Construction costs are currently skyrocketing

Thanks already.
We have installed a really cheap recirculation hood in our rental apartment, maybe that's the reason.
Which ones are recommended? Bora system?

If we make changes ourselves, do I then lose the builder's warranty?

We had Bora recirculation in the first house, combined with a controlled residential ventilation system. I would do it again anytime. No deposited grease like you know from cheap hoods, nowhere.
We are building it exactly the same way in the new house again.

:eek: my phone types too slowly. ... you are damaging the building envelope and the airtightness is gone for the BT. Instead of the Bora, we have one more empty cabinet for us, a recirculating hood, and a surface induction cooktop with 6 cooking zones (from the brand manufacturer)

We have an extractor fan in the wall cabinet. Miele with 12-fold filter, has so far been able to extract everything well, even when cooking ground meat, and there is no smell. Previously, in the apartment, we only had interior walls in the kitchen and a cheap recirculation hood, where most of the air passed by at the front. Whether to vent upwards or downwards mainly depends on the rest of the kitchen. If you are putting wall cabinets above anyway, it is also good to vent upwards. With an island or peninsula, rather downwards.

The builder will, of course, blame all problems on your core drilling if in doubt.

With a good recirculation hood and daily cooktop use, you can change the activated carbon filter every six months. It costs money and is not necessarily sustainable.

The exhaust hood blows fat, odor, and water vapor outside. Which brings us to the topic, because cooking produces a lot of water vapor. If it is not expelled outside through the exhaust hood, it has to be ventilated out of the house.

You don't have to operate your exhaust hood at 500m³ per hour; there are generally several settings.

I find it strange how you can build a house and then use a recirculation hood, like in an apartment... the exhaust hood is exactly what keeps the kitchen clean, right? No more greasy, fatty air constantly being recirculated...

We have a cooker hood in the upper cabinet. Miele with a 12-fold filter, so far it could handle everything well even with minced meat and nothing smells. Previously in the apartment, we only had interior walls in the kitchen and a cheap recirculation hood, where most of the air passed by at the front.

You've been living there for 4 weeks, right? Just wait until the filters slowly get fuller ;)

By the way, it is also a misconception that the range hood is supposed to prevent odors. Its main purpose is to prevent vapor (water steam with fat droplets) from spreading everywhere. And at most to extract smoke (although smoke ideally should not occur during cooking). Odors cannot even be prevented by commercial exhaust systems, which have a multiple of the extraction capacity.