Natural ventilation is an important passive cooling strategy. Using cool night air can cool the building structure and lower air conditions energy consumption. However, there are obstacles in using this cooling strategy, including high relative humidity, pollution, limitations in the thermal storage of the building, and low nighttime air temperature. This paper investigates energy savings by indirect ventilation to pre-cool buildings and reduces humidity. The nighttime ventilation strategy is based on optimizing the use of direct and indirect natural ventilation through an air-to-air heat exchanger. This strategy has been tested at the Beliveau House in Blacksburg, Virginia. Simulation results suggest that the indirect ventilation strategy at the Beliveau House reduces inside relative humidity on hot humid summer days by 20%, and the total summer cooling load by 38% when compared to the existing condition.