Lambda device to optimize the energy absorbed by an ironing system comprises an iron (11), connected to a boiler (13) by means of a feed pipe (12). A resistance of the iron (20) and a resistance of the boiler (21) are associated to the iron (11) and the boiler (13). The iron (11) has at least temperature adjustment means (22), and at least a temperature detector (16) is present which detects the temperature (Tc) of the boiler (13). The device also comprises a processing system (17) able to receive the temperature values at least from the temperature detector (16) of the boiler (13), and is conditioned at least by the values detected by the temperature detector (16) in order to supply electric energy to the resistance of the iron (20) or to the resistance of the boiler (21).