As winter has got cooler and the humidity in external air has dropped we have found that one room, the master bedroom, has developed a lower humidity during the day. This is less the case in other rooms but activity in those rooms may be adding the missing moisture.
The master bedroom does not feel dry to us with a humidity of 30% or less. In fact during overnight occupancy you can see the humidity rising from 27% to 31% and then falling again during the day. The room has an MVHR inlet valve.
The MVHR humidity readings at the time of the above are
So external air is being supplied at a humidity of 24% and the average house humidity at extraction is 37%. No cooking, showers or baths are in progress. There are clothes drying but they are now adding very little humidity, having been washed overnight and been drying all day.
If the humidity, or lack of it, in your home is causing dry skin then an active humidifier may be needed. Mrs G and the children all use moisturisers but then African skin tends to be dry. If the dryness is irritating the airways it should be addressed urgently.