The energy use in the world is increasing significantly owing to increase in per capita consumption of energy and growing population. Due to increased energy demand and the depletion of existing fossil fuel based sources, it is required to use the energy more efficient. Researches show that, hospitals represent approximately 6% of total energy consumption in the utility buildings sector. Heating, Ventilation and Air Conditioning (HVAC) systems are the major part of electrical energy consumption at the hospitals. In this paper, the research papers and practical studies on energy efficiency and energy saving potentials on HVAC systems at the hospitals are presented. Under the following sections, the latest literatures including research articles, conferences, e-books, handbooks and company reports interested in energy efficiency, energy saving and energy management HVAC systems are summarized. Variant Refrigerant Flow (VRF) technology enables greater energy efficiency and cost savings compared with traditional HVAC systems is also introduced. This detailed review also focuses on the payback periods of some projects on HVAC including the installation of cogeneration, trigeneration, chiller, new burners, heat exchangers and steam trap systems. (C) 2014 Elsevier Ltd. All rights reserved.