Air duct and air system and methods and uses of said air duct and air system

An air duct in an air heating or air conditioning system, said air duct configured for connection with a voltage source and comprising:

• a wall comprising electrically conductive reinforcement elements integrated with the wall and arranged in separate parallel coils distributed at a distance from each other along a pitch of the air duct, wherein the wall of the air duct further comprises electrically conductive fibers distributed in the wall between the coils, and wherein a first coil of the parallel coils is configured as a cathode and a second coil of the parallel coils is configured as an anode to allow realization of an electric field therebetween and across the fibers;
• wherein said electrically conductive reinforcement elements are configured to generate heat in the wall of the air duct, in which the electrically conductive elements are integrated, upon application of electrical energy from said voltage source for prevention of thermal loss over the walls of said air duct;
• wherein said heat prevents heat loss from inside of the air duct to outside of the air duct, in case air inside the air duct is warmer than a surrounding outside of the air duct;
• and
• wherein said heat prevents heat entry from outside of the air duct to inside of the air duct, in case the air inside the air duct is colder than the surrounding outside of the air duct.