Microsoft Excel spreadsheet add-ins for the R152a data and the psychrometric data, at any barometric pressure and in the air-conditioning and drying temperature ranges, were developed using appropriate governing equations. They were then used to simulate and analyse refrigerating, air-conditioning and drying processes in the Microsoft Excel environment by exploiting its automatic computation potentials. The packages allow one to determine the thermodynamic properties of R152a and humid air at any desired state, and to simulate and analyse refrigeration, air-conditioning and as well as drying processes. This, as a teaching tool, evokes the intellectual curiosity of students and enhances their interest and ability in the thermodynamics of R152a and humid-air processes. The developed Excel add-ins are also useful to the practising HVAC design engineer.