A significant share of the global housing stock lacks minimum residential quality standards. This has prompted the emergence of schemes to meet the needs of current occupants and country-specific carbon targets. Energy retrofitting, in this context, is a cornerstone for initiatives aimed at improving the indoor environmental quality of residential buildings while reducing environmental impacts and costs associated with space conditioning. This study explores different energy retrofitting solutions to the CORVI 1020 scheme, an emblematic mass social housing scheme that was heavily replicated in Chile disregarding local environmental conditions. Building energy simulation and life cycle assessment are used to evaluate three retrofitting scenarios under four contrasting climatic conditions. These scenarios reflect conditions that can be achieved under current subsidized schemes, including moderate and high-performance envelope improvements, with and without a sunspace extension. The scenarios are finetuned to minimize heating demand in winter and overheating risks in summer. Overall, the high-performance solution without sunspace extension outperforms other scenarios across climates and metrics. This study contributes to the development of strategies to improve residential quality and environmental performance in mass housing from a multi-variable perspective.