Impact of Construction Deviations on Energy Performance Certification: A Case Study of a Residential Building in Slovakia

Energy performance certification of buildings is a key instrument for assessing energy efficiency within the framework of the Energy Performance of Buildings Directive (EPBD). In practice, significant discrepancies are often observed between the predicted and actual energy performance of buildings. One of the main causes of this discrepancy is non-compliance with technological procedures during construction. This paper analyses the energy and economic consequences of such deviations through a case study of a newly constructed residential building in northern Slovakia that was originally certified in the A0 energy class. The research methodology included in situ inspection of the building, thermographic measurements, destructive probes of the building envelope, analysis of project documentation, and recalculation of energy performance using measured building parameters. The results revealed significant deficiencies in the thermal insulation of the building envelope, roof construction, and window airtightness. After recalculation based on measured parameters, the building’s energy classification deteriorated from A0 to B. The total energy demand increased by 46%, while primary energy demand increased by 141%. The results demonstrate that construction deviations can significantly affect the reliability of energy performance certification. The study highlights the importance of verifying the actual condition of buildings during construction to ensure the reliability of EPC assessments.