This paper studies an experimental performance study of room air conditioner had a rated capacity of 3.51 kW by using the reversing valve. An under split type air conditioning for heating domestic water in many private homes. The recovered energy, and the performance was replaced electricity completely for heating domestic water use because of increasing the Energy recovery. An extra charge of refrigerant in the air-conditioner could prevent its compressor from overheating during energy recovery. This experiment was conducted on varies storage tank with the capacity of the range from 22.5 liters to 120 liters. The result shows that the water temperature increased from45ºC to 55ºC. It was found that the water temperature reached 55ºC in 100 minutes from the initial water temperature of 27ºC in the 22.5 liters storage tank. In 120 liters water storage tank, the temperature increased up to 60ºC from 25ºC in 220 minutes. © 2018 Elsevier B.V., All rights reserved.