Abstract: Ventilation system (10) comprising resistive heating means (12) for heating gas flowing through the ventilation system (10) and means that are arranged to provide a 5 controlled, continuously variable AC voltage/current to at least part of the resistive heating means (12) of the ventilation system (10) to modulate the power (24) being supplied thereto and to enable continuous regulation of the temperature of gas flowing through the ventilation system (10).