What are Supplemental Heat / Electric Heat Strips?
Air-source heat pumps contain two separate heating systems: the heat pump itself, and heat strips. Heat strips are electric resistance heating coils located inside the indoor air handler, the portion of the system which circulates the indoor air. They look much like the coils inside a kitchen toaster. The heat pump itself is energy efficient and will heat the home at little expense. The heat strips operate in three different modes: De-icing – Also called defrost cycle. During winter the evaporator coil in the outdoor compressor unit becomes colder than the outside air, so water often condenses on it and freezes. To remove this ice the heat pump automatically switches for several minutes to the air conditioning mode, which raises the temperature of the frozen coil, melting the ice. During de-icing, heat strips operate to keep the system from cooling the home. Auxiliary Heat – When outdoor temperatures drop below 40 degrees, a properly-sized heat pump by itself is not able to furnish all
