So if you have completely shut off the shut-off valve at the HKV, the heat probably comes passively from other parties or through solar gains. How warm is it with you? Year of construction?
I don't have a thermostat in the apartment. But I would estimate it to be around 24/25 degrees at times. Year of construction 2004 if I remember correctly.
I am on the ground floor, so the heat should not be coming from other units.
You don't have temperature control in the apartment? I didn't even know that something like that is allowed in Germany. And you also don't have a thermometer or why do you have to estimate the temperature?