Rheem's AC and HVAC system's years of experience give you a winning combination in a dual fuel package heat-pump/gas furnace solution to your heating and air conditioning needs. In most cases, the heat pump will provide for your heating needs until such time as outside temperatures drop below a balance point at which it's no longer efficient to use the electrically supplied heat pump. At that point, the gas furnace portion of your dual fuel Rheem AC kicks in to take advantage of the cost savings that natural gas can offer you when the winter gets frigid. And Arico's detailed specs on each and every Rheem AC can explain in detail all the advantages of Rheem AC dual fuel.