Buildings are increasingly required to be efficient not just in their operation, but from construction to demolition. Thus, interest in natural construction materials with low embodied environmental impacts has increased, (re)inventing materials and components from vernacular architecture. Compressed Earth Bricks (CEBs) are an example of this kind of component. They are flexible in a wide range of applications and their natural features favour their usage as thermally massive elements to increase a building’s thermal inertia (TI). The ability to store heat during the day and release it later helps buildings in dampening thermal swings, making TI a good strategy for preventing overheating in offices usually characterized by critical internal loads. Previous studies highlighted the difference between the thermal behaviour results obtained with tests on the materials, like experiments in controlled climatic chambers and real-world applications. In this study, an application of CEBs is taken as a case-study to analyse the thermal behaviour of an earthen wall and the potential of coupling night ventilation to stabilize temperatures and increase indoor comfort. Comparing the results obtained in two different rooms, representative of lightweight and heavyweight earthen construction, it was possible to quantify the contribution of CEBs walls to the passive cooling strategy in office buildings, according to different ventilation profiles/scenarios.