Whenever we use our wood burning fireplace we experience the entire house smelling like an ashtray for days. The smell seems to start sfter the fire is out and spreads throughout the house for days. I've tried leaving the flue open and shut and that does not seem to solve the problem. One thought that I had was that since we have a heat pump that possibly the suction from the air being returned from that room might be pulling the smell from the fireplace. Does this make any sense or do you have any suggestions?