Energy efficiency improvements of renovated district heating and cooling (DHC) plants were evaluated by simulation. In this paper, simulation models for the original and renovated plants were developed using the equipment specifications of the plant before and after renovation. The model accuracies were examined by comparing with measured data from plant operations. This comparison resulted in modifications of certain parameters related to the chiller operational control and chiller efficiency. The simulation model quantified the total annual energy efficiency improvement and the contribution of each piece of equipment replaced.