The Sirac heat pump absorbs free energy (heat) from the air and upgrades it to a higher temperature, via the refrigerant cycle.

A heat pump is essentially a vapour compression cycle being used for air-cooling purposes with the associated heat as a by-product; a heat pump utilizes the heat generated in the cycle to heat water.

Heat pump efficiencies are as high as 4:1 i.e. for each 1kW of electricity consumed; approximately 4kW of heat energy is produced

By contrast, conventional electric geysers produce 1kW of heat for every 1kW consumed.