Stationary UV light therapy apparatus for treatment of vitamin D deficiency, comprising: a daylight and/or sunlight collector for collecting daylight and/or sunlight over a collector square area, a light transmission component for transmitting the light collected by the collector to the interior of a room of a building, an optical filter for transmission of UV-light included in the daylight and/or sunlight, and a light distributor for distributing the UV-líght over a square area of the room, wherein the square area is a part or all of the room square area and larger than the collector square area, and building comprising the same.
