In a heat pump system, what is the role of auxiliary heat?

In a heat pump system, auxiliary heat serves a crucial role during periods when the demand for heating exceeds the capacity of the heat pump. This typically occurs in colder weather when the heat pump struggles to extract sufficient heat from the outside air. Auxiliary heat provides backup heating to ensure that the indoor space maintains a comfortable temperature. It acts as a supplement to the heat pump's primary heating function, particularly during defrost cycles when the heat pump must temporarily transition to prevent ice buildup on the outdoor coil.

The primary reason for utilizing auxiliary heat is to maintain consistent indoor comfort levels when the heat pump alone cannot meet the heating needs due to lower outdoor temperatures. This is essential for ensuring that the heating system operates effectively throughout various weather conditions.