A method for heating one or more streams from a refinery process, chosen from the group of a crude tower inlet, vacuum tower inlet, catalytic reformer inlet, coker inlet, thermal cracker inlet and hydrocracker inlet. The method includes transferring, in a heat exchanger, heat from one or more streams from a petro-chemistry process, chosen from the group of a steam cracker charge gas, propane dehydrogenation charge gas and butane dehydrogenation charge gas to said one or more streams from a refinery process for obtaining one or more heated streams in which the temperature of said one or more streams from petro-chemistry process is above the temperature of said one or more streams from a refinery process before said step of heat exchanging has taken place.