Real price for single-family house, possibly turnkey

yes, but somehow you must have come to this thesis. You don’t just say that like that.

And aren’t you confusing something there? Maybe airtightness and thermal insulation?

Aren’t both related?

Hi,

Can't both go together?

No.
A house must be airtight to prevent ventilation heat loss. Moreover, no warm, moist air should enter the construction where it might condense.
This airtightness is important and cannot be achieved with insulation.

Regards

Hi,

No. A house must be airtight to avoid ventilation heat losses. In addition, no warm, moist air must enter the construction where it could possibly condense. This airtightness is important and cannot be achieved by insulation.

Regards

Then we are already on the same page. Without having looked it up now, but if I’m not mistaken, there is something about building airtightness in the Energy Saving Ordinance, right? And that’s what I mean. On the one hand, the house must be airtight because it is required by regulations, and on the other hand, you need a ventilation system or you just blow the energy out the window through shock ventilation so that no mold forms.

Without having looked it up now, but isn’t there also something about building airtightness in the Energy Saving Ordinance, if I’m not mistaken?

You’re not mistaken

On the one hand, the house has to be airtight because that’s what the regulations say, and on the other hand, you then need a ventilation system or you just blow the energy out the window when you ventilate quickly, so that no mold forms.

What’s wrong with that? Controlled ventilation is the keyword.

It doesn’t help you if you insulate your house and there is a draft through some holes like crazy. If you want to save energy, you have to insulate and avoid heat loss through ventilation. And then, of course, it is necessary to ventilate in a controlled way. Blowing energy out the window has nothing to do with it.

From a purely technical perspective, there is certainly nothing wrong with it, it just seems paradoxical. The question is where the purpose of sealing and insulating the house ends and the nonsense, also from a financial point of view, begins. But to calculate that in detail, there are brighter minds than I am.
I have already expressed my opinion regarding [KfW] etc. further above. I see no point in spending tens of thousands of euros just to reach some standard whose costs will no longer pay off.

I see no point in spending tens of thousands of euros just to achieve some standard whose costs will no longer pay off.

That is basically not wrong. Energy saving must be economical and should not be practiced at all costs. However, I consider the airtightness of the building envelope necessary and correct, not only in terms of energy savings but also from the perspective of building physics.

Regards