OPTIMIZING ENERGY PERFORMANCE IN PAKISTANI COMMERCIAL BUILDINGS: A COMBINED AUDIT, SIMULATION, AND ECONOMIC EVALUATION OF PASSIVE COOLING RETROFITS IN PAKISTAN

Abstract

Buildings account for approximately 40% of global primary energy consumption and one-third of total CO₂ emissions. In Pakistan, an average energy shortfall of 5,000 MWe drives chronic load-shedding, yet two-thirds of national electricity is consumed by the building sector. This research presents a comprehensive energy performance analysis of a representative mixed-use commercial building in Lahore through three complementary methods: (i) an ASHRAE Level-2 equipment energy audit establishing a baseline Energy Use Intensity (EUI) of 80.1 kWh/m²/year; (ii) BIM-integrated Energy Plus simulation of five passive cooling retrofit scenarios; and (iii) lifecycle economic evaluation at 2024 LESCO tariff rates. Results show that high-performance glazing, wall insulation, cool roof coating, natural ventilation enhancement, and external shading — applied in combination — reduce annual cooling energy by 41.8% and lower peak demand by 15.4 kW. All five measures achieve positive net present value over a 20-year horizon, with simple payback periods of 1.4–5.7 years. The combined package yields an IRR of 18.9%, exceeding prevailing commercial borrowing rates. Findings provide a replicable decision-support framework for engineers, building owners, and policymakers pursuing energy security in Pakistan's largely unretrofitted building stock.