Nowadays, providing housing for the low-income groups of society is a concern for governments, especially in developing nations. An attempt has been made to recognize the most significant real criteria for reducing housing project costs and providing affordable housing for them by studying previous research and analyzing the collected information. First, the resources compiled in the field of affordable housing were reviewed, and data were gathered. Next, qualitative and quantitative questionnaires were provided, and the experts’ answers were analyzed in three steps (Delphi technique, AHP techniques, and case studies). By analyzing the findings, it was concluded that the current approaches in housing planning need to be revised to achieve the government’s goals and policies. Therefore, the physical indicators and patterns of vernacular and traditional houses in different climatic regions should be known and changed in the next step according to the needs of the modern world. The adaptation of today’s architecture from the vernacular architectural features of the past is one of the important things that should be considered. In this research, the consideration of housing preparation for low-income groups and reducing housing project costs, by identifying the most important effective criteria mentioned in other previous studies, is the novel contribution of this research.