The invention discloses an efficient energy-saving air energy water heater. The efficient energy-saving air energy water heater comprises an evaporator, a compressor, a condenser, a filter and an expansion valve which are connected in a circulating mode through a refrigerant pipeline, and further comprises a water tank, a plurality of partitions, and a condensing tube, wherein a hot water outlet tube is arranged at the upper end of the water tank; a cold water inlet tube and a refrigerant inlet are arranged at the lower end of the water tank; the upper end of the cold water inlet tube communicates with a spherical part; a first sleeve sleeves the cold water inlet tube; a second sleeve sleeves the first sleeve; the partitions are used for dividing the inner part of the water tank into a plurality of spaces, and an arc-shaped hole is formed in each partition; the condensing tube passes through the partitions from bottom to top, the part, positioned in each space, of the condensing tube communicates with a first branch tube; and the first branch tubes extend out of the water tank and communicate with a second branch tube outside the water tank. According to the water heater disclosedby the invention, the spherical part, the first sleeve and the second sleeve are equipped with a plurality of guide holes for reducing flow speed of cold water entering the water tank, so that mixingspeed of original hot water in the water tank and cold water is reduced, and a hot water utilization rate is increased.