Abstract: A heating assembly (100) for a chromatography system (1000) comprises primary and auxiliary heating tubes (110H, 120H) made of an electrically conductive material, and forming at least part of an inner and outer tube, respectively. The inner and outer tubes are mechanically and electrically interconnected. The primary and auxiliary heating tubes axially overlap at least along a subsection length (L) of the inner and outer tubes for transferring auxiliary heat from the auxiliary heating tube to the primary heating tube. The heating assembly comprises a pair of electrodes (130, 131), arranged for forming an electrical path (180) running in series through the primary and auxiliary heating tubes. The auxiliary heating tube comprises an extendible section (125) such as a bellows to axially extend or shorten for compensating any difference in thermally induced contraction or expansion, respectively, between the inner and outer tubes.