Single-family house on a south slope, floor plan approx. 160m² - with basement and garage

that we will build all exterior walls in solid visible wood.…

O.K. More information is needed here. You spoke of wall heating and visible wood walls. Presumably inside. That contradicts itself. Have you also thought about how you want to accomplish the electrical installation in visible wood walls? It’s possible, but insanely complex. (We have a solid wood house with visible wood ceilings and partial underfloor heating and wall heating). Our walls came with pre-milled channels and holes for the technology, then drywall on top. Solid wood outside somehow only works as a log house. But I don’t see that. I see plaster outside (we have that too).

There is KFW 55 EE - KfW 40 plus does not exist as EE and has thus become even less attractive than it already was. Build KFW EE - we had similar discussions with the architect regarding costs vs funding. I find the cost estimate ambitious. And: don’t let yourself be dissuaded from your 3 floors - even if a few suspicious ones (always the same) would like to see 2 floors (not to mention that you would then have to accommodate 70 sqm somewhere "upstairs" additionally ;) )

Oh yes: I think 200sqm should be enough for most ;)

Due to the elaborate construction method, I do not believe in the budget.

even if a few suspicious ones (always the same) would like to see a 2 built (aside from the fact that you then have to accommodate 70 sqm somewhere "upstairs" additionally ;) )

Yes, because experience simply remains. You don't have to jump between good or bad with your opinion.
The OP asks, you give an answer! The OP asks again, you explain.
It is not always all "great and fantastic" and "I like it" like on FB.
I could also say: the nitpickers here don't want anyone to improve through the forum.
And anyone who says the house looks really good from the garden side should inform themselves about what a nice hillside construction looks like. Certainly not like this.
By the way, the necessary 70 sqm can be accommodated in the existing attic. It's there anyway.

Thanks again for the many contributions.

If you want a wooden facade, then the planner didn’t get that info.

That is correct so far. It will be considered in the next draft. The wooden facade is possibly only on the upper floor. The rest will be plastered.

Whatever that is supposed to mean (?) -> attached is a picture

Otherwise: if you like it, then everything is fine. We won’t make progress if everyone questions the long way to the garden, but you have a long fuse regarding this.
Because ultimately, most here are saying that it will be strange and inconvenient in everyday life as it is now, and it’s a bit of a shame for the garden and the money invested in such a house.

We don’t have a long fuse. We have understood the problem and will definitely think about it again and also think completely "anew."

With photovoltaics and the construction method, the step to KfW40(+) is not far. I would have it calculated by you…

KfW40(+) without ventilation? But we will definitely sit down with the energy consultant and calculate that.

Okay. More information is needed here. You spoke of wall heating and visible timber walls. Presumably inside. That contradicts itself. Have you also thought about how you want to handle the electrical installation in visible timber walls? It’s possible, but insanely complicated. (We have a solid wood house with visible timber ceilings and partial underfloor heating and wall heating). Our walls came with pre-milled channels and holes for the technology, then drywall on top.

Here you can see an example of the wooden wall. There are now a few systems that can implement the solid wood wall very well without glue and plastic.
During detailed planning, the electrical system is taken into account and the channels are pre-milled. All good. Wall heating goes on the interior walls (wood stud). Works as well.

I could also say: the “good finders” don’t want anyone here to improve through the forum.

And we do want to improve. That’s why we asked here for opinions. I really thank you for the open exchange.

The necessary 70 sqm can by the way be accommodated in the existing attic. It’s there anyway.

I’m not sure if I understood you correctly here. Where are the 70 m² still available in the attic?

The planning was done by an architect of a construction company. Here you are probably right that a standard house was somehow combined with the basement and the slope. We have commissioned a "freelance" architect as the next step and will revise the planning. Of course, without showing him the existing plans. I am curious what will come out of it. We are definitely still mentally flexible.

Why do you use wooden studs inside?