The present invention relates to a sterilization chamber (1) for sterilizing a web (3) of packaging material passing through the sterilization chamber (1), comprising an air-distribution system and heating elements (13a, 13b) arranged to heat the web (3), and a fan (11a, 11b) is provided at an end of the sterilization chamber (1), for driving a circulating flow therein, and where a heater (13a, 13b) is arranged at the outlet of said fan (11a, 11b). A method of operating the sterilization chamber is also disclosed, comprising the steps of a) feeding a packaging material web (3) through a sterilizing agent bath, and then into a sterilization chamber (1), b) driving a gas flow inside said chamber (1) with a fan (11a 11b), c) heating the air leaving the outlet of the fan (11a 11b) with a heater (13a 13b), and d) directing the flow from the outlet of the fan (11a 11b) towards the packaging material web (3) and on towards the inlet of the fan (11a 11b).
