An air purification device with ozone and find dust cleaning, and optionally heating, cooling and dehumidifying function, is formed for installation in a room of a building. The air purification device comprises a first air channel to supply fresh air and a second air channel to discharge extract air. The two air channels lead through a heat exchanger. The air purification device further comprises a third air channel which opens into the first air channel after the heat exchanger. An electric filter/ozone generator is arranged in the first air channel after the first inlet and in the third air channel after the third inlet. A first fan is arranged in the first air channel after the electric filter/ozone generator and a second fan is arranged before the active carbon filter. A control unit is programmed to operate in at least one first operating mode the second fan with a higher suction power than the first fan.