When comparing the efficiency gross of the same units operating under different conditions, or the same unit for different periods of time, often does not take into account that these values are obtained under different conditions. It is well known that the efficiency of the boiler unit depends on the heat load of the boiler. As a rule, the value of efficiency maximum at moderate loads of the boiler unit and then with increasing heat load gradually decreases according to a law close to linear. Thus, it is possible that for a unit with a better technical condition, an efficiency value will be obtained that is lower than that of another unit operating in more favorable conditions. There is also ambiguity in the presentation of the efficiency dependence. boiler unit from heat load. The paper studies the issue of the features of using the normalized heat load to determine the level of energy efficiency of a boiler unit based on the TVG-4r boiler of a small quarterly boiler house. It is shown that a feature of using the reduced efficiency, which is determined depending on the normalized heat load, is that this indicator characterizes not only the actual technical condition of the boiler unit, but also the efficiency of its regulation, taking into account changes outside air temperature