Rapid urbanization and rising energy consumption have intensified the need for innovative urban planning approaches that integrate nature and sustainability. This study examines the role of biophilic urban design in enhancing energy efficiency in the metropolis of Urmia. A quantitative analytical approach was employed, and data were collected through a specialized questionnaire administered to 360 experts in urban design, energy, and environmental fields. Structural equation modeling was used to evaluate causal relationships between biophilic design components and urban energy efficiency. The results indicate that all proposed pathways are statistically significant. Physical and environmental design features show the strongest direct effect on energy efficiency, followed by green spaces and accessibility and human–nature interaction. Psychological–social dimensions and biophilic management and innovation act as important mediators. Model fit indices confirm strong validity. The findings demonstrate that biophilic urban design improves energy performance through microclimate regulation, environmental quality enhancement, and institutional support, highlighting its potential as an integrated strategy for low-carbon urban development in cold and semi-arid cities.