The global inefficiency of our energy systems forces us to no longer think energy but exergy, as exergy analysis integrates the notion of energy degradation. As thermal networks are a combination of multiple subsystems, exergy analysis is a relevant method to understand the interactions between them and to identify the sources of inefficiencies within the whole system. In order to precisely locate the latter, our models need to integrate exergy formulation as a function of design and operating parameters. Previous work presented an explicit analytic expression of the exergy losses in a distribution network as a function of geometric and thermo-hydraulic parameters. The distribution network was considered as an aggregated entity, assuming an average diameter and a total length. It was shown that, as thermal networks are transitioning to low temperatures, pressure drops are no longer negligible in the distribution system. Moreover, an optimal diameter exists, minimizing global exergy losses, as a function of the network’s nominal power. Given these observations, this work aims at generalizing the methodology previously developed to an entire network, by determining exergy losses on each segment, from the central production unit to substations. The previous model is extended to include energy systems and now describes more precisely the internal viscous dissipation sources (elbows, valves) in order to accurately describe the performance of low-temperature thermal networks. The topology and structure of blueCAD (blueFACTORY’s advanced thermal network in Fribourg - Switzerland) is used to highlight the impact of temperature level on the exergy losses of a global system and thereby determine the optimal temperature level.