This European Standard specifies the boundary conditions and the prove methods for the determination of the thermal output of hot water floor heating systems as a function of the temperature difference between the heating medium and the room temperature. This standard shall be applied to commercial trade and practical engineering if proved and certifiable values of the thermal output shall be used. This European Standard applies to heating and cooling systems embedded into the enclosure surfaces of the room to be heated or to be cooled. This Part of this European Standard applies to hot water floor heating systems. Applying of Part 5 of this European Standard requires the prior use of this Part of this European Standard. Part 5 of this European Standard deals with the conversion of the thermal output of floor heating systems determined in Part 2 into the thermal output of heating surfaces embedded in walls and ceilings as well as into the thermal output of cooling surfaces embedded in floors, walls and ceilings. The thermal output is proved by a calculation method (Clause 6) and by a test method (Clause 9). The calculation method is applicable to systems corresponding to the definitions in EN 1264-1 (type A, type B, type C, type D). For systems not corresponding to these definitions, the test method shall be used. The calculation method and the test method are consistent with each other and provide correlating and adequate prove results. The prove results, expressed depending on further parameters, are the standard specific thermal output and the associated standard temperature difference between the heating medium and the room temperature as well as fields of characteristic curves showing the relationship between the specific thermal output and the temperature difference between the heating medium and the room. Compared to EN 1264:2008 a new Annex C concerning the calculation of the heat output for laminar flow has been included.