An electric heater includes a heating element, a heat transfer wall and a control module. The electric heater includes a fluid chamber, an inlet, and an outlet. The fluid chamber is in communication with the inlet and the outlet, the heat transfer wall is a portion of a wall part forming the fluid chamber, the heating element is fixed or limited to at least a portion of the heat transfer wall, the heating element is located outside the fluid chamber, and at least a portion of the heating element is in contact with the heat transfer wall. The electric heater includes a cover body wall, which is another portion of the wall part forming the fluid chamber. The control module is located outside the cover body wall, the control module is located outside the fluid chamber, the control module is electrically connected to the heating element.