I just installed a P23I Breckwell into my fireplace. The inspector came over and said I should have a combustion air supply to make the stove more efficient. He said I should drill a hole in the side of the fireplace or run a pipe up to the top of the chimney for the combustion air supply. In my manual it says for fireplace inserts the air supply will come from the chimney top or the ash clean out door. I'm contemplating drilling a hole in the side of the masonry and connecting some flex pipe to back of the air inlet hole to the outside. Is this really necessary? My house was built in 1963, insulated fairly well, not sure if its completely air tight?