I am finishing up my install on a used Harman Accentra insert. I have been told by some that I should run a pipe from the air intake (which is located behind the stove in the back of the fireplace) through the back of the fireplace to get outside air. Some folks have said you don't have to do anything and it will draw air from the chimney and you'll be fine. The chimney is obviously capped at the top. Certainly not air tight but I would like some thoughts on this from the forum. This is my last serious concern other than pellet choice. I think I may go with Hamers Hot One's and leave it at that. Thanks for your thoughts on this.