In this study, the thermal performance of various shapes and geometries of atriums in buildings is examined under various conditions. The goal of the study is to assess the impact of the atrium shape on the building total energy consumption and to identify the most energy-efficient atrium design. The study focuses on four different central atriums types with square and rectangular geometries which have same areas, use, schedule, controls, occupancy, and construction. The atriums exhibit different aspect ratios (length to width). Four cities in United States are selected to represent primary climatic regions of hot-dry, hot-humid, cold, and temperate. Besides, the atrium height, the atrium glazing type, and the glazing ratio are varied throughout the simulation process. buildings models are constructed using the DOE-2.1E building energy simulation program. The results of this study indicate that in general, the total energy consumption of the narrow, elongated atrium or the rectangular atrium with high ratio of length to width is significantly greater than the square shaped atrium. (c) 2012 Elsevier B.V. All rights reserved.