A method for simulating heat recovery systems using AirModel in implementations of the ASHRAE simplified energy analysis procedure was developed in this paper. AirModel, a simulation tool used to simulate the energy consumption of building heating, ventilating, and air-conditioning (HVAC) systems, was developed by the Energy Systems Laboratory (ESL) at Texas A&M University (TAMU) in the 1990’s. This program is capable of simulating single duct reheat systems and dual duct systems with economizer cycles. However, in certain buildings, energy savings techniques such as heat recovery systems are implemented but AirModel does not have a specific input to simulate this system. Presented in this paper is a method to simulate a heat recovery system using AirModel. An example of this methodology was used to simulate the HVAC system with a heat recovery system for the Biophysics and Biochemistry building on the TAMU campus.