I suggest buying a hygrometer so you don't have to guess. In most places you'll quickly find out that you can bring humidity down to acceptable levels with a fe

I suggest buying a hygrometer so you don't have to guess. In most places you'll quickly find out that you can bring humidity down to acceptable levels with a few minutes of "shock" ventilation. You can of course turn on the heating for a few minutes to bring humidity down a few percent-points more (entirely optional), but it absolutely doesn't have to be turned on all day long to have acceptable levels.