How did soot get in the old houses from coal furnaces Didn't the exhaust go up the chimney?

Answer 1

Firstly, old houses were more likely to have open fires than furnaces. Lots of soot used to escape into the room and everything got gritty and dirty. Even with a furnace, some soot would fail to be drawn up the flue and would escape into the air.

Secondly, when everyone was burning coal, the air in a town was filthy, and the soot got everywhere. Outdoors especially, walls and other surfaces became coated with black, and if your washing got caught out in the rain you had to wash it again. However, it all percolated inside eventually, so everything had to be cleaned more often than it does now, and you had to redecorate more often too.