Proposing a layered model to develop sustainable affordable housing focusing on operation phase criteria

Today, access to sustainable affordable housing (SAH) for low-income families, especially in developing countries, has become challenging. To achieve SAH, previous research has focused more on strengthening the criteria of the design and construction stages, while the lack of a comprehensive model for the operation stage of the housing project life cycle remains a research gap. This study aims to provide a comprehensive model for achieving SAH through the realization of the operation stage criteria, focusing on energy savings. The research began with library studies, and 78 initial criteria were extracted for all life cycle stages. Using the Delphi method and 33 experts in six stages, 16 criteria related to the operation stage were selected. The criteria were ranked based on the experts' opinions on the importance of their impact, and then the solutions to achieve each criterion and the indicators for evaluating the solutions were obtained. The most important findings of the research are thermal insulation, the use of renewable energy, and climate-friendly design. Effective solutions include installing solar panels, insulating pipes, and using gray water recycling systems. Based on the findings, a proposed model with a three-layer structure, including Criteria, Solutions, and Indicators, is presented, which has the ability to continuously feed back and realize optimization. Using the model can reduce the costs of the operation phase and increase energy efficiency. It is suggested that future studies investigate the practical implementation of this model in real projects.