Energy retrofit design approach for the attainment of net zero energy residential buildings in hot and dry climates

The increasing energy demand of the Indian construction sector highlights the urgent need for energy-efficient retrofit strategies for existing buildings. This study presents an integrated framework for transforming an existing residential building in the hot and dry climatic regions of western India into a near net-zero energy building. The methodology combines Building Information Modelling and simulation tools, including Revit, Design Builder and MATLAB, to optimise building envelope components and evaluate energy performance. Sustainable retrofit alternatives for wall, roof and floor materials were analysed to minimise cooling loads and improve thermal comfort. The results demonstrated that optimised passive design interventions reduced overall building energy consumption by 33.46% during the monitoring period from December 2022 to January 2024. Further integration of rooftop photovoltaic panels reduced annual electricity consumption from 9330 kWh to 840 kWh, significantly improving building energy performance. The proposed framework achieved a reduction in Energy Use Intensity from 38.88 kWh/m2·year to 3.58 kWh/m2·year, representing an overall reduction of approximately 90.8%. The novelty of the study lies in the development and real-time validation of a generic energy retrofit methodology applicable to residential buildings located in hot and dry climatic zones worldwide, integrating envelope optimisation, operational validation and renewable energy systems for sustainable building transformation.