[gambiting]

That's fine, except that the humidity in your house must be insane. I see it a lot in some British houses, where people either don't have heating on or run it very rarely - everything has this damp, musky smell of mildew. It's gross frankly. And the only way to fix it is to either run a powerful dehumidifier almost non-stop(not cheap, but at least you can keep the house cold if you want to), or....put the heating on. Opening the windows does nothing if the humidity outside is also pretty high.

[mikestew]

We keep our house at 17C/62F. I also have wood instruments, some quite expensive, for which I track humidity with a slight bit of obsession. I say “slight bit” because in the Seattle area the indoor humidity of our house rarely exceeds 50%, usually 35-45% in winter. That’s about perfect for wood instruments, and it rarely varies much, so no need to get too obsessive about it. And our house doesn’t have a mold problem.

Point is, depends on where one lives, I guess. It’s odd that you call out Britain, as that’s about the same latitude and same rainy winter weather as Seattle, but our humidity stays within a reasonable range.

[gambiting]

Well, in my British home I have one unheated(but closed, with proper double glazed windows) room - without heating, humidity is pretty much constantly at 85-90% and windows are constantly fogged up. It needs constant heating every day to stay at that usual 40-50% humidity.