Problem statement: The concept of “city” and the relationship between cities and their environment remain contentious issues within the current body of research. The introduction of the concept of “eco-comfort”, which simultaneously addresses both subjective and objective dimensions, has offered a novel avenue for advancing environmental knowledge, particularly in the realm of urban planning. The present study seeks to address the following question: How can we achieve “eco-comfort” criteria by differentiating between the concepts of “eco-comfort” and “livability” in the fields of environmental sciences, urban planning, and urban development? What insights do experts in this area provide?Research objective: This research aims to define and distinguish between the concepts of “livability” and “eco-comfort,” while systematically reviewing and reformulating eco-comfort criteria based on expert opinions. The goal is to establish a conceptual framework that can be integrated with other novel concepts related to urban development.Research method: The research is based on Highperformance ARCHITECTURE Theory to outline a concept for future cities, the present study used a systematic review, three-round Delphi method, and Shannon technique to formulate, scrutinize, and refine eco-comfort criteria, taking into account the conceptual hierarchy, which includes goal, approach, strategy, structure, component, criterion, and indicator.Conclusion: The results reveal that eco-comfort, encompassing 16 criteria developed, is a multifaceted concept that is not limited to the notion of livability. The weighting of these criteria using Shannon entropy indicates that criteria such as spatial justice, green transportation network, and efficient governance substantially influence the eco-comfort structure of a city. This suggests that achieving eco-comfort in urban spaces necessitates an alignment between physical components and socio-cultural values, supported by effective governance. The findings not only offer an operational model for assessing the eco-comfort of cities but also create opportunities for thoughtfully developing political and physical interventions to enhance it.