A modular heater system is provided that includes a heat trace assembly and a connector assembly. The heat trace assembly has a heat trace section that defines a plurality of fins, an insulation jacket surrounding the heat trace section, and at least one terminating member disposed at an end of the heat trace section. The connector assembly has a shell, including a plurality of outer walls and inner walls defining cavities therebetween, and a fitting heater assembly that includes a fitting adapter, a heat trace section disposed around the fitting adapter, and an outer casing disposed around the fitting adapter.