A:Answer Hi HerbK- On GUD27 unitized washer/dryer units, the dryer is deeper in the rear than the washer. The overhang is 4" past the back panel of the washer, which means it sticks out past the vent, electrical, and plumbing connections. The dryer can sit up against a wall without adding any extra depth to the unit. This provides space for the connections in the rear. Because of this overhang, the unit does not need knockouts to vent to the left or right side. The vent elbow can be turned left, right, or down as needed. We suggest to view the Installation Instructions for dimensions and details (See 27” NOMINAL PRODUCT DIMENSIONS page 2) : http://products.geappliances.com/MarketingObjectRetrieval/Dispatcher?RequestType=PDF&Name=31-16781-1.pdf - Keep in touch! SUE@GEA