This plant (installed in a 200 m² two-floor house in Pordenone - Italy) is made up of a well water condensed heat pump with variable flow “digital” scroll compressor and of ceiling radiant panels. The heat pump supplies also the tap water storage tank. A mechanical ventilation plant with an active energy recovery from exhaust air provides the indoor air quality. The system mounts new high efficiency electronic filters. The CPU of the system programs and controls the entire system. A simplified physical model of the plant was built to calculate its annual efficiency, the energy consumption of each component and its life cycle costs.