test. For KfW55, a maximum air exchange rate is prescribed which you can never, ever meet with a 150mm large hole (a 1cm large hole would already be problematic!)

But as already mentioned, if I were you, I would ask myself whether it has to be exhaust air at all. A good hood in recirculation mode with an activated carbon filter is not significantly less efficient.

Muldenlüter as well. We really cook a lot and sometimes with a lot of fat (just tastes better). Great sense of space. Of course, the controlled residential ventilation also pulls additionally. But unlike the condominium, we have never(!) had strong cooking odors. (annoying! Cooking basically smells good). Nevertheless, KFW is just a calculation. And 55 should be achievable despite exhaust air. I am a complete layman since we built without financing, but we did have an energy consultant. He explained that it's all just a calculation.

Thank you very much for the contributions. I had also thought about a downdraft extractor, e.g. Bora, but that is another price range and I cannot fit this downdraft extractor on a 60 cm deep countertop.

Apart from that, a recirculating hood has nothing to do with exhaust or recirculated air. Both are possible.

Apart from that, a downdraft extractor has nothing to do with exhaust or recirculation air. Both are possible.

That is correct. I wanted to say “even” with a downdraft extractor. Because it is often said that it performs worse than a hood. Regardless of recirculation or exhaust air.

I think fan-forced always stinks and you have smoke anyway when searing steak etc.

Exhaust air pulls the dirt outside and that is simply much better. If you want to do a lot of pan frying, exhaust air is definitely the better choice.

We have Miele fan-forced and cooking odors are already very noticeable despite the activated carbon filter.