An eight-page building simulation paper. For many buildings, continuous operation of the air conditioning system is not necessary for achieving thermal comfort during the occupied periods. Depending on the building's thermal and operational characteristics the air conditioning system may be operated during a specific period of time that may partially or completely cover the occupancy period. In this case, a considerable amount of energy can be saved without compromising comfort conditions provided that the correct operation strategy is implemented. In this paper, the impact of HVAC operation strategies on energy consumption and thermal comfort in an office building in Dhahran, Saudi Arabia is investigated utilizing the Visual DOE energy simulation program. The results are useful for exploring potential energy conservation opportunities in buildings characterized by intermittent occupancy while maintaining the requirements for thermal comfort.