© 2021 Elsevier LtdThe influence of a sunspace and a sunspace including PCM louvers on the heating energy consumption was investigated considering a typical rural residence in a severe cold region of China. The analyses were carried out for four different indoor design temperatures, (14, 16, 18 and 20 °C) throughout seven months, from October to next year April. The results show that compared with the original rural residence, the monthly and total energy savings can be respectively attained up to 439 kWh (20.40%) and 1992 kWh (22.73%) when the building is attached with a sunspace at the indoor design temperature of 18 °C. Additionally, the sunspace with PCM louver integration can achieve an extra energy saving of 5.27% throughout the heating period for the same indoor design temperature, compared with the sunspace without PCM louvers. However, when latent heat of PCM is not fully utilized at low indoor design temperatures, PCM louvers may increase the heating energy consumption compared to the sunspace without PCM louvers. It is concluded from the outcomes of the study that the sunspace utilization, especially when integrated with PCM louvers with a reasonable melting point, can significantly contribute to the heating energy saving in buildings in severe cold regions.