Today, the enthalpy method is most often used to study technological installations for energy efficiency. Exergy analysis gives the most complete and objective assessment of various types of energy. Study presents an experimental setup that simulates a heating system to which an exergy meter is connected. As a result of the experiment, it turned out that the amount of heat remains constant if the temperature difference between the inlet and outlet is constant. However, the exergy method showed that exergy increases with an increase in the inlet temperature (even with a constant temperature difference); therefore, fuel consumption also increases with an increase in the initial temperature. The heat meter was invented a long time ago, but the device for measuring exergy did not yet exist. The device will give an impetus for a more active development of exergy analysis.