Air electric heaters use the Joule effect of current to convert electrical energy into thermal energy to heat an object. Usually divided into direct resistance heating and direct resistance heating. The former's power supply voltage is directly applied to the object to be heated. When the current flow is overdue, the heated object itself heats up the ironing machine to generate heat. Objects that can be directly resistively heated need to be conductors, but have a higher resistivity. Since heat is generated by the object itself being heated, it is highly heated due to internal heating. Direct resistance heating needs to be made of special alloy materials or non-metal materials to produce heating elements. The heating elements generate heat energy, and the radiation, convection and conduction are transmitted to the heated object.