Hybrid Optimization Model for Electric Renewables (HOMER) is one of the tools used by the World Health Organization (WHO) for designing renewable energy health facilities. This paper demonstrates the depth of the software application and instructs health workers (step by step) on how to model and simulate (design) renewable energy health facilities with HOMER by using hypothetical off-grid health facilities at various geographical locations which were chosen to reflect the various climatic conditions in Nigeria as the case studies. This tool (HOMER software) was used to design an optimal hybrid power system based on comparative economic and environmental analysis. Simulation was run on each of the case study sets of data and results (both the graphical and tabular output) were provided. The findings of the study were organized and presented as a supplementary data, and the results could aid in the planning of energy system for health facility projects in Nigeria.