The present paper describes a new method for the monitoring of a heating energy source efficiency, e.g., fuel, solid or gas burner from a preset value. The method utilizes the advantages of the information, electronics and telematics technology. This method utilizes the energy source deviation from a preset value based on the source's action or on its operation period per transferred energy cycle. The software and the hardware that is implemented could be used as a part of an energy source, e.g., burner-boiler or as a separate data logging system. Additionally, it could be used for the inspection of the energy efficiency in public or municipal buildings.