The integral DHW tank of the compact hot water heat pump has a capacity of 300 litres and delivers a usable volume of water of up to 375 litres for households of up to 5 people. A coil can be used to also connect a solar thermal system or boiler. Integration into building management systems or smart home systems is carried out via Modbus. Self-generated PV electricity can be utilised on an infinitely variable basis and to optimum effect. The fully wired appliance is quick to install and has a footprint of less than half a square metre.