The Toshiba Estia Air to Water heat pump's design is inspired by variations of Toshiba's outdoor units, the Super Digital Inverter. It features heating controls for two zones and produces hot water that is sanitary. It comes standard with a back up electric heater built in. It has a supply of one phase and is an outdoor unit. The single hydro module has three phases to choose from. It features a double rotary inverter compressor that is highly productive. Its compact design makes installation easy in any location. It has a back up boiler which boasts an optional interlock. It comes standard with a user friendly controller. These systems can offer cooling or heating water in two separate locations on the machine. It also offers hot water when you add a tank made from stainless steel.