On June 13th of 2005 an earthquake destroys most of the town “San Lorenzo de Tarapacá”, located in the north of Chile. This one shows a vernacular architecture directly related to a hot-arid climate where it is placed, since adobe is the main building material. However, due to the poor seismic performance of adobe, the loose of traditional handmade construction, and the poverty that affects the community threats the architectural heritage of San Lorenzo de Tarapacá. To confront these problems, a group of students of the Pontificia Universidad Católica de Chile developed a strategy for the town reconstruction, considering vernacular architecture in association with the internal environmental conditions for this specific latitude. This study tries to optimize the thermal performance of a prototype proposed as a reconstructed dwelling. For this purpose, simulations by means of TAS software have been made to study the thermal behavior of a paradigmatic heritage building, obtaining a comfort standard to this zone. Therefore, different solutions will be proposed in comparison with this standard, in terms of thermal comfort, resources economy and construction advantages.