>cold in winter >in my region terribly humid

You need to actually reduce draft a bit (often old houses like mine tend to accumulate flaws that the elderly living there before didn't fix anymore.) and use a heating sources that matches.

Having a fireplace is fine. It could overheat the house whilst also keeping air dryer and it's essentially renewable (compared to the alternatives and houses made of more plastic insulation than anything else) if you don't mind air quality dip in winter.

That said i can see how that's no longer an option in places that have drastically increased their population