Construction costs single-family house offer realistic?

Thank you already for your comments ;)

Regarding the situation: towards HN.

Painting and flooring work can be included for an additional charge. Especially with the flooring work, we can install a significantly higher quality floor ourselves at the same cost. Of course, this involves own labor (hours) which is opposed to the pure costs.

Regarding the basement: Everything is included except the white bathtub [Weiße Wanne] as we currently do not expect it to be necessary, and earth removal. Currently, no one dares to provide a cost estimate for this.

Electric shutters are possible in the offer for an additional charge, although we currently want to obtain them separately....

If HN, and including [Keller], then cheap...

The straps are inside the interior and the roller shutter box is insulated and located inside anyway. Where should there be a thermal bridge if a strap pulley is operated inside instead of a switch? The GU just wants to earn more!

We also deliberately had straps installed (despite empty conduits and wiring). Saves electricity, saves installation costs, is sportier and on top of that more nostalgic, as we have wooden sash windows and wooden window sills installed inside anyway.

Maybe he meant built-in strap rewinders. According to the GU, they wouldn't have worked for us either because too much wall would have to be removed.

But I can recommend using electric drives for the roller shutters. That is something that is difficult to retrofit later. We also initially considered using straps. Fortunately, we decided differently. If I imagine having to operate 10 roller shutters by hand every evening and every morning... I probably wouldn't do that. Better to save elsewhere where retrofitting later is unproblematic (toilet, furniture, etc.).

Too little detail. But at first glance, sounds somewhat realistic with €2,800 / sqm.

He is talking (in my opinion) about 160 sqm including basement! So 160 living space and about 80 usable space, with one room to be heated. Difficult construct. Price not realistic, the €450k.