House Construction Cost Estimation - Does this fit?

Price difference of approx. 8k gas heating to 35k heat pump

What is happening on the market right now is also far from any reason. Like at the beginning of 2021, when the running meter of 4x6 roof battens rose from €0.6 to €2. Adjusted for the costs of the gas connection, a standard heat pump in a new building should not cost much more than €5-8k extra.

ProTip: on Kleinanzeigen there are now young home gas boilers with solar thermal and buffer tanks as a complete package for €3-5k. By switching to a heat pump, it should certainly be possible to negotiate the price well.

(and the number is shocking me right now, but is it unrealistic because of that?)

That doesn’t shock me at all. The house size is far from “normal” house sizes for 4 people.

What’s going on in the market right now is also far from any reason.

Well, you do have the option to somehow counter the exorbitant prices with adjusted house size. Already 10 years ago people considered leaving out the basement. Here you even have an expensive extra on top, if you basement the garage and add an attic.

P.S. I would have calculated with T€ 3 for the living area and T€ 100 for the basement + T€ 50 flat incidental construction costs + T€ 50-70 for the double garage. Outdoor facilities etc. on top ==> so T€ 800 + outdoor facilities Fits well with the "sister-in-law" in the other thread.

I’m also roughly there: 600,000€ living area 150,000€ basement (including the garage basement) 60,000€ double garage 50,000€ incidental construction costs Plus outdoor facilities … so just under 900,000€

Price difference of 8k gas heating to 35k heat pump (approx.)

If you want to save, then somewhere else, but not on the heating that will eat your hair off your head. By the way: unfortunately, you can’t see the generous 200 sqm in the design, nor is it practical. When I see the door position variant of the children’s rooms upstairs, which is actually installed in the rather narrow space, as well as the dark corridors and the small utility kitchen, it leaves me speechless.

I also find the dressing room, which is not accessible from the bedroom, very amusing

How rural is it? Just tell me the region. Since the property was very affordable by today's standards (if no purchase from family), I would guess "very rural." If there is a general contractor on site of the old school, I would therefore estimate roughly 700k for those parameters.

I find this "Guess with Rosenthal" rather inappropriate. ... why don't you simply write what was offered to you, with what scope of services, and then ask for experience, whether it is realistic or not. The information you are gathering now .. if I remember correctly from about 650 to 1,100 thousand euros won't get you any further.

I also find very amusing the dressing room that is not accessible from the bedroom

My highlight was the opposite narrow toilet where you can hardly pass the washbasin. :P
We're also building a Non-Bauforum-Approved floor plan, so I really shouldn't complain. But this one genuinely still has a few obvious potentials that can also be quickly improved.