This paper outlines the benefits of large scale energy efficiency programs for new and existing buildings in Oman. In particular, an energy productivity analysis for these programs is carried out to encompass their overall impact for Oman’s economy. Over 75% of the total electricity consumed in Oman is attributed to buildings with almost 50% is due to household. First, a comprehensive optimization analysis is carried out using whole-building energy simulation to determine the best energy efficiency measures suitable to improve the energy performance of buildings in Oman. The economic and environmental benefits of a wide range of energy efficiency technologies are then evaluated. In particular, the impacts of different energy efficiency retrofit levels of existing buildings are the estimated on the energy productivity indicators for the building sector of Oman. The results of the analysis indicate that the implementation of a government funded large scale energy retrofit program for the existing residential building stock is highly cost-effective. In particular, it is found that a basic large scale energy efficiency retrofit program can provide a reduction of 957 GWh in annual electricity consumption and 214 MW in peak demand as well as over 660 k-ton per year in carbon emissions. © 2016 Elsevier Ltd