... heat pump: 1.TUV efficiency certification 2.Adopts world famous parts 3.On line system 4.R410a Air Source heat pumpModel ... AW20,AW20BLow temperature air to water heat pump :AW10/L,AW13/LNormal air to water heat pump can work at above -10 ... degrees ,Low temperature air to water heat pump can work at -20 degrees.AW09,AW09B,AW12,AW12B, ... will be replied in 24 hours . Air source heat pump