Only get condensation when heating on in winter, when it's really cold/ frosty. Get black mold on window of unused room is I forget to have window slightly open.
Recently found downstairs bathroom not insulated but now remedied, it was the worst. Other rooms about the same for humidity 58-70%...
I've been in the house for 7 years, a victorian 1901 with cavity. We installed central heating have brown spotty walls upstairs. Have injected chemicals downstairs with chemicals. Around 7 courses spalled bricks above damp course down length of house. Walls are always cold.
Humidity in house...