This is our wonder   heat pump，high-end one.   It can work in very low temperature environments. The   Minimum operating temperature  is   -25 degress  Celsius . It adopts unique Air duct design , making it quiet operation ， which design ha ve patented .   The wonder heat pump always maintain a higher heating capacity than traditional ON/OFF pool heat pump, providing you with a quality swimming experience . It uses R 290  refrigerant, m ore efficient and energy-saving, and very environmentally friendly.   It also has a simple control system for operation.