A system and method for conditioning air within an air handling system of a building is provided. The building has a hot water source and a cold water source. The conditioning system includes at least one heating-cooling unit connected to the air handling system, a primary water storage device, at least one heat pump, and a controller. The heating-cooling unit, which includes at least one chilled beam, is operable to transfer heat into or out of air passing within the air handling system of the building. The primary water storage device is operable to store a volume of water within a predetermined temperature range. The primary water storage device is in communication with the hot water source and the cold water source. The heat pump is connected to the primary water storage device and the chilled beam. The controller is adapted to selectively drive the heat pump to transfer heat between the primary water storage device and the chilled beam. The controller is also adapted to selectively control the system to transfer heat into or out of the primary water storage device to maintain the water within the primary storage device within the predetermined temperature range.