This book offers an analytical review of psychrometric processes through EES (Engineering Equation Solver). Several problems are solved using equations and the corresponding psychrometric chart. The aim is to facilitate the study of the principles of psychrometrics, in a gradual and progressive manner. As the resolution of certain parameters calls for a numerical solution, a software tool that simplifies the calculation process was developed, based on the equations shown. In this book students of engineering are encouraged to use new techniques to solve problems related to thermodynamics, and to possibly develop their own applications. The book is organized into six chapters. The first chapter gives a brief summary of program management for the student. The second chapter defines the parameters of moist air for later collection by psychrometric equations and diagrams, as reflected in chapters three and four. The fifth chapter defines the main psychrometric processes that are commonly used in air conditioning systems, while the sixth chapter contains a series of exercises that facilitate self-learning by the reader.