Abstract: The invention relates to a de-humidifying system of a wind turbine. In a wind turbine tower de-humidifying system the tower comprises a chamber in its interior. The chamber comprises an electrical arrangement that admits waste heat. A first tube connects the interior of the chamber to the exterior of the tower, to allow air from the exterior of the tower to flow into the chamber. A second tube connects the interior of the chamber to the exterior of the tower, to allow air from inside the chamber to flow to the exterior of the tower. A valve is arranged in the second tube to open a passage between the second tube and the interior of the tower, to allow air from the chamber to flow into the tower.