One oven was in her bedroom and one in the small living room. It would take about half an hour to warm up the rooms and the heat was constant and pleasant as long as you added a coal every now and then. However, she loved to air the rooms early in the morning and would open up the windows while we would cover ourselves with more blankets.
In the kitchen there was no heating at all, just a very small warm water boiler tank above her small sink, that she filled up. It held about 5 liters, and you pushed the heating button and the water would heat up in a few minutes.
Picture from the web of a more recent model:
Although I had visited Berlin many times before with my parents and knew the ins and outs a bit, I was not at all prepared for all the hurdles we would have to take. I switched into vacation mode in my mind and hoped that this was all temporary and we could return home soon. I was so wrong....