Abstract: A combined chiller-boiler HVAC system which integrates all operating components including the boiler, chiller, distribution pumps, condenser coils, condenser fans and controls onto one single enclosed platform built for installation exterior to the structure being served and designed to produce heated or cooling fluid sequentially or simultaneously in differing areas of a building on demand. This system utilizes both air and water cooling whereby waste heat absorbed during a water cooling cycle, can be captured and re-directed for other uses.