GenMix is a MATLAB based software tool to successfully assess professionals, promoters or companies in the selection of the best renewable-distributed generation-mix suitable to be installed in residential buildings considering technical, economic and reliability aspects. GenMix is capable to model the hourly electric demand profile of different kind of residential building considering the profile of their occupants. In addition is able to model photovoltaic and wind generators as well as other non renewable power sources like for instance fuel cells or diesel generators. The software is able to model the interaction between tha loads and the generators and the accumulation system battery based to estimate the percentage of demand that can be covered with self-supply, but it can also estimate the amount of energy that must be imported from the grid, the number of hours that the buildings can be fed with their own generation and it automatically drives a reliability and economical analysis of the proposed scenario. All the software features are described in the User Guide.GenMix was developed by Edwin Xavier Dominguez Gavilanes and Felix Manuel Lorenzo Bernardo under the supervision of Prof. Pablo Arboleya and is distributed under GPL license.