Duct in attic
My upstairs currently has 3 rooms and 1 washroom with 1 duct for heat in the hallway and 1 for return. It never heats the rooms or washroom well enough in the winter, -30c to -40c winters. This summer i was planning to remove my woodstove chimeny that goes right up in the middle of house. I was wondering if its a smart idea to run a trunk to the attic, using the space from the chimeny, then branch off to heat the 4 rooms. Also, would installing heat registers in the ceiling be a bad idea since heat rises?