A radiator with reduced thermal inertia, based on the principle of phase changing, using a non-toxic, non-flammable fluid with reduced environmental impact. The radiator is provided by means of vertical pipes which engage a collector containing a pipe bundle-type exchanger with smooth or finned pipes, internally crossed by the thermo-vector fluid of the system, and which heat the intermediate vector fluid, bringing it to the biphasic state. The vector fluid evaporates, rising up the vertical pipes, flowing through the channels obtained in the extruded profiles of the vertical pipes themselves. The fluid re-descends, condensing on the walls, returning into contact with the hot pipes of the exchanger in order to re-evaporate and rise back up the vertical pipes. The film of condensed liquid provides the required heat exchange. The terminal is further equipped with mechanical parts which allow the inserting of temperature sensors for possible monitoring and control of consumption and system operation and control thereof, by means of on-board electronic control devices (electric valves) and remote devices suitably operating in radio-frequency.