This paper focuses on the sensitivity of heat losses in collective heat distribution systems using a simplified calculation method. The methodology considers several parameters influencing the performance of heat distribution systems. Hence, the thermal properties of the heat exchanger in the dwelling heating substation and the return temperature of sanitary hot water are considered. In addition, the recirculation control strategy, the length of service branch which is included or not in the recirculation as well as, the share in a building of dwelling heating substation with similar characteristic and control strategy are also taken into account. The present study assess the impacts of some potential variations in the input variables, on the conclusions of the methodology. A comparison of the sensitivity of heat losses in the heating distribution system between four different buildings typologies, i.e. with 13, 24, 25 and 49 apartments, is provided. In order to identify the influence of building typology and pipe layout in the heat losses calculation, for the four cases the sensitivity analysis was carried out. A study was conducted through sensitivity analysis by means of an experimental design, consisting of the combinations of parameters which were varied from the levels at which they were set. Results shows how sensitive the solution is in the face of different parameter values as well as under what circumstances the solution would change. The suitability of the improved method which allow more flexibility to consider different pipe layout characteristic within a heating distribution system was demonstrated
