This study provides fundamental data for optimal planning by analyzing key factors influencing microclimate and building energy loads. * to provide fundamental data for optimal planning. A total of 11 apartment layout types, including tower-type, flat-type, and mixed-type configurations, were analyzed using ENVI-met simulations. The results indicate that layout types significantly influence microclimate and energy consumption. Tower-type layouts enhanced wind flow, reducing surface temperatures and cooling loads. In contrast, dense flat-type layouts restricted airflow, leading to heat accumulation and increased cooling energy demand. Mixed layouts exhibited varied effects depending on the proportion of open spaces and high-density clusters. Additionally, south-facing layouts optimized solar radiation, reducing heating loads, whereas east–west-facing layouts experienced imbalanced solar exposure, increasing cooling demand by 15–20% in the summer. Horizontal parallel and staggered layouts improved ventilation efficiency and mitigated heat accumulation, making them effective strategies for enhancing microclimate and reducing energy consumption. This study confirms that apartment layout planning plays a crucial role in microclimate regulation and energy efficiency. The findings can guide architectural strategies to improve thermal comfort and reduce building energy consumption.