Supplementary Heating in AirLoopHVAC:UnitaryHeatPump:AirToAir

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When using autosizing for the supplemental heating coil in the AirLoopHVAC:UnitaryHeatPump:AirToAir

object, does EnergyPlus size the coil based only on the unmet heating load remaining after the heat pump’s capacity, or is it sized for the full design heating load?

If it is sized only to cover the unmet portion, is there a way to autosize the supplemental coil to the full design load instead?

My goal is to model a dual-fuel system, where the supplemental heating coil operates on gas, while varying the heat pump capacity for cost optimization.