Optimization of floor plan for detached single-family house 155 sqm

Sure, that was obviously exaggerated, but there is still a lot of room for maneuver between these extremes, and I could only start if I were really satisfied with it and would also like to build it that way. Actually, I would have tried the table further over there, really centered opposite the entrance, and the window wider. As I said, these are just rough ideas; the floor plan experts can surely say more about it, but this way it would be more comfortable for me than the cramped seat window version. Can you draw it like that, directly opposite the door and with a wide window?

What is the actual strength of the marked "visible wooden beam" with your usual ceiling height of 250cm?

Actually, I would have tried the table a bit further over there, really centered opposite the entrance and the window wider.

Ah, now I understand. But then the window is really off-center. Or the table is not centered to the window. Both strange in my eyes.

What thickness does the drawn, "visible wooden beam" actually have with your usual story height of 250cm?

Unfortunately, I don't know. I am also missing the detail of how/whether the staircase will be visible in the kitchen on the ground floor. I still have to ask about both.

Small update: we have now painted 3 windows and the seating window as well. Both fixed glazing panes will now receive a wooden windowsill as our own work.

This saves us a good €6,000.

But the kicker came with the ventilation system. Instead of the Tecalor TTL 4.5 ICS TSBC eco, we are being offered a combination device. The heating and ventilation unit THZ 5.5 eco comes with a surcharge of a whopping €21,000. I cannot understand this price difference. But since we are tied to the supplier, we cannot get any further offers. Therefore, we will most likely do without ventilation. In theory, the insulated attic should at least allow the possibility to centrally ventilate the upper floor later, right?

But since we are tied to the provider, we cannot obtain any further offers.

I don’t understand. That seems a bit naive to me. What prevents you from buying the device later? What does the contract say? That you are only allowed to buy from this provider forever and ever? That would be ridiculous.

In theory, at least the insulated attic should allow for later central ventilation of the upper floor, right?

What does your theory actually look like? That will never work.