Abstract
This study investigates the impact of methodological assumptions on building performance modelling to select a façade design strategy based on expected Greenhouse Gas Emissions (GHG). A parametric simulation framework was employed to examine the effects of varying COP (Coefficient of Performance) and SEER (Seasonal Energy Efficiency Ratio) calculations, embodied emissions considerations, future climate scenarios, and decarbonization pathways on façade optimisation decisions. The framework was applied to case studies in Turin, Italy, and Eindhoven, Netherlands, revealing significant geographical variations in emissions reduction potential. The study shows substantial reductions in combined operational and envelope-related embodied GHG emissions when considering variable COP with progressive decarbonization pathways-up to 61.8% in Italy and 50.3% in the Netherlands. Key findings indicate that while absolute emission values exhibit substantial variation across methodologies, the relative ranking of façade design strategies remains predominantly consistent, particularly for wall configurations, where performance variations are typically limited to 2-4%. This observation suggests that simplified approaches, despite overestimating absolute emissions, can offer reliable guidance for comparing façade design alternatives during early-stage decision-making.