As India strives toward becoming a Viksit Bharat, it is essential to integrate sustainable development practices that harmonize modern scientific advancements with the enduring principles of our Indian Knowledge Systems (IKS). One such practice is retrofitting existing housing to meet Net Zero Energy (NZE) standards—where a building generates as much energy as it consumes. This approach is especially relevant in rapidly urbanizing cities like Nashik and Maharashtra, where energy demands are escalating and the need for environmental conservation intersects. By blending innovative technology with the wisdom of IKS, retrofitting can pave the way for a more sustainable, energy-efficient future for Nashik and beyond. This study examines the role of building simulations in enhancing energy efficiency for residential buildings in Nashik, India, aiming to achieve Net Zero Energy Buildings (NZEBs) for sustainable urban development. The research integrates passive design strategies, advanced insulation, and renewable energy systems using a systematic design methodology. Simulation tools assess thermal comfort, energy consumption, and renewable energy potential. The findings demonstrate that optimizing building orientation, incorporating passive cooling techniques, enhancing insulation, and utilizing solar energy can reduce energy demand by 33%, thereby achieving NZE performance. This approach significantly lowers carbon emissions and dependence on fossil fuels compared to conventional housing. The study offers a replicable, simulation-based framework for NZEBs tailored to Nashik’s hot & dry climate, providing valuable insights for architects, urban planners, and policymakers. It emphasizes the importance of early-stage simulations in designing energy-efficient, climate-responsive homes and contributes to India’s carbon neutrality and energy security goals.