[esskay]

Does very much depend on your location. In the UK a dehumidifier is still often a good idea in the winter because although our humidity drops, its nowhere near enough. Inside can still be high 50's, in older properties it'll never really go below 60%.

Really a lot of our older homes shoud be retrofitted with a MVHR unit to help things as ventelation is awful in most houses. I'm actually quite surprised a lot of landlords in the UK don't do it as theres always a fight between them and their tenants who don't necesserily want to leave a window open all day in the winter to stop mold.

[ZeroGravitas]

Positive Input Ventilation (PIV) units seem to be a new thing for landlords to battle this problem.

I think it basically trickles in cold (and therefore drier) air into a central space to reduce humidity, like an (slower, quieter) extractor fan in reverse.

Seems a bit of a conflict of interest still, especially if the tenant is paying for heating.