Window with roller shutter box versus window without replacement

I have an existing property with older windows and built-in roller shutters.

Now I would like to install new windows and we have considered taking out the windows and roller shutter boxes and replacing them with correspondingly larger ones. That should bring a higher energy effect, or am I mistaken.

At some point, top-mounted roller shutters are to be installed.

Thanks and regards

That should bring a higher energy effect, or am I making a mistake in thinking.

I don't know, explain that in more detail, where the effect is supposed to come from.

At some point, external roller shutters are supposed to be installed.

Which, firstly, protrude outwards and secondly would already have to be planned at the window (?).

I was a window factory manager and cannot follow your logic.

Don't know, explain that in more detail, where the effect is supposed to come from.

Does he maybe have old, undamped roller shutter boxes now?
Then current double glazing would probably be an energy gain.

But I also don't understand why you would want add-on roller shutters later. Now would be the right time to avoid this optical compromise.

First of all, thanks for the answers and food for thought,
my consideration was simply to remove the old roller shutter box and "fill" the resulting opening with a correspondingly large window.
I assume that an installed window is more airtight than an old window with a roller shutter box.
What I did not consider is that a subsequently mounted higher roller shutter would then have to be installed over the already higher window.

For me, the cost issue and the distribution of costs over time play the decisive role here. Therefore, tight before dark.