Thermal envelope and partial basement: How to insulate, experiences?

Hello dear house builders,
in existing houses (especially from the 70s / 80s), some rooms in the basement are often designated as living space and are correspondingly developed, e.g. with generous light wells in front of the windows, ceiling height, etc.
How do you bring a partially habitable basement up to a contemporary insulation standard? Basically, the basement living rooms would have to be included in the thermal envelope of the living space. However, these would then have to be insulated against the other basement rooms. In the utility basement rooms, on the other hand, the ceiling to the ground floor would then have to be insulated.
I find very little information on this topic on the internet, which really affects many existing houses. What is the general insulation concept for partially habitable basements?

How do you bring a partially residential basement to a modern insulation standard? Basically, the basement living spaces should be included in the thermal envelope of the living area. However, these would then have to be insulated against the other basement rooms. In the utility basement rooms, on the other hand, the ceiling to the ground floor would have to be insulated. I find very little information about this topic on the internet, which really affects many existing houses.

... but it probably leaves many experts puzzled as well. In principle, you are thinking correctly, but one problem is that the boundaries between residential and utility basement rooms are not identical to those of the ceiling panels, so ceiling panels often span these boundaries. Theoretically—although the reduction of the clear height argues against it—the residential basement rooms should also be included in this ceiling insulation to the ground floor, in order to mitigate the impracticality of implementing the theory.

… just the missing basement floor insulation alone is a problem, right? It's best not to shake the topic. Focus on the essentials, namely the living levels, that is important. …and if one or the other room in the basement invites you to stay, you don't need a usage application for that :cool:

Alternatively, insulate the entire basement. It is certainly more pleasant than living in a damp, cold utility basement. Basement floor insulation a problem? Are all houses