—”When we were legal residents there, our energy costs only went up and up and up”
My sister and family lived in Frankfort for many years, returning to CONUS before covid.
They have many fun stories about German electric usage/cost.
When visiting always ask before turning on an electric appliance, even a lightbulb.
Take your vacation in the coldest possible time, in order to turn your thermostat as low as it will go while gone.
Home heating systems are inspected by a government agency for efficiency. Megabucks replacement costs if lacking.
That said, they loved it there. (Brother-in-law worked for NATO)