This paper presents a calibration process for determining an accurate EnergyPlus modeling methodology for a particular Phase Change Material (PCM) product consisting of PCM contained in pouches sandwiched between two sheets of plastic. Two test cells were constructed to control for the effect of the PCM product. Monitored test cell data were used to first calibrate an EnergyPlus model of the control test cell, and then to calibrate the EnergyPlus PCM module for the PCM product under investigation. The study results include calibrated PCM EnergyPlus module values for the PCM product. The results also demonstrate the importance of explicitly modeling heat transfer paths containing PCM separately from those not containing PCM.