What drives district heating network costs? A global sensitivity assessment

District heating networks are a key enabler of renewable energy integration in urban areas. However, their deployment is often constrained by high upfront investment costs, making cost-efficient design essential. This work applies a global sensitivity analysis to systematically assess how technical and economic parameters influence the levelized cost of heat, with a focus on piping network design. First, a comprehensive characterization of the design optimization model’s input parameters is performed, including load profiles of three consumer types and detailed piping cost structures. A two-stage global sensitivity analysis is then applied to a representative urban district with 4250 heat sinks and a total energy demand of 174GWh/year, with uncertain peak thermal power demand, to quantify the variability in design outcomes due to parametric uncertainty. The variability in heating costs attributed to piping ranges between 20–170€/MWh, primarily driven by the depreciation rate (ST=0.62), specific piping investment cost (ST=0.30), and piping lifetime (ST=0.04), in descending order of influence. Insulation standards and their cost uncertainty emerge as secondary sensitivity drivers (ST=0.02), while the maximum specific pressure drop and the temperature difference between the supply and return lines play a comparatively minor role, collectively accounting for ST<0.01. The results highlight insulation standards as a high-leverage decision for cost-efficient designs, while policymakers must incentivize capital-cost-reduction mechanisms and large-scale deployment to lower centralized heating costs.