In this paper, taking Nanchang, China, as an example, we first systematically divided household behaviour into three components: entrance (eight lifestyles), kernel (energy uses and private vehicles) and outlet, which was a concern of few scholars and contained the carbon emissions (CEs) of domestic wastewater treatment and landfills. The CEs of entrance were calculated by consumer lifestyle approach and others by Intergovernmental Panel on Climate Change (IPCC). The results showed all the CEs of entrance, kernel and outlet had increasing trend from 1998 to 2014. They were 172.65 × 104, 22.19 × 104 and 9.18 × 104 t CO2 in 1998 and increased to 283.10 × 104, 78.83 × 104 and 23.03 × 104 t CO2 in 2006 and to 458.43 × 104, 206.82 × 104 and 33.55 × 104 t CO2 in 2014. Their shares were 66%–85%, 11%–30% and 4–6%, respectively. Although the CE shares of wastewater treatment and landfills are currently modest, they will become increasingly greater in the future. Thus, it is significant to construct this new accounting frame, especially for analysing sustainable household consumption behaviour. Finally, some attributes of the new frame are clarified, and related policy implications are put forward.