Internationally, buildings are a major contributor to carbon emissions. Despite significant advances in the technology and construction of energy-efficient buildings, in many cases a performance gap between designed and actual performance exists. While much research has investigated the drivers of the building energy performance gap – both static and transient– there has been considerably less research into the total performance gap, defined here as performance gaps in building energy use, occupant satisfaction and Indoor Environmental Quality parameters such as thermal comfort and air quality which may impact on occupant health and wellbeing. This paper presents a meta-analysis of building performance data from buildings in the UK and China – selected due to their contrasting development environments – which illustrate the presence of and complexities of evaluating total performance gaps in both countries. The data demonstrate the need for (1) high end-use, spatial granularity and temporal resolution data for both energy and Indoor Environmental Quality, and (2) developing methodologies that allow meaningful comparisons between buildings internationally to facilitate learning from successful building design, construction methodologies and policy environments internationally. Using performance data from a UK building, a potential forward path is illustrated with the objective of developing a framework to evaluate total building performance. Practical application: While much research has examined building energy performance gaps, Indoor Environmental Quality and occupant satisfaction gaps are rarely included despite their relationship to energy. We use a meta-analysis of energy, indoor environmental quality, and occupant satisfaction data from buildings in the UK and China to illustrating the presence of and complexities of evaluating total performance gaps for buildings in the two countries, and the need for high resolution dynamic buildings data and novel methodologies for comparison between buildings across different contexts. Illustrative case studies are used to demonstrate potential future directions for evaluating ‘total’ building performance.
Synthesis method: Datasets of building performance from the UK (schools) and China (offices).
Conclusions: This paper has presented the results of an ana- lysis of sets of monitored building energy, IEQ performance, and occupant satisfaction data from China and the UK, illustrating total build- ing performance gaps in both countries. Analyses are presented at different granularities and temporal resolutions, and a case study pre- sented to demonstrate how concurrent energy and IEQ data are necessary to identify the root causes of building underperformance in a holistic manner. By taking a ‘total’ approach to building performance, the inter-relation between building energy and IEQ performance may be accounted for, while occupant surveys provide important subjective balance to the quantitative building data. By developing frameworks for dynamic benchmarking of total building performance, it will be possible to compare performance between two contrasting locations such as China and the UK and investigate the influence of the wider system, including dominant construction types, building regulations and government policy.
Screening criteria: In both countries, existing data have been collected using different methodologies, for buildings with different functions, and powered by different energy sources. Therefore, the intention of the paper is not to make comparisons between buildings in the two countries, but to use cur- rently available data to provide insight into the total performance gap in buildings in each coun- try, methodological differences in data collection and analysis, and to explore the data require- ments to assess total building performance. For the purposes of this paper, all buildings built to high energy-efficiency standards will be henceforth referred to as ‘energy-efficient’.
Search source: For the UK, this paper refers to datasets describing top-down energy performance of schools, collected via the UK’s Display Energy Certificate (DEC) scheme, a mandatory scheme implemented in the UK since 2008 under EPBD, and bottom-up energy and IEQ data collected in follow-up studies. Three UK datasets were ana- lysed, including: (1) energy use in conventional secondary schools, acquired through DEC; (2) energy use in secondary schools that were rebuilt, remodelled or refurbished in the past decade under the UK government’s the Building Schools for the Future programme (BSF),32 also through DEC and (3) monitored bottom-up energy and IEQ data for several BSF schools obtained through the BPE programme. Existing data for Chinese buildings were for office buildings rather than schools, and includes three datasets: (1) conventional office buildings portraying the energy use of offices constructed before the inception of new energy efficiency regulations; (2) energy use of 31 office buildings that obtained green building certification in three different climate zones (15 cases in cold zone (north of the Yantze River), 10 cases in hot summer-cold winter zone and 6 cases in hot summer-warm winter zone) and (3) moni- tored IEQ and questionnaire survey data for energy efficient buildings obtained through the Building Thermal Environment programme.
Search keywords: use of building datasets, not literature search
Funding source: The Total Performance of Low Carbon Buildings in China and the UK is funded by the Engineering and Physical Sciences Research Council (EPSRC) grant (EP/N009703/1) and the National Natural Science Foundation of China (NSFC) grant (51561135001).