This research investigates an existing heat exchanger system and subsequent modifications to condition process air. Three different methods will be examined to condition outdoor air to specified conditions; namely, the relative humidity and temperature of the air supplied being processed will be analyzed. The application requires supply air of a low humidity and a high dry-bulb temperature. The three methods under investigation differ primarily in how they humidify outdoor air which is subjected to preheating, cooling, and heating along with clean-steam humidification. Two important considerations when deciding the best approach for conditioning process air are the technical feasibility and the operating cost. An economic analysis of the heat exchangers will include total monthly and yearly costs for each system. The objectives are to determine operating costs and technical feasibility of each conditioning approach. An economic analysis comparing the variation of each component of the air handling system as well as an overall monthly and yearly cost assessment will be conducted. Due to the necessity of accurate inlet conditions of the process air, an in-depth investigation into the accuracy of humidity and temperature sensors will be analyzed. Specifically, the humidity sensor time response and accuracy, as well as absorption distance will be investigated. The effects of radiation from the heating and cooling coils on the temperature sensors will be examined. The effects of the humidity and temperature sensor errors are then discussed.