This equipment efficiently functions by transferring thermal energy (heat) from the surrounding air to the required storage that contains the water to be heated. The transfer is achieved by means of an internal heat exchanger.

These devices are energy efficient that utilize the atmosphere to source the thermal energy, which acts as the primary heat source. Hence the principle of energy saving is achieved by natural means. The system also produces cool air at the outlet during the period of operation. The system operates even during the period in the absence of solar radiation, as long as the heat source is available and in accordance to the requirements. Electric backup heating options are also available.