Hi, what a great forum! I am about to install a Century 2500 insert into my existing brick fireplace, but the building code/permit people of Ottawa have said that I need to supply "a 4" combustible air supply" which is going to be a problem as there is no knockout or allowance on the back or sides of my unit up to which I could connect an air inlet. If I were to "drill a 4" hole" in the back of my existing fireplace to let in air, it still would not reach the intake air vents of the stove which are on the room-side sides of the unit, due to the facing plate around the stove. Any suggestions would be VERY welcome; I'm wondering if any of you have had to solve the same problem with your inserts, or do most inserts work well using the room/house air. Not sure if the inspector would accept that I would open a nearby window a crack every time I have a fire. Thanks in advance for your advice.