The building industry greatly impacts worldwide energy consumption. Residential energy use is significant, making it a key area for energy efficiency and environmental concerns. Building simulation tools are used to predict energy consumption. One shortcoming of simulations that are employed is that building occupants are assumed to behave uniformly. This study explores the potential of including variability of occupant behavior in building simulation models and its impact on the accuracy and reliability of simulation results. Actual consumption data and energy simulation results are used in tandem to investigate this topic. The first phase involved a even-week monitoring program in a dormitory where each room was equipped with an independent air-conditioning unit. The goal was to record and analyze electricity consumption that included this heating system. The second phase of the study explored occupant behavior. Each room was simulated using schedules representing three different behavior patterns: frugal, standard, and wasteful. Finally, simulation results are compared with actual data. The margin of error in the DesignBuilder standard scenario varies between 4% and 38%, while the average margin of error is 16%. In the frugal scenario, occupants could save 30% to 70% of their energy, with an average savings of 50% possible. For the standard scenario, rooms offer an average saving potential of 16%, and in the wasteful scenario, only one room offers a saving potential of 13%. The results of the study underlines the need for considering the variability in occupant behavior in simulation models.