Device for the decrease of fuel consumption in plants producing heat or energy and following reduction of emission in the atmosphere, obtained through an autoinduction phenomenon developed from thermomagnetic effect produces from copper wire coils (D1, D2, D3, D4) inserted around the central pipe (B). These copper coils (D1, D2, D3, D4) have different diameters and graduations and are independent each other. Each coil creates its own magnetic field and each magnetic field doesn't add itself to the others. Magnetic fields are alternate according the sequence: positive, negative, positive.