Cost of a subsequent roof window

What we had to learn from this:
- Triangular window --> Unfortunately, our triangular window can only be tilted and not fully opened.
- Heating connection: A line was laid upwards by the OG-HKV. Here we should have taken two or a larger line from the HTR.
- Ventilation system: We have no connection in the attic. So far it works quite well. This could possibly also be planned for.

But what exactly is a triangular window?

Probably what you mean by a gable window. A triangular gable window that follows the shape of the roof.

Ah okay got it. We have "normal" windows here because otherwise it was said that the roller shutters wouldn't work/would be disproportionately expensive.