Hitemp is an app which enables smart remote control of heat pump water heaters. It uses email and verification code for registration. In this case, the units will be bound to the app by scanning the bar code on the units. Then users are able to control the units through networks, including startup & shutdown, temperature setting, mode switching and so on. Meanwhile, it can record the operation status of the units constantly, and alarm in time when certain faults happen to the units.