Healthcare is one of the most complex and energy-intensive industries in the United States. Healthcare facilities consume 836 trillion BTUs, spending more than $8.8 billion, 1 to 3 percent of the operating cost, and 15 percent of their annual profits on energy each year. Retrofitting healthcare facilities, from a small renovation to building a new department, is considered an important approach to overcoming these challenges and provides an opportunity to implement energy conservation measures. This paper focuses on the energy consumption of three retrofit projects in three major hospitals and compares energy consumption before and after the retrofit. Based on the information collected from the Facility Departments, simulation models for the selected retrofit projects were developed and Energy Plus building energy simulation program was used to model the facilities. Monthly and annual energy simulation modeling results, before and after the retrofit, are compared and analyzed to identify key factors and opportunities for saving energy in existing healthcare facilities.