Chile presents an interesting building tradition related to adobe; indeed this material has defined the typical housing style of the nation from its colonial period. This building system have been traditionally based on walls of approximately 60 centimetres and supported by the compression force of the roof. Contemporary Chilean architecture has forgotten the material due to the handmade condition of the constructive system and the incapacity to satisfy the present structural requirements in a seismic country, relegating these practices to a few locations in rural zones. An innovating constructive system tries to modify this situation. By means of the combination of squares and steel meshes, the structure of walls, ceilings and floors are assembled, which are filled with adobe, releasing the material of any structural effort, allowing any thickness. However, wall thickness determines the thermal properties of the adobe constructions (especially in terms of thermal inertia and insulation) in the internal environment of dwellings. Simulations by means of the software TAS have been made to study the thermal behaviour of different wall thicknesses in different Chilean climates, which has demonstrated a good performance in terms of thermal lag, buffering temperature variations. Finally, this study explores different thicknesses of adobe walls to establish a balance between thermal performance and final cost.