Analysis and benchmarking of carbon emissions of commercial buildings

Carbon emission, a holistic environmental performance indicator that reflects the level to which resources are used for buildings, has not been studied as widely as energy use. Commercial buildings, especially the existing ones, utilize substantial operating resources, but empirical carbon studies on such buildings, as compared with the counterparts on new buildings, are limited. To contribute knowledge about factors that affect the carbon emission level of existing commercial buildings and establish meticulous benchmarks for gauging and comparing their environmental performance, a study was conducted on 32 buildings in Hong Kong. Through face-to-face meetings with the buildings’ representatives, reliable monthly data over a period of six years were collected. Analyzing the data revealed that carbon emission level is more significantly correlated with total floor area than age or common floor area of the buildings. Benchmarking charts, constructed based on the buildings’ normalized carbon emission levels, enable comparisons to be made between the environmental performances of peer buildings in different ranges of age and scale. The finding that small buildings generally produced more carbon emissions per unit floor area than the large ones is important information for policy-makers and facility managers in prioritizing environmental conversation measures for implementation in existing buildings.