It is already clear that the flow temperature should be as low as possible. However, since I also know apartments without thermostats, I wanted to ask, as it sounded like that. I also tried for a long time until I ended up with 30° flow @ 0° outside temperature and a corresponding slope. However, we also have about 24° in the living room and no fireplace or anything like that. The heating then usually runs, only if the window is not opened for a longer time or cooking is not done does the thermostat sometimes switch off, but I estimate the heating runs more than 80% of the time, so not too hot, I would say...