Renovate house from 1988 - windows and front door?

For the windows, I would recommend triple glazing with warm edge spacers, don’t skimp on the profile in the patio door area, generally better to go with 85 mm depth or even aluminum patio doors. Not anthracite, but stick with white or light gray. Everyone has anthracite.

Looking at the pictures in your 2nd post, you can keep the profiles if they are stable and not flimsy. Then you can just change the glazing and have no chiseling work. You can leave out the muntins. I don’t find internal muntins attractive either, but having none at all is also dull. I prefer real muntins or multi-wing versions – but that requires a complete replacement.

In general, fixed-glazed sections are significantly cheaper (not a fixed sash, but simply fixed without a sash). You can also achieve great effects with window layout, for example, for wider windows you can have a relatively large sash in the middle and narrow fixed glazing on the left and right. It’s cheap, you get a visual elongation in height, and you also get spots on the windowsill where you don’t have to clear things away when ventilating.

From the pictures, the reserve of the glazing beads is not clearly visible, perhaps only double-glazed units will fit again,

The roller shutter boxes immediately catch my eye: Are they properly insulated and sealed already, or does it possibly draft through there? No idea what was done in buildings from that year.

what do you mean by reserve of the glazing bead.

By Prof m profile and 85 you mean the depth?

You can see how much reserve the sash profile has on the glazing beads. The glazing beads themselves have no reserve; you replace them when you install a thicker glazing unit.

I referred to the triple glazing regarding new windows including the frame. With the existing ones, that will probably not be possible. But even so, the questioner here will achieve a reduction from the current U-value of 2.5-3.0 to about 1.0-1.2 with new double glazing with a warm edge, which results in approximately 100-150 kWh / m² window area per year in heating demand reduction. What is not improved then are weak points in thermal insulation on old window profiles as well as possibly ventilation losses due to old or defective seals.