Low Relative Humidity, a Problem or Not in Swedish Dwellings?

The current research investigates the relative humidity conditions in Swedish dwellings (678 apartments and single-family houses), comparing measurements from the 2007/2008 BETSI-survey (heating season), with the recommendations of the EN 16798:2019. Analysis shows that 61.4% of the apartments and 29.8% of the single-family houses belong to Cats. 3 and 4, which correspond to moderate and low level of expectation, respectively (mainly due to low relative humidity). The problem is bigger for dwellings with smaller volume, higher ventilation rate and indoor temperature, constructed mainly after 1985.