Assessment of HVAC generation and emission performance methods in the context of zero-emission buildings in Italy

The revised Energy Performance of Buildings Directive (EPBD) establishes a clear trajectory toward a decarbonised building stock, in which the refurbishment and delivery of zero-emission buildings play a central role. A key challenge in this transition lies in selecting the appropriate methods for assessing the building energy performance, balancing the need for accuracy with the practicality of simplified approaches. This work analyses a representative Italian building, first in its current state and then as refurbished to comply with the zero-emission building requirements defined in the Italian context. Starting from the mandatory national monthly calculation procedures, the analysis is extended to enhanced hourly simplified methods and detailed simulations for assessing the performance of technical building systems. The results highlight methodological differences among these approaches and quantify the impact of varying assumptions on system efficiency and on primary energy use. Particular attention is given to verifying whether a building deemed compliant under the national monthly method, still meets zero-emission energy-efficiency targets when assessed through more detailed procedures. Results provide insight into the robustness of current compliance procedures and support a more consistent implementation of EPBD requirements within the national practice.