Almost ALL Home Convection Units are vented to the inside of the Kitchen. Very few Homes have a Mount for the Convection oven on an exterior wall to vent outside. When the Convection ovens are unpacked(99% are regular HOME Ovens), the exhaust fan is mounted to vent inside. On an RV, it is up to the OEM to determine if they want to cut the exterior hole for venting outside. When that is done, the Fan system is removed and reclocked to blow out the back of the Convection oven. The Oven Fans are designed to be rotated to blow inside or outside. Doug