Subsequent installation of a roller shutter in ETICS

You write that it's about darkening. For that alone, you only need a good interior roller blind. Do you also want heat protection? There are even clip-on solutions for the outside. It's only about one window. A simple exterior venetian blind might also be an option. If everything absolutely has to look uniform, you will of course have to install a roller shutter and then open it up again and hope that it doesn't cause any problems afterward. Of course, that's also more expensive. But no one can make that decision for you.

The roller shutter rails are attached to the window and the box is mounted on the rails. However, for safety, I would still secure the box to the wall with construction adhesive.

but then you would need an installation space to get the box past the rails into the recess. I also find it hard to imagine that it can be mounted properly at all.

How is the operation of the roller shutter planned? Do you have power there or does a mechanical drive still need to be installed on the inside?

How is the operation of the roller shutter planned? Do you have electricity there or does a mechanical drive still need to be installed inside?

I can get electricity there with relatively little effort, that's not a problem :) I also understand that it's not ideal, but that's usually the case with retrofit solutions. What matters to me is whether it can basically be done that way or not.

Of course, it's also more expensive. But no one can make that decision for you.

Well, not really expensive. Around 200€ for the roller shutter + motor seems quite reasonable to me for a permanent solution. I can install it myself anyway. Stylish clamp variants like those from Blinos, for example, are significantly more expensive?!

But then you need an assembly space to get the box past the rails into the recess. I also find it hard to imagine that it can be installed properly at all.

What do you mean by that? The box is placed on the rails beforehand and then simply pushed into the cavity from below. Then the rails are screwed tight.

Well, not really expensive actually. Around €200 for a roller shutter + motor I find quite reasonable for a permanent solution. I can install it myself. Fancy clamping variants like those from Blinos, for example, are significantly more expensive?! How do you mean that? The box is placed on the rails beforehand and then simply pushed into the cavity from below. Then the rails are screwed tight.

€200 for roller shutter, preliminary and finishing work??