## 4 Factors Affecting HErC
### Household Characteristics  
With the acceleration of urbanization in China, household sizes have gradually decreased, and the aging population has become increasingly prominent. The number of small and single-person households has been rising, while the educational levels of household members have also seen significant improvements. These changes collectively shape the new characteristics of urban households. Factors such as household size, structure, and education level, as key determinants of energy and resource use efficiency, jointly influence HErC.  
Different household structures result in varying HErC [27]. [PERSON] et al. found that in urban areas, childless households and households consisting of spouses plus parents have the lowest and highest impacts on household energy consumption, respectively [28]. Some studies have further validated this by analyzing the age structure of household members. [PERSON] et al. demonstrated that each additional laborer in a household can reduce per capita energy consumption by 43.8 kg of standard coal per year [29]. Similarly, [PERSON], [PERSON] and [PERSON] showed that the retirement of household members increases household electricity consumption by 20.0-32.1% [30]. These studies indicate that the diversity of urban household structures leads to significant differences in energy consumption patterns and carbon emission levels. Consequently, policymakers need to consider this diversity when developing energy-saving and emission reduction policies.  
The impact of household size on urban HErC cannot be overlooked. [PERSON] et al. observed that as the number of household members decreases, primarily due to the preva  
Figure 5: Frequency of influencing factors.  
lence of nuclear families, per capita energy consumption increases [6]. In another study, [PERSON] et al. focused solely on residential electricity use and concluded that an increasing proportion of single-person households tends to curb the growth of electricity consumption [31]. [PERSON] et al. provided a more comprehensive perspective by classifying urban households based on size and income [32]. Their findings suggest that a shift toward smaller households may lead middle-income families to adopt carbon-intensive energy lifestyles, whereas high-income households are more likely to embrace energy-efficient and greener consumption patterns. These studies have established the significant impact of changes in household size on HErC. However, divergent views indicate that the underlying mechanisms require further investigation.  
The influence of educational attainment on HErC is significant and multifaceted. On one hand, households with higher education levels typically exhibit stronger environmental awareness and are more likely to adopt energy-saving and emission-reduction measures [28]. They are also more receptive to energy transitions and the use of clean energy [33; 34]. [PERSON] et al. approached the issue from the perspective of carbon capability and found that residents with higher education perform better in terms of carbon knowledge, motivation, behavior, and management capacity [35]. On the other hand, higher education is often associated with higher household income, which may lead to more lenient energy consumption practices and consequently increased HErC. [PERSON] and [PERSON] confirmed this view in a study of elderly residents [30], and [PERSON] et al. found a significant positive correlation between educational attainment, household income, and commuting-related carbon emissions, noting that households with higher education levels tend to favor high-carbon private transportation modes [36]. The complex impact of educational attainment on HErC suggests that improving education and disseminating environmental knowledge are crucial for fostering lower-carbon lifestyles and preventing excessive energy use.