The scope of this work covers a proposal for the implementation of sustainable, low-cost, environmentally friendly, and affordable housing for low-income people. This paper aims to address the current housing issues, namely that many people lack decent housing and that the built houses are usually of a poorly sustainable nature. The work consists of three main parts: an evaluation of housing sustainability, measurement of parameters related to their internal comfort and a simulation of thermal enclosure with the COMSOL Multiphysics ® software. An important objective is to propose a sustainability assessment format, which, besides being explained in detail, is presented in a percentage scale for ease of understanding. This work seeks a methodology for evaluating the level or degree of sustainability for the construction and inhabitation stages of housing. Using a prototype constructed with polyethylene terephthalate (PET) bottles, temperature and humidity were measured. There was a contrasting behavior of these two parameters, which tended towards an inverse behavior, except on cloudy or rainy days. The roof of the prototype contained some waste materials that provided thermal insulation: galvanized steel, polyethylene bags for upcycling as waterproofing, PET bottles, soil and endemic plants (green roof). The results obtained in the simulation are in accordance with the real internal behavior of the prototype.