What is your heating system?
Everything is focused on the feeling of radiant heat on the skin. Bringing the "sun feeling" into the house even in winter is very important for our health. Price and payback time are subordinate to this aspect. Minimal running costs over the year on balance—if anything has to be paid at all—this is reassuring in case things get "tight" in old age. Aesthetic preferences do not help save on acquisition costs.
Our house section: Ortner Grundofen according to our own design as the main system (sustainably sourced wood from our own forest behind the house) and infrared as a supporting system. Vaillant hot water heat pump with storage tank. Apartments for the boys (2 identical): Hase wood stove as a cozy heat source, infrared designed as the main system, hot water via instantaneous water heater. 9.99 kWp photovoltaic system with Autarq solar tiles with Kostal hybrid inverter and 12 kWh high-voltage BYD battery, also connected to the hot water storage. Covered terrace area: infrared heating lamps for the transition period. Clay plaster helps with moisture regulation and serves as a heat storage.
When the boys (17 and 19) have moved out, the apartments will probably only be used sporadically and not fully heated in winter. Intended as a ground-level bedroom in old age with space for physically restricted living.