Hello,
During our kitchen planning, the kitchen fitter recommended a ventilation hood with an exhaust air system.
Which is better for a KFW55 house: exhaust air or recirculation?
Advantage of recirculation: you don’t lose the heat to the outside.
Advantage of exhaust air: odors are removed much more effectively to the outside.
Is an exhaust air system even possible with a KFW55 house?
During our kitchen planning, the kitchen fitter recommended a ventilation hood with an exhaust air system.
Which is better for a KFW55 house: exhaust air or recirculation?
Advantage of recirculation: you don’t lose the heat to the outside.
Advantage of exhaust air: odors are removed much more effectively to the outside.
Is an exhaust air system even possible with a KFW55 house?
Hello,
we also debated for a long time but have now decided on a recirculating system. We will have a kitchen island with a Bora hob extractor. Currently, we have a simple recirculating hood from Ikea, and that works fine. It really comes down to priorities and how much it is worth to you.
Maybe we just don’t find the smells that bad; everyone has a different tolerance, just like with soundproofing, for example.
In summer, I hopefully have all the windows open anyway or I’m always grilling. Regards
we also debated for a long time but have now decided on a recirculating system. We will have a kitchen island with a Bora hob extractor. Currently, we have a simple recirculating hood from Ikea, and that works fine. It really comes down to priorities and how much it is worth to you.
Maybe we just don’t find the smells that bad; everyone has a different tolerance, just like with soundproofing, for example.
In summer, I hopefully have all the windows open anyway or I’m always grilling. Regards
P
Pwnage61918 Nov 2021 16:12Sorry, the exhaust vent would be located directly on the exterior wall, so only a core drill hole would be needed.
I spoke with the builder.
He said he is not "allowed" to offer this to me because otherwise, he would lose the KfW55 certification.
He explained that since a lot of air is blown outside, the building would no longer qualify as a KfW55 house on paper.
However, he also mentioned that he had the drilling done on his own property afterward.
But if KfW were to find out about this, we would have a problem.
I spoke with the builder.
He said he is not "allowed" to offer this to me because otherwise, he would lose the KfW55 certification.
He explained that since a lot of air is blown outside, the building would no longer qualify as a KfW55 house on paper.
However, he also mentioned that he had the drilling done on his own property afterward.
But if KfW were to find out about this, we would have a problem.
There is no absolute better option. You have to decide what matters most to you. Odors can also be effectively filtered with a good recirculating hood. There is actually a clear difference (and therefore a better):
If the recirculating system is part of an integrated ventilation system with heat recovery,
this can lead to problems.
Cooking fumes often contain not only water vapor but also a higher proportion of fat aerosols.
These can condense in the cooler exhaust heat exchanger and gradually clog and disable it.
This means frequent removal, cleaning in a surfactant bath, and filter replacement —
a rather unpleasant procedure!
So the answer depends on the usage scenario.
Pwnage619 schrieb:
Sorry, the exhaust vent would be directly on the exterior wall, you would only need to make a core hole drill.
I spoke with the developer.
He "is not allowed" to offer that to me because otherwise he would lose the KfW55 certification.
He says that because a lot of air is blown outside, it no longer qualifies as a KfW 55 house on paper.
However, he also said that he had the drilling done afterwards at his own place.
But if KfW were to find out about it, then we would have a problem. Mmmh... I tend to think he’s just not willing to do it. But I don’t know the full background.
If it really is a very tight situation where he couldn’t meet the standard anymore, you could explore options with an energy consultant to compensate for it.
But that won’t help you. It will probably be too much effort for him.
B
Benutzer20018 Nov 2021 17:03Pwnage619 schrieb:
He "is not allowed" to offer that to me, otherwise he loses the KfW55 certification. He simply doesn’t want to. Nothing more. A blower door certified wall box (and ideally a model like the Thermobox from Naber) should be sufficient. Unless, in your case, everything is already calculated so tightly that even the smallest thing causes everything to fail.
At least, there are no prohibitions from KfW.
Pwnage619 schrieb:
He says that because a lot of air is blown outside, you no longer achieve a KfW 55 house on paper. But he is still allowed to install operable windows even though a lot of air escapes outside? That statement is factually incorrect, as this “air being blown outside” is not accounted for in the calculation at all. The wall box is completely airtight—like the wall or the windows (or at least they should be). Only the 15x15cm (6x6 inches) core drill hole is less insulated (the mentioned wall box has a U-value around 2; for a hole in the wall, that’s already good—older windows are often worse).
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