Good point, and true even if people were to open windows to fresh air (open 2 on opposite ends of the house). Entirely possible I have a source by default...I

Good point, and true even if people were to open windows to fresh air (open 2 on opposite ends of the house). Entirely possible I have a source by default...I do have a chimney and even with the flute closed I feel a draft. All I know is in the past, before replacing my hood I can smell the cooking from upstairs...now I can't.