The necessity for cooling elements in vernacular houses has emerged in response to the rise in global temperature. In India, vernacular houses receive more attention due to their traditional touch and simplicity in construction. Therefore, passive cooling features should be included to make the traditional vernacular houses more structured in different aspects. Among the many passive features that are available, selecting the right wall material is important. Five distinct wall materials that are burnt brick, dense concrete, cinder concrete, fly ash brick, and reinforced concrete cement were chosen for the study. Design builder 7.0.1.004 was used to create a single-room vernacular house with dimensions of 5 m × 5 m × 2.5 m, and energy plus 8.1 was used to perform the corresponding thermal analysis. The values of deciding factors such as relative humidity, room temperature, cooling load, cost, and CO2 emission were collected. These factor values were studied using Fuzzy TOPSIS multi-criteria decision-making (MCDM) technique in order to find the best wall material. From the results, it is observed that cinder concrete as a wall material in hot and humid climates was found to be the best suit which has been further confirmed using sensitivity analysis. Hence, cinder concrete can be used as a wall material while designing a vernacular house.