The market for variable refrigerant flow (VRF) is expanding from the points of view of efficiency and less installation work. There are also some strong needs for the existing water-based air conditioning systems. Low GWP systems, which uses flammable refrigerant, typified by R32 refrigerant, have been developed to stop global warming, so it is necessary to take measures against refrigerant leakage into rooms. Mitsubishi Electric has developed the world’s first water-based hybrid-VRF (HVRF), applying its heat recovery VRF technology’s merits with refrigerant to water heat exchanging, and launched as Hybrid City Multi. Since the developed technology meets the refrigerant regulations, which are expected to be strengthened in countries around the world, it will become a standard air conditioning system realizing a low GWP system with a reduced amount of refrigerant, and zero leakage of the refrigerant into the room in this field.