Building energy performance is commonly addressed through architectural, envelope, and mechanical system strategies, while the role of structural engineering decisions remains insufficiently examined. In particular, structural form is often treated as a passive constraint rather than an active contributor to operational energy outcomes. This study investigates the impact of structural form on building energy performance through a controlled, performance-oriented comparative framework. Representative structural forms are analyzed under identical architectural, climatic, and operational conditions to isolate the effects of structural configuration and behavior. Structural response characteristics, including stiffness distribution and deformation patterns, are systematically coupled with operational energy performance indicators. The results demonstrate that structural form has an independent and measurable influence on energy demand, with cooling-related performance showing particular sensitivity to structural behavior. Forms characterized by balanced stiffness and controlled deformation consistently exhibit lower energy consumption and more uniform spatial energy distribution. The findings confirm that structural behavior mediates energy performance in a non-linear manner governed by serviceability thresholds. The study concludes that structural form should be recognized as a primary variable in energy-conscious building design, offering a structurally grounded perspective for integrated and performance-driven practice.