Is financing theory practical?

And, somewhat off-topic: Are inquiries with average income and "larger" construction projects currently increasing? Or is it just me? Or has the price just risen again?

Hm - I feel the same way. However, my feeling is stronger that average salaries are similar to earlier inquiries, but the size of the construction project has "significantly" increased. Our total project came to around 360,000 euros (including ancillary construction costs and land + ancillary costs). For 170 sqm without a basement with 2 full floors. OK - KfW70 according to the old energy saving ordinance and without outdoor area (paving, terrace, garage/carport). However, I have the impression that recently, a similar project is currently planned with 400-450k EUR + ancillary construction costs + land.

Our overall project ended up at around 360,000 euros (including incidental construction costs and land + incidental costs). For 170 sqm without a basement with 2 full stories. OK - KfW70 according to the old Energy Saving Ordinance and without outdoor area (paving, terrace, garage/carport). But I have the feeling recently that for a similar project currently 400-450k EUR + incidental construction costs + land are being planned.

When we had concrete numbers planned for the first time 3 years ago, we were also at a 380,000€ investment for everything. Today – in the concrete construction project – we are rather at 475,000€. On the one hand, land prices have increased by 25% during this time and on the other hand, the house now costs significantly more. The only thing that has changed qualitatively there, however, are the energy standards (insulation, heating, solar, etc.).

Because everything is getting more expensive, the (gefühlt) standards are also getting higher and higher... although I paid significantly less for a bigger house. But it depends on the region, the type of contract, and the EL...

Because everything is getting more expensive, the (perceived) standards are also continuously rising... although I paid significantly less for a larger house. But it depends on the region, the type of commission, and the EL...

I understand that a KfW70 house according to the new energy saving regulation is a former KfW55 house according to the old energy saving regulation. However, we were quoted a surcharge of about 7-8 thousand euros at that time for this higher standard, which was not worth it for us. We built with geothermal energy. Our plot was built into a slope (so a wall in the ground floor had to be sealed extra). We have triple-glazed windows, increased burglary protection (which was still an extra charge at that time and is probably considered standard today), electric shutters, network sockets in almost every room, a 10 cubic meter cistern, glass sliding door, lots of power outlets, etc. – meaning: we did not necessarily build to the lowest standard 2 years ago. Even if I include our photovoltaic system, we were at a total of 370,000 (including painting and flooring). If I deduct the plot + ancillary costs from this, our house amounted to 290,000 euros including ancillary costs.

I can imagine that prices have generally risen. But if the "perceived price" of 400 - 450 thousand euros excluding additional construction costs and land is correct, this would be a surcharge of about 35 - 55% in 2 years.

Well, my feeling could also be wrong or I might be reading selectively here, since the projects which seem very tight to me tend to remain in my mind.

PS: – our very first plan (before discussions) foresaw a house build for 180,000 euros for 130 sqm. We had to give up on that quite soon.

Well - my feeling can be wrong or I am reading selectively here,

No, you are not mistaken; it is no different in real life. Rhineland greetings

I can imagine that prices have generally increased. But if the "felt price" of 400 - 450 TEUR excluding incidental construction costs and land is correct, this would be a surcharge of about 35 - 55 % in 2 years.

Not that high.

Those wishing to build are getting younger and are career starters in well-paid jobs, so hardly any equity has been saved up, but the desire for a house with many extras (whether it is square meters or the fittings), which stands out from the crowd, is there.
I find a bit of reality and humility in life missing!