Most homes use a single primary form of heating, and are tied to whatever costs or inefficiencies those may incur – gas price spikes in a gas furnace, for example, or reduced efficiency in heat pump systems when outdoor temperatures are low.
A dual-fuel system combines the best attributes of combustion furnaces with an air-source heat pump and helps you save energy throughout the heating season. In the winter, a heat pump extracts heat from the outside air and transfers it inside for efficient heating – that is, until temperatures fall to around 30 degrees. At that point, with a dual-fuel system, a high-efficiency furnace takes over the work for comfortable, relatively affordable heating. This is preferable to the emergency heat in a regular air-source heat pump, which will trigger an electric heating element that's expensive to use.