As a significant feature of traditional dwellings and modern rural buildings in China, traditional Chinese cavity walls have always been valued for their material efficiency and thermal performance. However, the hygrothermal implications of their irregular cavity geometries—shaped by diverse bond patterns—remain underexplored, which affect the structure's durability and thermal efficiency over time. This study investigates the hygrothermal performance of traditional Chinese cavity walls using Heat, Air, and Moisture (HAM) simulations using both one-dimensional (1D) and two-dimensional (2D) simulations. Due to their complex, non-vented geometries and variable material interfaces, these walls present significant challenges for accurate modeling. The research evaluates different simulation approaches for non-vented cavity wall simulation, and explores how airgap interact with material characteristic. Results show that simulating non-vented cavities as homogeneous material layer with equivalent thermal conductivity can effectively represent the hygrothermal response through a cavity wall. Simplified 1D models underestimate moisture accumulation and mold risk, particularly at critical interfaces. In contrast, 2D simulations capture localized effects more accurately, especially in walls with continuous airgaps and variable bonding patterns. The findings underscore the importance of detailed modeling for reliable hygrothermal risk assessment and provide guidance for selecting appropriate simulation methods in heritage and climate-sensitive construction contexts.