Simulation-Based Thermal Performance Assessment and Economic Evaluation of Passive Retrofitting Strategies for Energy Load Reduction in an Existing Institutional Building

Abstract

Buildings account for a significant portion of global energy demand and carbon emissions, with space heating and cooling being primary contributors to operational energy use. Despite growing awareness of energy conservation imperatives, the integration of energy-efficient measures in newly constructed buildings remains limited, underscoring the substantial improvement potential within the existing building stock. This study focuses on Pakistan, where persistent energy shortages and frequent load shedding necessitate immediate and practical efficiency interventions. The research evaluates the effectiveness of passive retrofitting strategies in enhancing the thermal performance of an existing institutional building. A simulation-based approach was employed using Autodesk Ecotect 2011 to assess baseline thermal loads and quantify the impact of selected retrofit measures. Key interventions, including insulation enhancement, window upgrades, optimization of window-to-wall ratio, and energy-efficient lighting, were analyzed individually and collectively to determine their influence on annual thermal load reduction. An economic assessment was also conducted to evaluate feasibility based on cost and projected energy savings. The findings demonstrate that targeted passive retrofitting can significantly reduce building thermal loads while improving indoor comfort and economic viability. By incorporating climate-responsive strategies tailored to local conditions, this study provides practical recommendations to strengthen energy performance across Pakistan’s building sector and supports broader sustainable development objectives.