A variety of retrofit options can be undertaken to reduce the growing energy consumption and ensure indoor comfort levels in housing. These offer specific solutions whose energy performance can be determined using building thermal performance simulations. This article presents a computer tool to help analyse alternatives to improve energy performance for single-family housing in the city of Concepcin, Chile. This software provides a novel procedure to manage thermal simulations, defining retrofit packages based on simulation results and that include price calculations. The software also allows estimates to be made using data from previously studied housing in the region. Background data are presented on the housing type under study as well as the proposed retrofit options and the analysis of some case studies. The software can suggest retrofit packages which provide reductions that range from a quarter to half the total energy demand at a cost of between 5 and 15% of total house value. These results show that the proposed tool works properly and provides good energy-efficiency retrofit recommendations for this type of housing, allowing it to be used as an innovative public dissemination instrument. Furthermore, it can be extended to manage simulations of other dwelling typologies or regions to support professional work.