Answer:
The farm cottage typically had a single big room. In the middle of the floor there would be a hearth, possibly made of stone, on the floor. Above the hearth was a hole in the roof for the smoke to go out. What are called smoke canopies or hanging chimneys might have been used. They were simple, light guides to carry the smoke to a hole in the roof or wall.
The windows were usually unglazed, and so the houses were drafty. It was rather like camping out in the winter, and so the most important way to stay warm was to wear a lot of thick clothes.
The modern chimney was not invented until the 11th or 12th century, and then was too expensive for farmers.
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