Have noticed a slow build up of black mould in grouting in bathroom - clearly need to up ventilation. Currently we have a timer-controlled fan in the light housing which over-runs by 6 minutes.
Before I increase the over run, it would be nice to see what we're dealing with, so we know if there is additional ventilation needed. Presumably this means a humidity measurement of some description ?
A quick google shows this from Amazon:
as always TIA