Abstract: The present invention proposes a process and a device which permit to improve the efficiency of energetic gas turbines operating in user regions with outside temperatures from −5° C. to +5° C. Unlike in the state of the art, no heat is withdrawn in this connection from the gas compressor (3) when the heat requirement rises in the overall intake system, but successively by using first the off-air heated by the generator (2) for heating the intake air in the intake duct (12, 12′) and subsequently withdrawing additional heat in the form of the heat of an off-heat system (8) generated at the end of the heat circulation. When additional heat is required, heat can be withdrawn from the compressor (3) via a bypass conduit (20).