In the design of packaged air conditioning equipment, it is found that packaging and installation requirements can often lead to maldistribution of airflow pattern at the approach to, and the discharge from the heat exchanger and other components, which can result in low heat exchanger performance. CFD modeling of airflow and heat transfer in a specified packaged unit is formulated to predict airflow pattern in the unit medium near the evaporator and centrifugal fan. Re-circulation and stagnant areas in the flow field are investigated in the predicted model. Experimental validation of the CFD model is conducted by performing measurements of actual flow characteristics (velocity, pressure and temperature) at different regions in the flow field. A simple parametric study is introduced by identifying the different geometric design parameters affecting airflow distribution in the unit. They are related to the change of components positions in the unit, which produced different thermal and flow performance in comparison with the original configuration.