Line of electric circulation heaters provides heat for manufacturing and processing operations. The heaters can be used to heat thermal fluid that heats other plant equipment, or they can be used to directly heat liquid or gas products (chemicals, oil, water, air, nitrogen and steam) that flow through the heater. The heaters have high thermal efficiency to save energy. Their compact size and a small footprint require minimal space. The heating chamber of the heater houses a removable bundle of sheaved resistive elements. The material being heated comes into direct contact with the hot surfaces of the resistive elements. The elements are heated by electrical current, which can be varied to control the heat produced. Electrical current is controlled by SCRs in the heater’s control panel. The heaters are available in thermal outputs from 100 kW to about 3 MW.