The purpose of this study is to compare energy use and CO 2 concentration for a multizone building utilizing three ventilation control strategies. The three strategies are occupancy-based demand controlled ventilation (DCV), carbon-dioxide based DCV and constant ventilation. The study compares the building's energy consumption using the three methods for summer, winter and transition seasons. To perform the study, an indoor air quality (IAQ) model was developed and used in conjunction with EnergyPlus to simulate the building. Experiments were conducted at the Iowa Energy Center's Energy Resource Station to validate the IAQ model. Results from the study show that occupancy based DCV requires the least amount of ventilation air which still meets the ASHRAE ventilation standard.