For the last three decades, there has been a fivefold increase in the number of single-family houses in South Korea. In 2015, 30% of the total households were single-family houses, and the number of single- and two- family houses is projected to account for 68.0% of the total households by 2035. Consequently, the residential energy consumption by single-family houses is very likely to increase in the coming years. In addition, although residential energy consumption per capita is higher for single-family houses in South Korea, corresponding energy-efficiency measures are currently insufficient. As single-family houses, just as non-single-family houses, purchase and use homeappliances and electronic devices, the growing number of single-family houses is likely to lead to their increasing residential energy consumption.
Generally, the larger the family size, the more residential energy is consumed. This report also shows that the residential energy consumption and carbon emission per household were 1.3 times higher in five-family houses than in single-family houses. However, single-family houses’ per capita energy consumption and carbon emission were three times higher than in five-family houses. Per capita water consumption and house-heating by single-family houses also were two times higher than in five-family houses. These findings reflect that, as family size increases, per capita residential energy consumption decreases by the economy of scale.
This report further carries out a scenario-analysis in order to explore and compare patterns of residential energy consumption by household appliances and electronic devices in three types of single-family houses as student, middle-age, and elderly. It shows that the use of energy-efficient appliances could reduce energy consumption by 18.5~25%. In particular, the use of common energy-efficient appliances, such as fridges/freezers and laundry appliances, could result in large energy savings.
However, two common characteristics of single-family households in South Korea are, first they are rented and second they use built-in home appliances. Hence, their use of energy-efficient appliances is not fully determined by themselves, but is largely determined by the owners of the houses. 
In order to promote residential energy-saving in single-family houses in South Korea, both owners and tenants must support it, and institutional strategies such as incentives should be introduced to encourage owners to provide and tenants to use energy-efficient appliances. Even a one-size-fits-all solution to inefficient energy consumption in single-family houses may be insufficient. Instead, age- and lifestyle-specific policies should be instituted to achieve efficient energy consumption in the growing number of single-family households in South Korea.