This paper presents a performance analysis of the newly developed Combined Cycle Fully Integrated Air/Air Heat Pump (CFIA). The CFIA System combines the proven efficiencies of heat pump technologies with heat regenerative technologies to bring the most efficient heating/cooling system with capabilities to produce domestic hot water. The CFIA uses environmentally sound refrigerant blends. Extensive laboratory testing showed that the CFIA yielded an impressive coefficient of performance, higher than 2.7 at -15 degrees C outside temperature. Furthermore, field testing revealed an average COP of 2.4 at -13.5 degrees C outside temperature.