A control system includes an electric heater disposed within an exhaust fluid flow pathway, and a control device for receiving at least one input selected from the group consisting of temperature readings along the exhaust fluid flow pathway, alternator power/current/voltage, battery power/current/voltage/state of charge, IAT and EAT profiles, mass flow rate of an exhaust fluid flow, NH3 slip, TCR characteristics of the heater, alternator speed, engine speed, state of aging of an aftertreatment component, state of aging of engine, aging degradation characteristics, a dosing rate and a temperature of DEF, NH3 storage condition of aftertreatment system, an ambient temperature, and combinations thereof. The control device modulates power to the heater based on the at least one input such that the heater provides different power output as a function of the at least one input and a continuously variable power output during operation of the exhaust system.