Buildings are significant contributors to global energy consumption and CO2 emissions, making it imperative to implement strategic intervention scenarios to reduce their energy and carbon footprint. Bottom-up physics-based Urban Building Energy Modelling (UBEM) tools are crucial for this goal. These tools provide quantifiable impacts of intervention scenarios on the building stock, supporting cities in developing roadmaps aligned with national and international environmental targets. This study simulates two intervention scenarios for a mixed-use district in Milan, Italy, using Urban Modelling Interface (umi). The first scenario focuses on renovating low-efficient buildings to meet the 2030 local regulation goals. The second envisions an operationally carbon-neutral district achieved through building envelope improvements and complete electrification of energy uses, aligning with the European Union’s target for climate neutrality by 2050. The impact of the proposed measures on heating energy use, primary energy, and operational CO2 emissions is assessed and compared to the current performance of the buildings. An economic analysis, considering Net Present Value and Payback Time, explores the financial viability of the interventions. This study provides actionable insights into effective decarbonisation strategies, offering a practical framework for policymakers. The findings can guide compliance with regulatory directives, enhance urban energy efficiency, and promote sustainable development.