This paper presents a simulation method that has been used to study a number of aspects of HVAC process dynamics and control methods, including energy use and control tuning. The objective of this presentation is to extend the literature on the analysis of HVAC control processes primarily through (1) the description of the requirements for a flexible simulation methodology, (2) the discussion of the application of the simulation to the study of both temperature and relative humidity control process, and (3) examples of results from the use of the simulation method. In subsequent sections, each of these topics is addressed.