So, we have a ceiling height of 2.65m on the ground floor and the living room is about 40m². I find that very suitable. Recently, we visited a neighbor who just built a new house. He only has 2.45m height and a similarly sized living room. The lower height immediately stood out to me and felt a bit oppressive. But the room was still empty – with furniture it might feel different again.
In smaller rooms, 2.45m is completely sufficient, in my opinion. From 40m² onwards, I would go a bit higher. Therefore, we have 2.65m on the ground floor and 2.45m on the upper floor, as there are only small rooms here.