Imperfections of calculation and information methods of building energy performance certificates
DOI:
https://doi.org/10.17512/INSTAL.2026.08.03Keywords:
energy performance certificate, EP, primary energy, technical requirements, cooling, overheating, biomass, formal optimization, informational value of the certificateAbstract
The annual non-renewable primary energy demand indicator EP performs both a regulatory and an informational function in the Polish system for assessing the energy performance of buildings. It is a criterion for compliance with the technical requirements and the main parameter presented in the energy performance certificate. This accumulation of functions creates methodological tension, because EP describes the building’s burden in terms of non-renewable primary energy, but it does not always inform the user about final energy consumption, operating costs, or thermal comfort. The aim of the article is to demonstrate the imperfections of the current methodology for assessing the energy performance of buildings and to indicate that the proposed amendments to the technical requirements of 9 June 2025, despite tightening some requirements, do not eliminate the problems related to the structure of EP, the assessment of cooling, lighting, and actual operation. In a residential building without a cooling system, the ΔEPC component may be equal to zero, while the built-in lighting component ΔEPL does not affect the result. The article analyses two calculation examples. In the first example, a building with poor thermal performance and EK = 180 kWh/(m²·year), heated with natural gas, obtained EP = 198.0 kWh/(m²·year). After assigning 80% of the energy balance to biomass and 20% to gas, EP decreased to 68.4 kWh/(m²·year). The reduction amounted to 129.6 kWh/(m²·year), i.e. 65.5%, despite no improvement in insulation, windows and doors, airtightness, or final energy demand. In the second example, a building with EP = 70.0 kWh/(m²·year), after the application of a photovoltaic installation, obtained EP = 65.55 kWh/(m²·year), which means a decrease of 4.45 kWh/(m²·year), i.e. 6.4%. This results from the fact that, in residential buildings, the electricity used by household appliances and lighting is not included in the calculations for the energy performance certificate. The results confirm that a low EP value does not necessarily indicate low final energy consumption or high building performance in use. The energy performance certificate should therefore be supplemented with indicators of overheating risk, cooling demand, final energy demand, and the operational scenario.
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Copyright (c) 2026 Łukasz Trzciński, Michał Turski (Autor)
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