Divide room later

Hello everyone,

we are planning to create three bedrooms upstairs from two large bedrooms (27&23m2). In the larger room there is a double-wing window in the middle. In the smaller room there are three door-sized floor-to-ceiling windows in the middle. How much effort is it to divide one of the rooms with the existing windows? What is the best way to do it (drywall partition?). Is a narrow piece of wall between the windows enough to install a plasterboard wall here? And how do you solve the heating problem, since only one room retains the radiator?

Thank you very much in advance.

Hello Nico,
have you already clarified whether the wall, which you obviously want to remove, is structurally relevant?

No wall is to be removed, only an additional one added.

So, one of the two rooms is to be divided. Which room will depend on effort and windows?
Perhaps a drawing of the existing condition would be useful?

Best regards in brief

Maybe a drawing of the inventory would be useful?

... and photos.

We plan to turn two large bedrooms (27 & 23m2) into three on the upper floor. In the larger room there is a double casement window in the middle. In the smaller room there are three floor-to-ceiling windows, door-sized, in the middle.

I’ll interpret again :-) that the "double casement window" means a connected window element with two sashes and a mullion in between, which can be opened separately (so not a French casement), but presumably only one of them is tilt-turn instead of both; and that between the three floor-to-ceiling windows there are each covered beams? – or does "a narrow strut" mean it is a connected element with three posts in window frame profile width?

And how do you solve the heating problem, since only one room keeps the radiator?

The simplest solution would probably be to make a branch for another radiator from the existing radiator (insert a T-piece, then it can be extended to the new radiator via hose). In terms of control, the second one can practically be a slave, so with the same room size it would be conveniently the same size as well. But the heating engineer has a more solid opinion on that than I do.

Correct, all the assumptions were right, the double-wing window as an element with two windows to be opened and a narrow mullion in between. This is about 2 cm wide when the windows are closed, where a wall could be docked. The floor-to-ceiling windows have wider mullions and are about 8 cm wide when everything is closed.
Attached is a floor plan. I cannot take photos at the moment.
WITH the heating that sounds good so far.