The aim of this work is to investigate the potential of energy-efficient retrofitting strategies for residential buildings in Oman. An existing residential building located in hot climate with a built-up area of 212 m2 was selected. A building simulation model was created in DesignBuilder software. The model was then calibrated using actual electrical bills and measured weather data for year 2014. The calibrated model was subsequently used to evaluate different energy-efficient retrofitting strategies including the AC efficiencies, using insulations for both walls and roof, upgrading to LED lights, and improving the air tightness of the house. It was concluded that when combing the best strategy from each category, the annual energy consumption of the building can be reduced by as much as 42.5%. This significant reduction in energy consumption can help both the policy makers at governmental institutions and owners to move forward for large retrofitting campaigns to solve the current energy dilemma.