Electric heater for heating, maintaining the temperature and permitting the circulation of a fluid, comprising: - a first base body and a second cover body, which are associated with one another and form an inner chamber; - a first mouth for the intake of the fluid into said inner chamber; - a second mouth for the discharge of the fluid from said inner chamber; - an electric resistor; - a first temperature sensor and - a control unit; characterised in that said first base body is provided with a plurality of fins (330 / 331, 332, 333, etc.) which extend inside the inner chamber; - that said electric resistor is embedded/incorporated in the mass of material which forms said first base body, wherein said resistor heats the first base body; - that said first base body incorporates the first sensor which is designed to measure the temperature of the first base body; - that said resistor and said first sensor are connected to the control unit; - that said control unit controls the signals received from the first sensor, and activates the resistor in a controlled manner in order to maintain the first base body at a certain temperature; - that said inner chamber has the shape of a box comprising a lower side, a left vertical side, a right vertical side, an upper side, and a depth; - that the first, intake mouth for the fluid is arranged in the lower area of said chamber and in the vicinity of the right side of the chamber; - that the outlet mouth for the fluid is arranged on the upper side of the chamber; - that the fins (331, 332, 333, 334, etc.) are oriented vertically inside said chamber and are spaced transversely from one another; - and that the fins (331, 332, 333, etc.) have a longitudinal - vertical side or foot which is associated with the first, base body. - a first base body and a second cover body, which are associated with one another and form an inner chamber; - a first mouth for the intake of the fluid into said inner chamber; - a second mouth for the discharge of the fluid from said inner chamber; - an electric resistor; - a first temperature sensor and - a control unit; - that said electric resistor is embedded/incorporated in the mass of material which forms said first base body, wherein said resistor heats the first base body; - that said first base body incorporates the first sensor which is designed to measure the temperature of the first base body; - that said resistor and said first sensor are connected to the control unit; - that said control unit controls the signals received from the first sensor, and activates the resistor in a controlled manner in order to maintain the first base body at a certain temperature; - that said inner chamber has the shape of a box comprising a lower side, a left vertical side, a right vertical side, an upper side, and a depth; - that the first, intake mouth for the fluid is arranged in the lower area of said chamber and in the vicinity of the right side of the chamber; - that the outlet mouth for the fluid is arranged on the upper side of the chamber; - that the fins (331, 332, 333, 334, etc.) are oriented vertically inside said chamber and are spaced transversely from one another; - and that the fins (331, 332, 333, etc.) have a longitudinal - vertical side or foot which is associated with the first, base body.