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?
sounds good just make sure the extra air is available if not you might not have enough static pressure to push the air up stairs and floor are slightly better for heat but if you use the ceiling go with square deffusers and have the return close to the floor high supply low return or visa versa