An arrangement for producing hot water from solar energy, the arrangement comprising: an elongate solar collector device extending along a longitudinal direction from a first end to an opposite second end, the elongate solar collector device consisting of an elongate profile having walls that in between them define elongate cavities extending from the first end to the second end, the elongate solar collector device being arranged to house water in the cavities, the material of the elongate solar collector device being a polymer reinforced with an organic fiber material, wherein the amount of polymer ranges from 55 to 95 % and the amount of organic fiber material ranges from 5 to 45 %, wherein the elongate solar collector device being produced by extrusion, the elongate solar collector device having at least one first opening for receiving water into the elongate cavities, the at least one first opening being arranged at the first end and/or the second end, and at least one second opening for tapping off water, arranged at a middle part of the elongate solar collector device, the middle part being arranged at approximately the same distance from the first end as from the second end; and at least one valve adapted to be arranged in a respective one of the at least one second opening, the valve being openable and closable in order to be able to tap off any water housed in the cavities, when in use, the elongate solar collector device further comprising a first support onto which a first part of the elongate solar collector device proximate the first end is to be arranged, and a second support onto which a second part of the elongate solar collector device proximate the second end is to be arranged. an elongate solar collector device extending along a longitudinal direction from a first end to an opposite second end, the elongate solar collector device consisting of an elongate profile having walls that in between them define elongate cavities extending from the first end to the second end, the elongate solar collector device being arranged to house water in the cavities, the material of the elongate solar collector device being a polymer reinforced with an organic fiber material, wherein the amount of polymer ranges from 55 to 95 % and the amount of organic fiber material ranges from 5 to 45 %, wherein the elongate solar collector device being produced by extrusion, the elongate solar collector device having at least one first opening for receiving water into the elongate cavities, the at least one first opening being arranged at the first end and/or the second end, and at least one second opening for tapping off water, arranged at a middle part of the elongate solar collector device, the middle part being arranged at approximately the same distance from the first end as from the second end; and at least one valve adapted to be arranged in a respective one of the at least one second opening, the valve being openable and closable in order to be able to tap off any water housed in the cavities, when in use, the elongate solar collector device further comprising a first support onto which a first part of the elongate solar collector device proximate the first end is to be arranged, and a second support onto which a second part of the elongate solar collector device proximate the second end is to be arranged.