Quantifying Building Energy Performance Gap Using a Multi-indicator Framework

Abstract

<p>The energy performance gap (EPG) refers to the discrepancy between predicted energy performance and actual energy performance in buildings. Quantifying the EPG is important for achieving an accurate understanding of building energy performance. Although previous studies have examined the EPG, there lacks a comprehensive method for its quantification. This paper aims to develop a multi-indicator framework to quantify the EPG for achieving a better understanding of the energy performance of buildings. The developed framework provides indicators from three perspectives. First, the EPG of a whole building is quantified by comparing annual and monthly simulated and measured energy consumption. Second, the dynamic of the EPG, referring to how the EPG changes over time, is quantified by analysing its variations using hourly energy data. Third, the hidden gap, referring to the hidden EPG that is neutralised by positive gap and negative gap at building energy service level, is quantified by unfolding the EPG at building energy service level. The developed framework was demonstrated using a case study with a real-life high-rise office building in Hong Kong. The results show that the annual EPG of the case building was + 4%, while the monthly EPG varied widely from − 11% to + 35%. There was a considerable variation in hourly EPG, and the variation was wider in summer than in winter. The annual hidden gap of the EPG was 7 times that of the annual EPG. The proposed multi-indicator framework contributes a multifaceted method for quantifying the EPG. The findings should help clients, designers, contractors, operators, researchers and policymakers to better understand the EPG in buildings and facilitate further strategies for closing the gap.</p>