I'm sure it gets fuzzy on the edges, but "I don't heat and it's still warm" isn't in that zone. What I'm talking about is: given you want ~18°c/60°f in rooms o

I'm sure it gets fuzzy on the edges, but "I don't heat and it's still warm" isn't in that zone. What I'm talking about is: given you want ~18°c/60°f in rooms on average (20°c/68°f for more comfort), and you have a fixed volume of space inside a building, you're not magically saving energy by turning your heat down, because your neighbors need to turn theirs up to achieve the average temperature because insulation is mostly on the outside, not between flats. You could counteract that by insulating your rooms towards your neighbors, which would also achieve your goal of not going above 10°c/50°f.