If it has a flue or chimney, it isnt really an open fire. Look at an ancient long house, or farmer's thatched cottage from say 400 years ago. They had a fire on a stone circle on the floor in the middle of the room, and a high roof sometimes with a hole but often not. It was smoky, but kept everyone warm.

It gave people lung cancer, too. Maybe genetic adaptation to that (pretty toxic) environment is why smoking doesn't kill people more quickly.

There have been times, with various crises, where I only half considered if indoor plumbing was such a great thing. But that's probably a very old-fashioned New England thing.