Abstract: The invention relates to a method of drying with hot air where the drying is divided into at least two partial processes, in parallel or in series with each other, and the circulation flows of the two partial processes are conditioned to substantially different wet temperature levels, and the spent air in the partial process with higher wet temperature is heat exchanged with the circulation air in the partial process with lower wet temperature, in combination with that the spent air flows from the two partial processes thereafter are mixed with each other and caused to pass a heat exchanger common for the processes in order to preheat the supply air to the partial process with low wet temperature and after the passage through the heat exchanger to partially constitute supply air for the partial process with high wet temperature.