Thank you for your feedback. Please allow us this opportunity to address your concerns. This range hood can be connected to a duct using any of the 3 available duct ports. Only one of the three ports (7” round port on top) is offset slightly to the side. The other two rectangular ports are centered. The slight offset of the round port is required in order to utilize a centrifugal fan configuration to maximize effective airflow. Unlike axial fans commonly used in low airflow range hoods, centrifugal fans are designed for high airflow, ducted applications where the exhausted air has to overcome the resistance generated by the ductwork.
Please note that there are no standards governing duct location. As such, duct port locations differ between range hood models and manufacturers so slight duct adjustments are not uncommon during installation. In most residential applications, ducts have the necessary flexibility to accommodate for these differences. If you require further assistance, please don’t hesitate to contact us at 1-888-449-9197. We are here to help.