An air-to-water heat pump absorbs heat from the surrounding air and transfers it into the water line. Heat pumps transfer heat by circulating refrigerants through a cycle of evaporation and condensation – basically the reversed process of a household refrigerator where the heat energy produced is used for water heating and the by-product is cold air. This system yields a relatively high Coefficient of Performance (COP) in ASEAN countries having a minimum of 25°C ambient temperature, requiring less amount of electricity to generate heat for hot water use.