A comparison of building energy codes and policies in the USA, Germany, and China: progress toward the net-zero building goal in three countries

In recent years, numerous countries and organizations have presented a large number of initiatives and policies to promote the net-zero energy building movement. Although several research efforts have been conducted to set up a consistent and holistic framework of net-zero building standards, the differences in policies and codes related to net-zero buildings and their impacts are not yet fully understood. The aim of this study is to investigate how rapidly the building stock can be transformed into net-zero energy buildings (NZEs). The focus is not technical or based on economic constraints but instead on the potential impact of energy efficiency policies. In response, this paper first presents an overview of the current status of codes and policies related to net-zero building development worldwide. Second, this paper compares and explains the major differences in building energy codes among regions; three countries are used as examples to demonstrate the different approaches. The three countries, which are located on three different continents, are the USA, Germany, and China. Lastly, three prototype buildings are modeled—with similar climate zone classifications as the above-mentioned three countries—based on each country's respective building energy codes. The prototypes are analyzed against a baseline, with and without the impact of building codes and policies. The preliminary results indicate that, currently, China has few stringent building code requirements; however, due to the wider acceptable indoor thermal environmental range, China has higher potential than the USA to achieve the net-zero goal. Additionally, policies in the building sector have had a substantial positive impact on the reduction of energy and carbon emissions in China. In comparison, Germany has slightly higher potential to achieve the net-zero goal than the other two countries, whereas the USA, without a positive energy policy, will underperform in the near future, compared to most countries worldwide. Graphical abstract:

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