That said, insulation is still the right answer, but it ain't cheap. OP should probably tear down that beautiful old house for something more modern.
Hotter air has more energy and thus will naturally "flow" towards cooler areas with less energy until equilibrium is reached.
In this example, the higher temperature air holds more moisture. That moisture will be carried along and dispersed towards the cooler wall, where it could condensate.
But a wall will stop condensating water when reaching a certain degree of humidity. So I’m not entirely convinced one can simply divide the amount of humidity in the air by the amount of uninsulated walls (or sqm).
The air will not have more moisture, but rather all the moisture problems will be towards/on the uninsulated wall.
> But a wall will stop condensating water when reaching a certain degree of humidity. So I’m not entirely convinced one can simply divide the amount of humidity in the air by the amount of uninsulated walls (or sqm).
Condensation will never stop on a cold wall until all the moisture in the air is removed. If you boil a pot of water the air will fill with moisture, and the entire house will have a high humidity. But because one particular wall is cold because of a lack of insulation the condensation (water going from vapour to liquid phase) will be concentrated on that particular wall.
The condensation will continue to occur as long as you continue to add moisture to the air via cooking and bathing (hot showers, baths).
