Inverter low-temperature air energy heat pump water heater unit is a circulating heating type heat pump unit. The unit is connected with the holding tank through the water pipeline and water pump, so that the water is circulated and heated in the system to gradually achieve the production of hot water and stored in the holding tank for use in various different needs. The product is designed for low-temperature environment, -35 ℃ low-temperature environment, strong heating, the highest water temperature can reach 60 ℃, to meet the hot water needs of hotels, schools, factories and other places of life.