Surcharge for windows according to the standard construction description

I have to agree with my predecessors and also cannot quite understand where the desire for all those floor-to-ceiling windows comes from. They take up your space and if something is directly in front of them, like a desk, you will only be able to open them fully with great effort. Cleaning will then become difficult and from the outside, it doesn’t look particularly good either. My sister used to have that in her childhood room, it was total rubbish.

Regarding the triangular window: Nobody will stand in front of your house and admire this window. It won’t be noticeable at all later on. If you want to use the attic as living space and want a pleated blind, it will also be expensive because it has to be custom-made.

I would first really sketch out my living situation in detail and with all the furniture, that is, with my actual dimensions, or represent it somewhere at home (or somewhere in a model home center), so that I can imagine it exactly. Basically according to the "FFF," form follows function. The exterior view of the house would rather play a secondary role – you live inside, and it has to function individually and optimally there. Actually, I would also forego any kind of sliding doors, as they are rather impractical for me; the mentioned 3-wing doors (center part can be folded up 180 degrees if needed) seem like a great solution. In the "old" house, we had large sliding doors and are much more satisfied with the current solution; I would definitely save myself these additional costs. The often seen piece of furniture (sofa/bed/desk.....) in front of floor-to-ceiling windows always seems like a planning mistake to me, as do the floor-to-ceiling windows here in the bathroom; for me, these are rather trendy, therefore temporary and less sensible ideas. Since construction apparently has not yet begun, I wonder whether you want to post your construction project here (including discussion of the floor plan) to maybe arrive at further thoughts about which you might regret after the construction. Often people do not want to because they perceive it as "uffff... finally done," but waking up to issues afterward can be permanently annoying.

Floor-to-ceiling window office ... I would fundamentally reconsider the window position. As it is now, the office is basically a mini room with a hallway from the entrance door to the floor-to-ceiling window. Why not a window on the top wall, why the floor-to-ceiling window? What purpose is it supposed to serve?

Here, I have deliberately limited myself to answering the question posed by the OP from my background as a former window manufacturer and later a dealer. I consider the design to be a loveless quick job by a drafting slave, but I didn’t want to open that can of worms. Nevertheless, I have to completely agree with you that the office is a storage room with a pleasant-sounding label written into the floor plan and/or a window that is positioned in an incomprehensible and nonsensical way.

Actually, I would also avoid any kind of sliding doors, as they are rather impractical for me; I find the mentioned 3-leaf doors (middle part can be folded 180 degrees if needed) a great solution.

Here, I deliberately suggested placing the (first) opening leaf preferably in the “corner” in order not to sacrifice the dining table space in an already less than clever floor plan. My actual favorite here would have been a two-leaf outward-opening door flanked by two narrow fixed panes just around the corner.

It would be nice if the OP not only liked my contribution but, even better, also answered it.

In the “old” house we had large sliding doors and are much more satisfied with the current solution; [...] I always consider the often seen piece of furniture (sofa/bed/desk...) in front of floor-to-ceiling windows to be a planning mistake, as well as the floor-to-ceiling windows here in the bathroom; for me, these are rather trendy, therefore ephemeral and less sensible ideas.

(Where) have you ever shown your house?
In my estimation, lift-and-slide doors will take first place as the “Retro Building Detail 2027,” but they kept their supposed must-have status for about 50 years. What went away surprisingly fast, though, were the scarlet accent surfaces on the Anstattvillen (as predecessors of the Smokey Eyes).

Since construction apparently has not yet begun, the question arises for me whether you want to post your building project here (including discussion about the floor plan) to perhaps come to further thoughts about which you might regret after construction.
Often people don’t want to because they feel it’s “uffff... finally done,” but a subsequent awakening can be permanently annoying.

I can only agree with that.

As a reference: We built with a developer (who then subcontracted a general contractor) and for us the lift-and-slide door in 3.6m width and an increase from 2.2 to 2.5m height cost ~€4,000 net surcharge. Plastic-aluminum windows from Internorm triple glazed. Since we built with a developer, we had no opportunity to assign the matter otherwise.

But it was worth it:

I suspect I have found the reason for the hefty additional payment. The contract does not even include the windows drawn in the floor plan, but only the calculated minimum that is legally required.

I suspect I have found the reason for the hefty additional payment.

As stated, the volume roughly corresponds to the total price of the entire house window installation ...

The contract does not even include the windows drawn in the floor plan, but only the calculated minimum that is legally required.

... so the standard-required windows would at least have to be offset.