Reversing the trend of miniaturization of household size would reduce residential energy demands and improve the well-being of the older and younger generations

With urbanization and income growth, residential energy consumption is becoming an increasingly important part of total energy consumption in China and elsewhere in the world. In the United States, for instance, household vehicles account for 68 percent of all energy consumed by road vehicles; in the Republic of Korea, the household sector is responsible for about 52 percent of national energy consumption. Air pollution, both indoors and outdoors, is closely related to household energy consumption.

The total population size of China in 2022 was reduced by 850,000 persons as compared with 2021 and it will continue to decrease with accelerating speed in the coming years. Does the declining size of the population imply that residential energy demands will decrease? No. Compared with population growth, changes in numbers, sizes and structures of households are much more important in determinations of residential energy demands. This is because residential energy commodities such as home-based electricity usage, gas, cooking, space heating or cooling, water and private vehicles are purchased and consumed by households rather than individuals. Higher divorce rates, more migration and the reduction in co-residence between aged parents and adult children contribute to smaller household size, and quickly increasing the numbers of households in China and other countries. Consequently, if energy-use forecasting is based on population growth, which became negative in 2022 in China and has slowed greatly and will become negative soon in many other countries, it would seriously underestimate future residential energy demands and mislead policymakers.

The trend of miniaturization of household sizes not only increases the amount of residential energy demands, but also consequently leads to higher residential energy demands per capita, because smaller households mean fewer people sharing their house, appliances, and vehicles and a decrease in the efficiency of energy use. The average number of persons per household in China in 2020 shrank by 15.5 percent compared to that in 2010 and 23.8 percent to that in 2000. The proportion of one-person households in China in 2020 was 25.4 percent, which was 1.75 times as large as that in 2010. On the other hand, the proportion of three-generation households in China has been quickly declining, from 19 percent in 2000 to 13.8 percent in 2020. Obviously, China is facing a serious energy challenge from the miniaturization of household sizes, which substantially increases residential energy demands and worsens the quality of the environment.

To reverse the trend of miniaturization of household sizes, we propose to adopt policies to promote co-residence between older parents and children, and support rural-to-urban family migrations or family reunions after young migrants are settled in urban areas. Similar to what Singapore successfully did, we propose China to offer financial subsidies for co-residence between older parents and adult children, which will not only reduce residential energy demands and improve the quality of the environment, but also will be beneficial for the health and well-being of both older parents and children. The empirical analysis of Chinese Longitudinal Healthy Longevity Survey data shows that compared with senior citizens who do not live with their children (empty-nesting senior citizens), the cognitive function, self-rated health, and life satisfaction of the senior citizens who co-reside with their children were significantly better by 40 percent, 32.4 percent, and 54.8 percent, respectively. This is because the frequent interactions between children and old parents can effectively delay the decline of old adults' cognitive function, avoid the anxiety and depression caused by loneliness, and significantly improve their mental and physical health. Scholars from other countries also had similar findings among the senior citizens in Finland, Italy and the Netherlands. The data analyses of CLHLS also found that the cash expenditures per person for home care of the senior citizens living with their children were 40.4 percent fewer than that for the empty-nesting senior citizens. On the other hand, compared with residents whose old parents are far away, the housework time spent by women who co-resided with their older parents was fewer by 10 hours per week, the labor force participation rate was higher by 23.1 percent, and the proportion of self-rated good health was higher by 19.8 percent. Obviously, the living arrangements of co-residence living between old parents and their children not only improve the health of senior citizens but also promote the employment and improve the health of children, because of old parents' assistance in housework and care for grandchildren.

In conclusion, reversing the trend of miniaturization of household sizes and promoting co-residence between old parents and children are essential to reducing residential energy demands and improving environment quality, health and well-being of both old and young generations in China and elsewhere, and it is one of the crucial steps toward a sustainable development future.

The author is a professor at the National School of Development of Peking University and a professor at the Centre for Study of Aging and Human Development and Geriatrics Division at the School of Medicine of Duke University. The author contributed this article to China Watch, a think tank powered by China Daily. The views do not necessarily reflect those of China Daily.

Contact the editor at editor@chinawatch.cn.