Dual condenser heat pumps are essentially an "O" (water-to-air) and "W" (water-to-water) series combination heat pump. The addition of a second, full-condensing, refrigerant-to-water heat exchanger allows the "DC" unit to function as a water-to-water heat pump whenever the unit is not calling for "air" heating or cooling. Switching of modes is done electronically with the air side of the system having priority. The priority of the "DC" unit can be reversed at the time of factory order so that hot water output has priority - with off cycle time available for hot or cool air production.