Assessing the energyperformance of existing buildings based on measurement data. Case study

Abstract

Energy certification for existing buildings and selecting the most appropriate measures in order to classify these buildings as Near Zero EnergyBuildings (NZEB), and therefore complying with specific regulation requirements, implies accessible models and methodologies capable of accurately reflecting the actual energy behavior of buildings and to ensure the optimal quality.Methods based on real data processing, resulting from the monitoring of indoor / outdoor environmental parameters and energy consumption over time, provide results comparable with real scenarios as well as the possibility of validating models and methodologies complying with existing regulations.The method of total heat loss / energy signature, based on the linearity relationship between energy consumption and environmental parameters, is widely used due to its simplicity of application. This method has been used to assess the energy performance for a single-family dwelling designed with a high level of energy efficiency. Results of the analysis revealed an appropriate level of thermal insulation characteristic to the building, reflected in low energy consumption for heating, but also a relatively low thermal inertia, which negatively impacts the energy performance. Comparison between the energy consumption/annual energy demandsfor heating, determined through various methods, recommends the regression approach as a useful tool for validating the various methods used when estimating the energy performance of existing buildings.