The main purpose of this study is to investigate the relation between the condition of the supply air to a conditioned space and the indoor conditions, thermal comfort of occupants, annual energy consumption, environmental emissions and economics for different conventional air conditioning (AC) systems. Several commonly used AC systems are modeled to show that better thermal comfort and lower energy consumption can be achieved by employing efficiently controlled heat and energy recovery equipment. Six different AC system configurations are simulated for a small office building located in a very hot-humid climate (Miami, FL) using the TRNSYS building energy simulation platform. The indoor air conditions, percent of people dissatisfied (PPD), annual energy consumption, environmental emissions and economic analysis for the six AC systems are presented. Results show that the indoor temperature, indoor relative humidity and PPD can be maintained at 24+/-1oC (75+/-2oF), 50+/-5% RH and 10+/-5%, respectively, when heat and energy recovery equipment are integrated in a conventional AC system. Moreover, it is found that the life cycle cost (LCC) for such a system is 8% lower than a system that does not include a reheating coil, and heat and energyrecovery equipment.