ᐅ Interior insulation of a non-insulated wall = risk of mold growth

Good day dear experts,

we are not planning to build a house, but we hope someone might still be able to help us with a "building question."

We are considering renting a ground-floor apartment in an old farmhouse. All rooms are insulated from the inside, except for the living room (one wall) which is not insulated.
Now we are worried that water might accumulate on that cold wall and cause mold to develop.

Is our concern justified, or are we overreacting?

You actually addressed experts, and I’m not one either, but from a purely physical standpoint, it is possible that moisture from the indoor air condenses at the coldest spots. However, this depends on many factors we cannot assess here, not even as experts. One thing is fairly certain: if there is a moisture problem, it will likely appear first in the corners by the cold wall, where there may then be a risk of mold.

For example, how high is the humidity level? It would generally be worse in the bathroom or kitchen. I have also seen mold in bedrooms, where less heating is used and people release moisture into the air during the night. Cold air can hold less moisture, so condensation occurs more easily.

How much moisture is introduced into the room by occupants, aquariums, plants, etc.?
How well is the room ventilated? Can moisture actually be removed outside this way, or could continuous ventilation under certain conditions bring in additional moisture or cold air?
How much is the room heated? What is the temperature difference between the uninsulated walls and the insulated ones?
What material is the wall surface made of? At least the mold risk also depends on this.

These are all questions to consider if you want to provide a definite answer. If in doubt, simply ask the previous tenants about their experience or hire a professional to inspect the premises.

That depends on many factors. However, it is much more likely that mold is growing behind the insulation.