Due to increasing overheating risk from the global warming, it is crucial to evaluate building performance, especially that of a subtropical terrace house with limited façade exposure, to ensure its future livability. The effectiveness of current cooling strategies has not yet been thoroughly analyzed by considering specific zone position in a terrace house and varying future weather scenarios in existing studies. This study quantifies livability of six typical zones in two types of terrace houses employing two cooling strategies during summer under historical and future weather scenarios. It considers two key outputs: annual heat discomfort hours and cooling Energy Use Intensity (EUI). Additionally, a global sensitivity analysis using Standard Regression Coefficients (SRCs) identifies the key variables. The results indicate that the future annual cooling EUI is projected to increase by around 150 kWh/m2, with discomfort hours reaching 80% during summertime. Furthermore, window-to-wall ratio, total length, and solar heat gain coefficients (SHGCs) of windows significantly reduce cooling EUI by 50–165 kWh/m2. However, most input variables have a minimal impact on heat discomfort hours, resulting only in a 0.7–7.2% reduction. This study provides an analytical framework for assessing the future livability and sustainability of subtropical terrace houses, facilitating the development of robust strategies during the early design stage.