A comprehensive evaluation of zero energy buildings in cold regions: Actual performance and key technologies of cases from China, the US, and the European Union
Evaluation of actual zero energy buildings (ZEBs) performance and identification of its regional characteristics are of great significance for similar future projects. Based on more than 400 cases in cold regions, this study compared the post-evaluation and drivers of ZEBs from China, the US and the European Union (EU). Results found that ZEB definition, energy drivers, standard, regional policies, technology adoption and their adoption ratio determine the energy performance of cases. Not all EU and China cases reach the net-zero energy target; however, most ZEBs in the US do. ZEBs in cold regions adopted multiple technologies to achieve high energy-efficiency. The adoption ratio of passive technologies is higher than that of active technologies, especially in China. The active technologies in cold regions are mainly seen in the application of advanced HVAC systems. Such application of renewable technologies exhibits strong regional characteristics; for example, the EU’s carbon emission reduction policies promoted the use of biomass-based technologies. The analysis also found that energy policies greatly enhance the development of ZEBs. Overall, achieving zero energy is a process, not an endpoint and many projects need further refinement after occupancy.