Underfloor heating vs. room height, what should one do?

Hello,
I'm starting a new topic here because this is so important to us that the purchase decision depends on it.
I have already opened two threads about the property:



Today I received the cost estimate. Although we indicated underfloor heating as a preference, the engineer planned with radiators. My inquiry resulted in the following: Currently, there is a floor structure/screed with a height of 6 cm. (You would completely remove that for underfloor heating, right?) According to him, underfloor heating requires 10 cm, and if we want a central controlled residential ventilation system, it even needs 15 cm. We don't need impact sound insulation on the ground floor, as there is only the basement underneath.
The construction plan states a height from the finished floor level of 2.65 m. Plus the removed screed, that would be 2.71 m. Subtract 15 cm for underfloor heating and controlled residential ventilation and another something for the floor (we want tiles), I generously estimate (?) 2 cm. That gives me 2.54 m. That is still okay as a room height, right? We currently have 2.56 m plus a few millimeters. Can you notice a 2 cm difference?
Is my calculation correct, or will there be more centimeters added?
The stair step height would have to be changed somehow and the door openings raised, but that is worth it to us (up to a certain amount).
Of course, I will ask the engineer again, but I would appreciate your opinions/advice!
Thanks :)

The exterior door and terrace door would also need to be adjusted. All the windows then feel about 10cm too low. Does the structural engineering still support the whole thing?

Does the static structure still support the whole thing?

Good point, I will ask as well. I hope I will get a statement on this and not just be referred to a structural engineer... At my first inquiry, the static structure was at least not mentioned.

The windows then feel about 10cm too low

Are there standard heights for windowsills? In the kitchen, I would like them anyway to be lower so that they merge with the countertop :) Nowadays, door heights are quite a bit higher than 2m, at least in our new build house, so I actually think making doors taller is not wrong at all.

In terms of pure ceiling height, I don't think I would have any concerns. For us, we would have started at about ~2.57m and then got accordingly lower (and therefore decided against it).

Heutzutage sind die Türhöhen ja ein ganzes Stück höher als 2m, zumindest bei uns im Neubauhaus, deshalb finde ich Türen höher machen auch gar nicht verkehrt.

The new building standard is probably 212.5cm, while old buildings often have about ~200cm. Changing interior doors is probably not such a big effort (relatively), since the width of the lintel is manageable.

I am just looking at the old construction plans and have just discovered that there are 2 different cross-sections, one with 2.65m and one with 2.50m... but the plan with 2.65m is stamped by the building authority, so it was probably built that way? We measured the ceiling height in the house, unfortunately I don't remember the value anymore :( but I would definitely have remembered anything under 2.50m.

Changing interior doors is probably not such a big effort (relatively), since the width of the lintel is manageable.

It always looks easy on [Zuhause im Glück] ;)