**Background:** There are some problems in assessment of operational efficiency of centralized heat supply systems. A prerequisite for the creation of this method of assessment is that there is no unified commonly recognized method of centralized heat supply system efficiency assessment, which makes it necessary to introduce a new parameter that can accurately assess the efficiency of such systems.

**Materials and methods:** We used practical results obtained in the process of developing and updating heat supply schemes of several municipalities of Vladimir region. We applied the method of fuzzy sets to develop the mathematical model of heat power supply to find the correct functional dependences between the parameters that describe heat supply systems. The numerical simulation was made in the software complex Matlab. The technical and scientific novelty of the proposed method consists in introduction of several parameters such as the level of automation and dispatching and the coefficient of heat supply system efficiency.

**Results:** A method has been proposed for the assessment of operational efficiency of centralized heat supply systems in small towns. This method allows determining the main and important parameters of centralized heat supply systems and calculating the efficiency based on the obtained values.

**Conclusions:** Based on the results of evaluating the proposed method, we can formulate the main problems of centralized heat supply systems and measures that can help improve their efficiency. The developed method is currently being tested on the existing heat supply systems and can be used by both the heat supply and operating organizations, government authorities of the municipalities and small towns.