High residential energy consumption caused in part by lack of concern up until recently about the construction of efficient housing is an increasingly important issue nowadays. This study addresses the aforementioned problem by evaluating the advantages of the location of thermal insulation in housing walls, in order to reduce heating costs. To this end, retrofit systems were selected for three case studies, in which the most relevant aspects were characterized and subsequently simulated to carry out analyses of demand and thermal transmittance. Furthermore, solutions were evaluated under the assumption that they could be implemented using one of the currently existing alternatives, i.e. through housing improvement subsidies available in Chile. The benefits were measured using economic analysis techniques for building systems based on ASTM methodology. This evaluation was performed in order to verify whether a higher initial investment in a given system is compensated by the reduction of future costs, in this way identifying the most influential factors in this process.