Heating districts have become one of the key infrastructures to efficiently and sustainably supply heat to consumers. With the current climate change crisis, not only are heating districts of the essence but their efficient and optimized operation as well. To analyze and achieve such an optimization, transient simulations of heating districts are needed. These simulations are a means of upgrading older town networks to smarter energy grids as well as an effective tool for the planning and building of newer heating networks. Therefore, this work presents an easy simulation method for the transient simulation of heating districts based on a control theory approach. The simulation method can calculate multiple-loop networks as well as non-looped networks and correctly predict how a heating network can behave over time. Additionally, this approach allows for the inclusion of new renewable energy sources into existing heating networks and to simulate the resulting network behavior. The method was tested on five different testcases involving a single-loop network, a multiple-loop network, and a real-life non-looped network. In each case, the calculated massflows were validated with the software Epanet (Version 2.2), while the simulated temperatures were compared to the theoretical steady-state values as well as the theoretical times of arrival of each heating network. The simulation results present a good approximation in each testcase. Finally, the limitations of the method are discussed, and a recommendation for the usage of the approach is given.