The evaluation of buildings in real conditions of use, or post-occupancy evaluation, is the systematic study of buildings with the objective of determining their performance once they are inhabited; it is a process of review and identification of successes and failures in order to improve the conditions of existing buildings and to feed future designs. Nowadays, the construction industry in Colombia does not have feedback processes regarding the operation of a building. The research presented below proposes the HEPO post-occupancy assessment tool, which is oriented to the analysis of buildings in phase of use, in terms of meeting the needs of the inhabitants, the consumption of resources associated to the use, and the conservation of the qualities of the materials in time. In order to verify the effectiveness of the tool, this is validated in five collective height housing projects in the city of Medell´ın, Colombia.