1 . A roof window system configured for being mounted in an opening in a roof structure of a building, said roof window system including a ventilation unit configured for being mounted adjacent to a roof window and adapted for providing ventilation of an interior of the building in which the roof window is mounted,
where said roof window comprises at least one frame defining a frame plane and including a pane mounted in said at least one frame, the at least one frame comprising a top frame member intended for being located highest in a mounted state when seen in a direction of inclination of the roof structure, a bottom frame member opposite the top frame member, and two side frame members extending between the top frame member and the bottom frame member, said top frame member, said bottom frame member and said two side frame members together form a window structure delimiting a frame opening and each having an interior side intended for facing an interior in the mounted state, an exterior side intended for facing an exterior, an inner side facing the frame opening and an outer side facing away from the frame opening, where the ventilation unit is configured for being arranged primarily adjacent to the outer side of a corresponding frame member, and the ventilation unit comprises a frame facing side configured for being arranged adjacent to or at the interior side of said corresponding frame member and in that the roof window system further comprising a ventilation panel allowing air passage from one side of the ventilation panel to another side of the ventilation panel, thereby defining an intended air flow direction, said ventilation panel being configured for facing the interior of the building and extending away from the interior side of the corresponding frame member adjacent to which the ventilation unit is mounted.
2 . A roof window system according to claim 1 , wherein the ventilation panel is configured such that the ventilation panel does not extend below a window frame plane defined by the inner side of the corresponding frame member in a mounted state.
3 . A roof window system according to claim 1 , wherein the ventilation panel is configured such that the intended air flow direction is extending substantially perpendicular to the frame plane in the mounted state.
4 . A roof window system according to claim 1 , wherein the ventilation unit is configured to be arranged at the top frame member.
5 . A roof window system according to claim 1 , wherein the ventilation panel is configured for being accommodated in a groove in the frame adapted for receiving a lining panel and/or the ventilation panel is provided with a groove configured to accommodate a lining panel.
6 . A roof window system according to claim 1 , further comprising a lining panel, wherein the ventilation panel is integrated in the lining panel.
7 . A roof window system according to claim 1 , wherein the ventilation panel is comprising a grating and/or a closure.
8 . A roof window system according to claim 1 comprising a ventilation assembly comprising the ventilation unit that is configured for being arranged adjacent to the outer side of the corresponding frame member and a housing, said housing accommodates the ventilation unit.
9 . A roof window system according to claim 8 , wherein the housing comprises a solar cell mounted on an exterior side of the housing for supplying electricity to the ventilation unit.
10 . A roof window system according to claim 1 , further comprising a sash, comprising a top member, bottom member and two side members defining a sash plane, wherein the ventilation unit is configured for being mounted such that the ventilation unit, the corresponding frame member adjacent to which the ventilation unit is mounted and the corresponding sash member are located substantially in continuation of each other when seen in the direction of the frame plane in the mounted state.
11 . A roof window system according to claim 1 , wherein dimensions of the housing are chosen such that a length of the housing is parallel to a length of the corresponding frame member which the ventilation unit is adjacent to and does not exceed the length of the corresponding frame member, and a height of the housing is parallel to a height of the corresponding frame member which the ventilation unit is adjacent to and does not exceed the height of the corresponding frame member.
12 . A roof window system according to claim 1 , wherein the ventilation assembly further comprising an input and exhaust of air and/or a ventilator and/or an air purifying filter.
13 . A roof structure including a roof window system, said roof window system including a ventilation unit configured for being mounted adjacent to a roof window and adapted for providing ventilation of an interior of the building in which the roof window is mounted,
where said roof window comprises at least one frame defining a frame plane and including a pane mounted in said at least one frame, the at least one frame comprising a top frame member located highest when seen in a direction of inclination of the roof structure, a bottom frame member opposite the top frame member, and two side frame members extending between the top frame member and the bottom frame member, said top frame member, said bottom frame member and said two side frame members together form a window structure delimiting a frame opening and each having an interior side facing the interior, an exterior side facing the exterior, an inner side facing the frame opening and an outer side facing away from the frame opening, where the ventilation unit is primarily arranged at the outer side of a corresponding frame member, wherein the ventilation unit comprises a lower side configured for being arranged adjacent to or at the interior side of said corresponding frame member, and the roof window system further comprising a ventilation panel facing the interior of the building and extending away from the interior side of the corresponding frame member.
14 . A method of providing ventilation for a building using a ventilation unit configured for being mounted adjacent to a roof window,
where said roof window comprises at least one frame defining a frame plane and a pane mounted in said at least one frame, the at least one frame comprising a top frame member intended for being located highest in a mounted state when seen in a direction of inclination of a roof structure, a bottom frame member opposite the top frame member, and two side frame members extending between the top frame member and the bottom frame member, said top frame member, said bottom frame member and said two side frame members together form a window structure delimiting a frame opening and each having an interior side intended for facing an interior in the mounted state, an exterior side intended for facing an exterior, an inner side facing the frame opening and an outer side facing away from the frame opening, said method comprising the steps of: arranging the ventilation unit adjacent to the outer side of a corresponding frame member, said ventilation unit being adapted for providing ventilation of an interior of the building, arranging a ventilation panel so that it faces the interior of the building and extends away from the interior side of the corresponding frame member adjacent to which the ventilation unit is mounted, and passing air through the ventilation panel from one side of the ventilation panel to another side of the ventilation panel in an intended air flow direction using the ventilation unit.
15 . A roof window system according to claim