Getting humidity under 50 per cent in a freshly built house over the winter ... turned out just impossible.
We fought hard to keep it at least under 60 per cent, as you say. If it froze outside, windows in the bedroom would be covered with water droplets in the morning.
(Actually, it froze last night, quite late in the season, and the windows were wet again.)
Yeah it's a bit counter productive - you build a house with great insulation so that there is almost no heat escaping outside. And then you have to install ventilation that literally creates vacuum in your house to suck cold dry (absolutely speaking) air in to keep the humidity in check. And then you sit in the living room wondering why is there such a draft. At least new houses are built with heat recovery to solve this
Keeping humidity low is all about making sure the air doesn't cool too much, or if it does, replacing it with drier (colder) air from outside. There is a certain amount of water in air and when it cools this water will condense. Good insulation (keeping inner temp constant) is key.
We fought hard to keep it at least under 60 per cent, as you say. If it froze outside, windows in the bedroom would be covered with water droplets in the morning.
(Actually, it froze last night, quite late in the season, and the windows were wet again.)