China is the world’s leading emitter of greenhouse gases and consumer of coal, but it is optimistic to peak CO 2 emissions and lower the carbon intensity of gross domestic product by 60% to 65% below 2005 levels by 2030. However, the country has grand urbanization plans—by 2030, 60% of the country’s population, 880 million people, will live in urban areas. Indoor thermal control of residential buildings consumes large quantities of energy and is responsible for significant CO 2 emissions. This is especially true in severe cold cities because of the large contrast between outdoor and indoor temperatures. Existing studies on residential retrofits examine the effects of implementing only one green retrofit practice at a time primarily for mid- and high-rise buildings.
In this work, we conducted a series of commonly-examined retrofit scenarios to identify the most effective combination of strategies that can reduce the heating demand of an existing single-family house in Harbin, the representative city of China’s severe cold region. This study was conducted in DesignBuilder, a modeling and simulation tool used to analyze a building’s energy performance and total equivalent CO 2. Life-cycle analyses were conducted for the base model and fifteen retrofit scenarios. The results show that a combination of envelope retrofits—specifically, insulation of the walls, roof, floors, and windows—lowered the house’s heating demand by 27.04%, thereby reducing overall energy consumption by 23.92%. The retrofit practices also significantly reduced the structure’s total equivalent CO 2 by 72.77%.
Authorities in Harbin may use the results of this study to subsidize effective retrofitting practices of single-family dwellings. This may help the country reach its climate goals by 2030. Leaders of severe cold regions in other parts of the world—including several states in the U.S.—may be inclined to follow China’s lead to collectively improve environmental, economic, and human health.