BLIMP said:any exterior chimney is a poor drafter & the house itself has a chimney effect but if u can crack a window near the fireplace & it works then...
if u had a neg. pressure prob i'd guess your cellar fireplace would stink during the summer when vents are running & windows aint open?
FYI= old wisdom sez NEVER TRY TO HEAT A HOUSE FROM THE S SIDE , this is because the prevalent N winds of winter result in N-S airflow in a house.
u have complicated scenario though interesting
the fireplace never stinks during the summer unless i run the whole house fan with out enough windows open
my house pretty much faces north.. the large over hang was to allow for thermal heating in the winter and cooling in the summer .. my stove (summit) are all in the house facing east .. same as my fireplace in the basement.. the pellet stove is on the east side of the house pointing west?
so do you think cracking the windows will solve it? and how will that effect the temp of the house.. in the winter
dont know if it matters but my chimney is interior not exterior.. could that be adding to the problem?