Jenn-Aire exhaust fan system means business. Homes with fireplaces need to be careful as the exhaust fan can pull a downdraft on the fireplace and introduce CO into the living space. The Jenn-Aire system is nice for keeping grease and smoke out of the house though. I ran a pipe down through the floor in my home in MT, and then ran the vent out side between the floor joists. The chief cook likes her Jenn-Aire so I found the work required to vent it was well worth it.