Document Type



Available under a Creative Commons Attribution Non-Commercial Share Alike 4.0 International Licence


Architecture engineering, Energy and fuels

Publication Details

A dissertation submitted to the Technological University of Dublin in part fulfilment of the requirements for award of Masters (MSc) in Building Performance (Energy Efficiency Design), January 2023.


The use of energy asset ratings in the construction industry has been criticized in literature and in practice due to its apparent inaccuracies when compared to measured energy usage. In the Irish context the Dwelling Energy Assessment Procedure (DEAP), the asset rating tool has been the topic of many research papers of late with authors citing that in almost all cases the model is underestimating the energy usage of A rated dwellings. This point is of major concern due to A rated Building Energy Rating (BER) certificates now being minimum compliance with the building regulations for new build dwellings. The discrepancy between reality and the energy usage predicted by DEAP is known as the energy performance gap, understanding of the phenomena that impact this gap is limited in research. This dissertation attempts to investigate one of these phenomena which is to quantify the impact that varying occupancy behaviors have on the performance gap. DEAP assumes occupants in all dwellings across the country behave in the exact same way in order to maintain its status as an asset rating tool. Using ethnographic monitoring and occupant interview as a method, the results of this research show that DEAP was underestimating behaviors in areas of Heating, Ventilation and Domestic Hot Water (DHW) but there was significant variation in behaviors between occupants. Results of this interview where then modelled in a dynamic simulation software which had shown that these variations in behavior accounted for 8.5%-25% of the performance gap, the dwelling indicating the greatest performance gap had shown the biggest impact due to varying behaviors. These results highlight the importance of further investigation into not only occupancy behavior but, the additional phenomena which impact the performance gap to better understand how the accuracy of asset rating tools can be improved.