Window variants: Stulp vs. mullion

What is supposed to be good/bad? Stulp/mullion now has no influence on your concerns.

I would do without Stulp: what is that supposed to be good for?
You install a Stulp window when you have a patio door and the mullion is annoying.

The practical consideration of cleaning the fixed glazing cannot be denied.

Still, just as a thought: we have so many and unusually sized windows that we have to have a company come to clean them. It’s not that expensive if you don’t do it monthly. I wouldn’t have thought to design the beautiful house according to the cleaning possibilities of the windows.

BTT: Take the regular windows with a central mullion. They are, afaik, somewhat more common in manufacturing and therefore possibly slightly cheaper, a bit more stable in the frame construction, and – as mentioned above – the sashes can be tilted independently of each other.

Regards

It is about the windows in the children's rooms. These are the 2nd windows, meaning there is still a floor-to-ceiling window on the gable side.
The windows in question (with roller blinds) are located on the eaves side (south side) in the knee wall (finished interior height 1.80m) and are currently planned to measure 2 m x 70 cm (height 72cm) (it is known that fall protection is required). [...]
In the meantime, however, we are no longer sure whether 2 meters is not too wide after all; we are now leaning towards a width of 1.76 m.

I wouldn’t think of a double casement but only tilt. You then hang it out on the hinge for cleaning; it disturbs less above a desk than if you have to clear it for opening. For a secondary window, tilt-only should be completely sufficient. This way, even fall protection might be dispensable (but I’m not exactly familiar with the standards). Regarding the window widths, I tend not to "mix" dozens of different formats and lintel widths in one house. In this respect, I would also take a look at what other window formats are used in this house.

I don't think of double-leaf at all, but rather tilt-only. You then detach it from the hinge for cleaning; it is less obtrusive above a desk than if you have to clear the desk to open it. For a secondary window, tilt-only should be completely sufficient. This could even make fall protection unnecessary (but I'm not exactly familiar with the regulations). Regarding window widths, I tend not to "mix" numerous different lintel widths on one house.

You have to weigh that carefully: although you don't need fall protection, cleaning can only be done by two people! We have a 70 x 150, and it is very heavy when detached.

We had windows with a mullion in the apartment and have now consciously decided on [Stulp] (to no longer have the annoying mullion). I would not want special solutions (only tilt?), I would take completely normal windows. Just with or without [Stulp].

We have a 70 x 150, and it is really heavy in the open state

I meant: leave the bottom normally hung and unhook the scissor at the top to switch from tilt opening to full opening.

We had windows with a central mullion in the apartment [...]
I wouldn't want special solutions (tilt only?), I would take completely normal windows. Either with or without a mullion.

A mullion or a central mullion is practically an optical difference of a few centimeters of frame width in the middle. Landscape format looks more deliberately consistent to me if you don't divide it in width. Tilt-only is not a special solution: it is the same window with a somewhat cheaper opening mechanism, nothing more. Only unlike the fixed element, it is suitable for exterior cleaning without scaffolding.

"Normal" tilt-turn costs (a bit) more, while I wouldn't take pure turn; at the intended height it "sweeps" a table in front of it.