S2 S1 Residential airconditioning in China Energy and environmental impacts associated with the building sector in China are significant, representing nearly 16% of total global final energy consumption in buildings 1. In 2016, Chinese building sector consumed 899 million ton of coal equivalent (Mtce), accounting for 20.6% of Chinese annual energy consumption around all sectors 2. Energy demand for space cooling in Chinese building sector is rising rapidly, placing strains on the electricity system and contributing to local air pollution and carbon dioxide (CO2) emissions. The energy consumption for space cooling increased by a factor of 5.4 from 2001 to 2011 3. In addition, in 2018, under the background of consumption upgrade and industrial structure upgrade in China, the retail volume of air conditioner (AC) market was 57 million units, an increase of 1.6% yearon-year. The total production number, export volume, domestic retail volume of Chinese room AC market from 2003 to 2017 is shown in Figure S1. The annual sales volume of ACs have grown steadily, from 20 million in 2003 to 88 million in 2017, an increase by more than four times.