Both are ceiling mounted systems, but fundamentally a bulkhead system is designed to provide air conditioning to a single room whereas a ducted system provides air conditioning to multiple rooms throughout a home or business. A Daikin ducted system (such as the Premium Inverter, Standard Inverter and Slim-line series) is designed to provide flexible duct-distributed air conditioning in multiple rooms, with the indoor unit being installed in a ceiling space. In comparison, a Daikin bulkhead system (such as the Inverter Bulkhead) is designed for single room air conditioning with a minimal duct run and is best suited for installation in drop ceilings.