Feature: 1) economical operation Generally cost less to operate than other types of conventional heating systems, save your electricity or gas bills. 2) safety Operate at a high efficiency with no flames, fumes, or flues; water and electricity isolated 3) environmental friendly Transfer heat that already in the environment; low co2 emissions. 4) easy operation With intelligent control systems which convenient and simple operation 5) constant hot water supply Provide hot water no matter in cloudy day, snowy day or at night, unlike solar collectors which have to be facing the sun. 6) wide application Heat pump water heater can be applied to sanitary hot water, house heating and so on.