NOVELTY - A pre-insulated pipe for district heating or district cooling, has a layer of polymeric material surrounding the insulating material. The layer of polymeric material includes a material from polyvinylidene chloride, polyacrylate, and/or ethylene vinyl alcohol. The material is permeable to water or water vapor and has better properties than polyethylene for resistance against diffusion of oxygen and carbon dioxide.    USE - For district heating or district cooling (claimed).    ADVANTAGE - The inventive pre-insulated pipe has increased insulation properties especially at a long-term basis.    DETAILED DESCRIPTION - A pre-insulated pipe for district heating or district cooling, comprises a medium conveying pipe, an insulating material surrounding at least a part of the length of the medium conveying pipe and a jacket pipe at least partly surrounding the insulating material. It comprises a layer of polymeric material surrounding the insulating material. The layer of polymeric material comprises a layer of a material or combination of materials being permeable to water or water vapor and having better properties than polyethylene for resistance against diffusion of oxygen and carbon dioxide. The material includes polyvinylidene chloride (PVDC), polyacrylate (PA), or ethylene vinyl alcohol (EVOH). An INDEPENDENT CLAIM is also included for a method of manufacturing a pre-insulated pipe, comprising at least partly surrounding the insulating material with pre-insulated pipe having a layer of polymeric material. The polymeric material comprises a laminate in the form of a sheet material. The jacket pipe by extrusion, and the laminate is placed inside the extruded jacket pipe in a simultaneous operation including continuous folding. The folding involves placing the laminate with overlapping side edges in a tubular shape. A string of a meltable glue material is placed along and between the overlapping side edges, and the side edges are joined by heating the glue. The heating step is provided by residual heat from the extrusion of the jacket pipe.