Siddons Solarstream heat pumps "capture" and thermally magnify the ambient temperature of the air to create hot water. They typically use only about 1/4 of the electrical energy of a conventional resistive element hot water service. Heat pumps are an excellent choice where direct solar radiation is poor and no reticulated gas service is available. They attract very substantial rebates from Sustainability Victoria (up to $1800) plus REC's of around $1,400.

A heat pump is a form of solar water heating that does not rely on direct sunlight. Instead, heat is extracted from the atmosphere using a refrigerant gas and compressor, commonly known as a heat pump. The refrigerant liquid passes through a collector absorbing heat from the atmosphere and evaporating the refrigerant to a gas in the process. The heated refrigerant gas then moves along a coil wrapped around the storage tank where it condenses into a liquid and heats the water in the storage tank. The electricity consumption is similar to a solar water heater with electric boosting consequently they are treated as electric boosted solar systems. Running costs can vary as heat pumps may need to be connected to a continuous electricity supply.