Abstract: In an aspect, a heater module is provided for a heater for a thermal management system for an EV. The module includes a housing having an inlet and an outlet, a module inlet header in fluid communication with the inlet so as to receive a coolant from the inlet, a module outlet header that is in fluid communication with the outlet so as to transport the coolant to the module outlet, a plurality of module coolant conduits extending between the module inlet header and the outlet header, wherein there is a PCM storage space defined in the housing between the module coolant conduits, thermal conductors extending from the plurality of module coolant conduits into the PCM storage space, and a quantity of phase-change material in the PCM storage space and in contact with the plurality of thermal conductors. The housing is positioned in engagement with an electric heating element.