A support arrangement, preferably for a ventilation system comprising an air channel which is supported by the support arrangement, which support arrangement comprises: - a arm construction comprising two arm sections, a first arm section and a second arm section arranged in extension of each other, - a first joint connecting said two arm sections (103, 104), wherein said first joint comprises a first joint part attached at the first arm section and a second joint part attached at the second arm section, where said joint parts are connected with each other through a shaft passing through the first and second j oint part, and wherein the first and second j oint part can be rotated relative to each other around an axis of rotation formed by said shaft, - a second joint connecting said support arrangement with a fixed support, which second joint holds and maintains a basic position of the support arrangement so that different positioning of the support arrangement is possible, - a balance arrangement comprising a tension construction having a first and a second end, and wherein - each arm section (103, 104) comprises a hollow profile (108, 109) and wherein the first and second joint parts (110, 111) of said first joint are mounted in said hollow profiles (108, 109), characterized in - that the balance arrangement is arranged between the first and second arm sections, - that the tension construction has a first and a second attachment means (118, 119) for attaching the first and second end of the tension construction directly to the two arm sections (103, 104), and - that the first arm section comprises a protruding part which is arranged in a plane perpendicular to the axis of rotation and which protruding part protrudes from said first arm section to a position outside a joint region between the two arm sections (103, 104) where the first joint is arranged, - that a first fixture means is arranged at the protruding part, which first fixture means cooperate with the first attachment means at the first end of the tension construction, - that the second arm section comprises a second fixture means cooperating with the second attachment means at the second end of the tension construction, and - that the first and second fixture means (120, 121) allow a relative rotation of the arm sections (103, 104) in an angle in an interval between 25° and 180° as measured between a longitudinal axis (128, 129) of the two arm sections (103, 104). - a arm construction comprising two arm sections, a first arm section and a second arm section arranged in extension of each other, - a first joint connecting said two arm sections (103, 104), wherein said first joint comprises a first joint part attached at the first arm section and a second joint part attached at the second arm section, where said joint parts are connected with each other through a shaft passing through the first and second j oint part, and wherein the first and second j oint part can be rotated relative to each other around an axis of rotation formed by said shaft, - a second joint connecting said support arrangement with a fixed support, which second joint holds and maintains a basic position of the support arrangement so that different positioning of the support arrangement is possible, - a balance arrangement comprising a tension construction having a first and a second end, and wherein - each arm section (103, 104) comprises a hollow profile (108, 109) and wherein the first and second joint parts (110, 111) of said first joint are mounted in said hollow profiles (108, 109), characterized in - that the balance arrangement is arranged between the first and second arm sections, - that the tension construction has a first and a second attachment means (118, 119) for attaching the first and second end of the tension construction directly to the two arm sections (103, 104), and - that the first arm section comprises a protruding part which is arranged in a plane perpendicular to the axis of rotation and which protruding part protrudes from said first arm section to a position outside a joint region between the two arm sections (103, 104) where the first joint is arranged, - that a first fixture means is arranged at the protruding part, which first fixture means cooperate with the first attachment means at the first end of the tension construction, - that the second arm section comprises a second fixture means cooperating with the second attachment means at the second end of the tension construction, and - that the first and second fixture means (120, 121) allow a relative rotation of the arm sections (103, 104) in an angle in an interval between 25° and 180° as measured between a longitudinal axis (128, 129) of the two arm sections (103, 104).