Abstract: A dialysis fluid heating system includes a plurality of conductive tubes; first and second end caps located at first and second ends of the tubes, respectively, the first end cap including a dialysis fluid inlet and a dialysis fluid outlet, the end caps and the tubes configured such that dialysis fluid can flow from the fluid inlet of the first end cap, through at least one first tube to the second end cap, and through at least one second tube back to the first end cap; a conductive wire wound around an outside of the conductive tubes; and electronics configured to supply power to the conductive wire, the wire forming a primary coil of a transformer, the tubes forming a secondary coil of the transformer.