ᐅ Open kitchen: exhaust air or recirculation with controlled residential ventilation & KfW 55 standards

Specki schrieb:

How is it supposed to affect the mechanical ventilation system? It doesn’t care at all.

Well, it continuously tries to balance the supply and exhaust airflows to have equal air volumes (for example, 120m³/h (70.6 CFM) out and 120m³/h (70.6 CFM) in). If an additional, very strong exhaust airflow occurs, this balance is disturbed. Correction is only possible to a limited extent with standard mechanical ventilation systems, which typically reach their limit at 300 – 400m³/h (176 – 235 CFM).

So for us: there is also recirculated air through a downdraft extractor (mainly to remove water and grease in the charcoal filter, not to reduce odors), and the mechanical ventilation runs at a higher setting in the morning, midday, and evening, allowing odors to clear out more quickly.

Because the fresh air supply is arranged in living and sleeping rooms, kitchen odors cannot reach those rooms. Fresh air always enters these spaces. Air is extracted from the hallway, utility room, kitchen, and bathrooms, so kitchen odors tend to concentrate there (for us, they are mainly noticeable only in the utility room and kitchen itself).

fragg schrieb:

I seriously cook a lot and enjoy it, nothing ever smells bad in my kitchen.

I'm not talking about boiling pasta or using a Thermomix.

Bookstar schrieb:

I'm not talking about cooking pasta or using a Thermomix.

A specific example where an extractor hood from the last century is actually useful.

My child likes pasta, and I don’t have a Thermomix.

That’s subjective anyway. If you fry fish and an hour later someone who didn’t eat with you enters the house, they’ll say, “Did you have fish?” regardless of whether you used a convection fan, exhaust ventilation, or anything else.

micric3 schrieb:

- Who chose a recirculating hood instead of a vented exhaust hood, and why?

We chose a recirculating extractor hood from Falmec, model Marilyn, because we liked it and the simple ceiling construction in that area did not allow for concealed ductwork. A vented exhaust system would have required a downdraft extractor, which wouldn’t provide free-surface induction. Contrary to my concerns, the hood’s odor reduction is sufficient for us.

micric3 schrieb:

@opalau: You are one of the few here who opted for exhaust ventilation. Do you have a mechanical ventilation with heat recovery system installed? Have you planned for separate supply air, or how do you plan to manage that? What about thermal losses through the wall box (when not in use – a hole remains a hole, hence the question)?

We have a mechanical ventilation with heat recovery system but initially do not plan to use separate supply air. I will observe how it performs in practice, what the ventilation unit (Zehnder 450) indicates, whether it requires opening a window, etc. We also have a relatively large space of about 230 m² (2,475 sq ft) with an insulated attic. Our exhaust wall box is insulated (Naber Thermobox).