KfW 70 without ventilation system

Exactly...(I also meant the thing with the 2 pairs of shoes)

But a post from someone in the topic "see headline", who doesn’t even have a Kfw 70 house, but claims it would work without much ventilation, is quite odd. And without the corresponding airtightness, KFW 70 is not KFW 70. It’s not about how well insulated the building is when ventilating, but how airtight the building is. Ask some experts who also perform blower door tests about building damage due to air leaks (e.g. from constant condensation in places where a lot of moisture doesn’t belong...). As an example, my current old apartment: I don’t ventilate at all (only occasionally the toilet, but not in winter after showering, brr). Still no mold anywhere. Sure, you can also manage without controlled residential ventilation, but some kind of ventilation is required for corresponding buildings, even if it is window rebate ventilation. Besides, it’s not about construction drying with controlled residential ventilation.

Sorry, I just don't believe you that airtightness is now the definition for KFW 70...

Sorry, I think you don't understand what this thread is about.

Now, unlike you, I have addressed the title. Everything else may be nice to have, but it is not binding.. You seem to have massive financial interests in the topic... judging by your posts.. But I am stepping out again now, carry on blasting...

Of course, a ventilation system is not mandatory... But anyone who has a truly airtight house can hardly expect the moisture to be perfectly managed by ventilating just once a day.

Now, unlike you, I addressed the title. Everything else is maybe nice to have, but not mandatory.. You seem to have massive financial interests in the topic... if you read your posts.. But I'll disengage now, carry on blasting...

Very interesting, but I work in such a different industry that I wouldn't know how to make money with a ventilation system. By the way, we only responded to your slightly aggressive posts ("headline"). Just take a look at the KFW Bank's website and read the documents for Kfw 70. There you will find that airtightness is an essential component of such a building, and only with the appropriate evidence is a house considered a "KFW 70" build. Without proof - no KFW 70. You apparently don't know (no proof!) whether your place is airtight enough. So your response here in the thread that you don't need a ventilation system because you manage with just airing once is misleading, as there is no KFW 70. This is not criticism of you or your building (it's good that everything is okay with you!), but it is about the fact that the statement could possibly put others in an unfavorable situation for them.