1) Air source energy 2) Higher efficient than gas,electric 3) Minimum noise 4) heating capacity:72000-306900BTU/H Air source heat pump,air to water heating pump.Be wonderful for your private swimming poolsExtend the swimming seasonWorking principleTransfer heat from the outside air to the pool.Providing the most energy efficient pool and spa heating available.Advantages:1. Compared to gas,oil or ...