Why should everyone sell their old houses? But old houses have the advantage that you can also heat some rooms less because open floor plans are rare. My grandparents only heated the bathroom, living room, and dining room in winter with stoves and an electric heater. The kitchen was at most tempered. The remaining rooms were not heated. Doors were closed and people dressed warmer. And the windows had single glazing. Every autumn the storm windows were installed to have double glazing. And people dressed warmer. And this is still the case in many old houses in the USA, GB, and Europe today.
You can certainly try that in a newer house – mold says hello. My grandparents heated their farmhouse just as you described and ultimately had a huge mold problem behind all the cabinets. Whether that was the trigger for my grandmother’s respiratory problems I do not want to judge.
I am not telling anyone to sell their house. I just assume that many first owners of such houses simply will no longer be alive in the coming years. In my father’s neighborhood, at 79 years old he is the youngest. The street has become a real old people’s ghetto, but the residential population will probably be completely replaced within the next ten years.
However, I recommend that people sell their old house if they simply can no longer afford the maintenance. This includes not only ongoing renovations that serve to preserve the substance but also maintenance costs such as electricity and heating. Why should I only heat two rooms in a 200 m2 house and ignore the rest when I can temper all rooms as I want for less money per month in a 3-room apartment?
Example: My father needs on average 3,000 liters of heating oil for his house and complains louder each year about the heating costs. Our neighbor across the street is the same age and pays 40 euros per month for heating his apartment. I have never heard him complain...