A heat pump is a machine or device that transfers thermal energy from one location, called the "source," which is at a lower temperature, to another location called the "sink" or "heat sink", which is at a higher temperature. Thus, heat pumps move thermal energy opposite to the direction that it normally flows. While compressor-driven air conditioners and freezers are examples of heat pumps, the term "heat pump" usually implies devices not dedicated to refrigeration.
HEIL heat pumps have two-stage scroll compressors that operate most of the time at the quieter, lower stage, changing over to the higher stage at higher outdoor temperatures to produce more cool air. A deluxe sound blanket also reduces compressor sound levels. The painted, galvanized steel cabinet features a powder-coat, baked-on finish and a coated inlet grille with narrower spacing to provide maximum protection as it allows for proper airflow and easy coil cleaning. The scroll compressor and the copper 7 mm tubing with aluminum fin coils work collectively to save on energy. The two-speed fan motor operates most of the time on the quieter, lower speed. Aerodynamic air discharge design reduces operating sounds. Matching with the variable speed indoor fan allows whisper quiet indoor operation