A 55-m2 prototype for sustainable social housing was designed and built on a real scale for the Construye Solar 2019 contest. This house is composed of a convective evaporative cooling tower that faces north, which is built using prefabricated light wooden structure panels and OSB boards that contain insulating material made of lignocellulose (100% recycled material). The architectural design is simple and applies bioclimatic concepts in the most relevant spaces. It places humid areas to the south and, the air in the tower moves convectively, so the location of the bedrooms (2nd floor) is conceived to take better advantage of the heat at night. Natural ventilation flows are optimized using the vertical circulation space and a high-efficiency thermal envelope as a construction strategy, complemented with the incorporation of a partition with a non-ventilated air chamber inside, to increase the thermal resistance of the wall and distribute the ducts of the house to control the air tightness of the thermal envelope towards the outside.