In the Kingdom of Saudi Arabia (KSA), residential buildings' energy consumption accounts for almost 50% of the building stock electricity consumption. The KSA's economy relies heavily on fossil fuel sources, namely oil reservoirs, whose depletion will negatively affect the future development of the country. The total electricity consumption is growing by approximately 5-8% annually, which would lead to oil production and oil consumption being equal in 2035. Therefore, residential buildings need further assessment as regards their current energy consumption. This research used a survey to explore current user behaviour in residential buildings' energy performance in the city of Jeddah, KSA. The findings of the survey show that several factors impact the energy performance in residential buildings. First, the buildings' thermal properties were found to be poorly designed. Second, the cultural aspects (family member role and generous hospitality), and the majority of users within the buildings preferring a room temperature of below 24 • C, requires a massive amount of cooling due to the climate conditions. Third, an increase in user awareness has helped to slightly improve residential buildings' energy efficiency. Knowing the current high-energy-consumption sources and causes, being able to define opportunities for thermal properties' enhancement, and increasing user awareness of how to achieve self-sustaining buildings are essential.