I want to build a single-family house according to the KfW55 standard. These houses are absolutely airtight, and the airtightness is verified with a blower door test. Is it allowed to operate a range hood in exhaust mode? For the exhaust, a duct with a diameter of 150 mm (6 inches) leading outside is required. Wouldn't this area then no longer be airtight?
Exhaust air without additional measures (such as the thermobox mentioned above) will not work because you will fail the blower door test. For KfW55 standards, a maximum air change rate is specified, which you absolutely cannot meet with a 150mm (6 inches) diameter opening (even a 10mm (0.4 inches) opening is likely to cause problems).
As already mentioned, I would also ask myself whether exhaust air is necessary at all. A good hood operated in recirculation mode with an activated carbon filter is not significantly less efficient.
As already mentioned, I would also ask myself whether exhaust air is necessary at all. A good hood operated in recirculation mode with an activated carbon filter is not significantly less efficient.
Downdraft vents as well. We really cook a lot and sometimes use a lot of fat (it simply tastes better). Great sense of space. Of course, the mechanical ventilation system also runs. But unlike in our condominium, we have never (!) experienced strong cooking odors. (Annoying! Cooking smells are generally pleasant).
Still, KfW is just a calculation. And achieving 55 should be possible, despite exhaust air. I’m a complete layperson since we built without financing, but we did have an energy consultant. He explained that it’s all just a calculation.
Still, KfW is just a calculation. And achieving 55 should be possible, despite exhaust air. I’m a complete layperson since we built without financing, but we did have an energy consultant. He explained that it’s all just a calculation.
R
Raiweired28 Jun 2021 22:37Many thanks for the contributions. I had also considered a downdraft extractor, for example Bora, but that is a different price range and I cannot fit this type of extractor into a 60cm (24 inches) deep countertop.
opalau schrieb:
Besides that, a downdraft vent has nothing to do with exhaust or recirculation air. Both are possible. That’s correct. I meant to say "even" with a downdraft vent, since it is often said that it performs worse than a hood. Regardless of whether it’s exhaust or recirculated air.
I find that recirculation always smells bad, and you get smoke anyway when searing steak or similar.
An exhaust system pulls the dirt outside, which is simply much better. If you often sear food in a pan, an exhaust system is definitely the better choice.
We have a Miele recirculation system, and even with an activated carbon filter, cooking odors are still quite noticeable.
An exhaust system pulls the dirt outside, which is simply much better. If you often sear food in a pan, an exhaust system is definitely the better choice.
We have a Miele recirculation system, and even with an activated carbon filter, cooking odors are still quite noticeable.
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