Do energy subsidies affect the indoor temperature and heating energy consumption in low-income households?

•The effect of an energy subsidy on indoor temperature and heating energy use was analyzed.•The average indoor temperature of low-income households was approximately 23.94 °C.•The indoor temperature of households receiving energy vouchers was approximately 2.06 °C greater than those without energy vouchers.•An energy voucher can increase annual heating energy consumption by approximately 26.6–59.9%. As social interest in energy welfare increases, support programs and policies for fuel poverty are steadily being implemented. Energy subsidies play a significant role in improving the indoor thermal conditions affected by fuel poverty. However, various measures to reduce green-house gas emissions in the building sector are being applied. As a result, a balance between energy welfare and energy saving policies is required. This study aims to analyze the effect of an energy subsidy on improving the indoor temperature and heating energy consumption in low-income dwellings. Long-term and detailed measurements and surveys were conducted for 16 low-income households in an apartment complex in Korea (semi-cold climate). The indoor temperature and heating energy use with/without energy voucher were analyzed. In addition, the annual heating energy consumptions of all 1460 households in the same apartment complex were analyzed. The results showed that the indoor average temperature of the households receiving the energy subsidy was 24.68 °C, and the households without the energy subsidy were 22.62 °C. In addition, the indoor minimum temperature of the households receiving the energy subsidy was about 1.5 °C higher. The annual heating energy use increased by 59.9% for the older building and 26.6% for the newer building compared with those who did not receive energy subsidies. Energy vouchers have a strong influence on the indoor thermal condition and heating energy consumption of low-income dwellings. The energy subsidy policy for the low-income households needs to be re-examined in terms of energy savings and energy welfare.