Now I really wonder what the flat-rate construction costs of 1800-2000€ are still worth...
In our case, solid construction Poroton without ETICS, to KfW 70 standard with air-water heat pump, KNX electrical, whirlpool, decent tile quality, parquet everywhere, and all plastering and painting work included.. But beware: depending on the demands for KNX or interior finishing, you can significantly increase the expenses here. For example, we are having 190 m2 of parquet laid, which you can buy for 35€/m2, 70€/m2 or 120€/m2 or even more euros.... A simple KNX system starts at 5000€, with no upper limit. And since we are already talking about electrical work: there is no problem buying lamps including installation for 20,000 euros for 150 m2 of living space....