Abstract: A process for operating a double furnace installation having two arc furnaces connected via a line, a power supply, a device for charging material, and an arrangement for extraction and purification of gas. The process including the step of connecting a first one of the two furnaces with the power supply for melting a charge located therein, completely cutting off a second one of the furnaces from the power supply. The second furnace is then charged with charging material and is closed with a cover. Flue gas located in the closed second furnace is sucked out above the burden column and flue gas is sucked out of the first furnace above the surface of the melted charge through the second furnace via the connection line provided between the two furnaces. A flue gas connection of the first furnace to the gas purification arrangement is interrupted while the flue gas is being sucked out of the second furnace while feed air is simultaneously taken on in the region of a cover of the first furnace.