What defines a "dual-fuel" heat pump system?

A "dual-fuel" heat pump system is defined by the combination of a heat pump and a fossil fuel furnace. This design is intended to maximize heating efficiency and adaptability based on varying environmental conditions. In moderate weather, the heat pump can efficiently extract warmth from the outside air, providing significant energy savings. However, during extremely cold temperatures when the efficiency of the heat pump could decline, the fossil fuel furnace takes over to ensure consistent and reliable heating.

This hybrid approach allows homeowners to benefit from the advantages of both heating systems: the economical and environmentally friendly nature of heat pumps during milder conditions, and the robust heating capacity of fossil fuel furnaces when outdoor conditions demand it.