Despite the fact that most of the time it is indoor air temperature which is the main variable that defines an indoor ambience, in the present research work, indoor relative humidity was sampled and analysed in depth due to it being the more flexible variable. It is due to there not being a clear thermal insulation difference between new and old buildings, but what can be expected is a different hygroscopic wall behaviour. In each of the studied buildings, doors were half closed and the windows slightly open.