Financing land and house? Taking out a mortgage? Construction costs?

Garage has saving potential but is not unusual and certainly not a prestige object

My mistake. The last post referred to electricity and sockets. Depending on the floor plan, a garage would make sense.

Sorry Zaba, I just lost my temper calling the house a prestige object

I am quite surprised by what some people call "unprofitable." Perhaps my intention was partly misunderstood. It was not about looking for arguments against anyone, but about an assessment of the costs and financial feasibility, as mentioned at the beginning.

Outdoor sockets and garage are extra, 80 sockets are "only" inside.

I am surprised by what some people call "unprofitable".

That is not surprising at all if you have known the forum members here for a while. For the colleague HilfeHilfe, I have already set up a chauvinistic piggy bank on another occasion, and he skillfully and with pleasure keeps throwing in a Heiermann every now and then. Each according to their ability. Take it with humor!

Out of interest: You said you now know what you are doing? What exactly? What has changed compared to before?

I'll give you my two cents:
Shell construction with plaster and screed 150,000 (incl. groundworks) => I find this relatively high, considering that plaster and screed cost less than 40k€ and you have drywall in the upper floor. I would get another offer here. My feeling tells me that you could come out about 10-15k€ lower.
Roof 40,000 => I'm not really familiar with 1.5-storey houses. But we have a cold roof with 24cm ceiling insulation on the upper floor (invoice paid 2 weeks ago 20k€). Also, I assume parts of the drywall are included here. So get a 2nd or 3rd quote.
Drywall 30,000 0 => I can't judge, I have no drywall.
Wood stove 10,000 => Wood stove and chimney or do you mean such a Schiedel solution? If Schiedel solution (chimney and stove in one), then the price fits.
Windows, doors (wood-aluminum with venetian blinds) 50,000 => As my predecessors said, just downgrade to plastic. We have many windows over 140sqm + sliding lift door + colorful. Invoice 20k€ without interior & exterior door.
Sanitary 40,000 (air-water heat pump, underfloor heating, controlled residential ventilation) without sanitary fittings (we buy those ourselves and have acquaintances install them) => This is a bit tight. Keep 5k€ in mind as a buffer. I suspect that things like outside water tap, laundry basin in the utility room, fridge line are not included. Also, in my case, sanitary fixtures cost only 20% more at the specialist trade (compared to online). That's potential savings, but what are 2k€ on 10k€ for a whole house?
Tiles 10,000 (this is still estimated, offer not yet available) => Uh... since I don't see any flooring position here, I assume a lot will be tiled. I predict now that you will be sick of it and expect 15-20k€.
House connections 10,000 => Fits, possibly -2k€.
Garage door 4,000 => No idea.
Statics 2,400 => That's okay, I paid less. Why your husband has no connections here is beyond me.
Kitchen and carpenter 20,000 (estimated)
Electrical 16,000 => Could fit. You just have to hold back.
Steel stair railing 3,500 => Fits.

And now the possible missing items. What about..?

- Surveying
- Construction site setup (construction road, toilet, electricity meter, etc.)
- Removal of excess soil and disposal
- Construction electricity/construction water
- Scaffolding (often has to be set up twice)
- Window sills inside/outside
- Drainage (inspection shafts, cistern, etc.) and civil engineering
- Energy consultant required for KfW55
- Painting work
- Soil and ground survey reports (are 2 items)
- Exterior facilities (incl. driveway, paths, terrace, fence, plants, bushes, trees)
- Garage/carport
- Landing
- Front door canopy
- If you don't downgrade after all, there will be additional land registry, notary costs.
- Move
- Furniture/furnishing

If all that is clarified, your list would actually be complete.

KNX is still a big exotic, also because of that and not only because of the costs. For standard use, you don’t need it; it runs very well and stable over Wi-Fi.

An industrial LAN wiring or KNX is needed by very few single-family houses.

Thanks to MESH, Wi-Fi is even faster and more stable throughout the whole house.

And there is nothing against a few LAN sockets, as said, minimum one per floor. But LAN is very expensive with electricians and therefore offers good saving potential!

You have absolutely no clue