Is KfW 40 possible with 36.5 Poroton?

Hello everyone! I am wondering if it is basically possible to build a Kfw 40 house with 36.5 Poroton. Of course, provided that the rest meets the requirements. Thanks in advance. Regards

So I can only speak from my own experience. Where the basement already had better values than the exterior wall. Definitely not with a T8, the lambda is just 0.21. As far as I vaguely remember, the requirement for [Kfw40] is somewhere around 0.175.

Windows were somewhere around 0.85. Windows, I believe, go up to a maximum of 0.76 or 0.72 and would already be Passive House standard. Front door 0.91, etc. In the end, all values were better than required except for the exterior walls. Here it was a close call.

Thus, only [Kfw55] was achieved.

Poroton filled with perlite / insulation wool / wood or only with air chambers?

I am wondering whether it is basically possible to build a KfW 40 house with 36.5 cm Poroton.

I haven’t gone through your other thread – where you were still talking about KfW55 – to see if it was already mentioned to you there – but: if you read around a bit here, you will regularly come across the note that KfW40 is in most cases a futile endeavor.

Poroton filled with perlite / insulation wool / wood or just with air chambers?

That wouldn't matter at first.

Without additional insulation, to my knowledge, it does not exist. If you want to work without additional insulation, you normally need 49.5. If I am not mistaken, there are now also the first 42.5 ones that would reach the KFW40 standard. But there are only one or two stones like that. They are also filled with mineral wool or something. But the 36.5 ones definitely do not make it, to my knowledge.