Although its per capita carbon emissions are still relatively low, China’s aggregated carbon emissions have grown by nearly 4-fold in the last three decades, and now it is the biggest CO2 emitter in the world. There are many reasons for this emissions growth, and much emphasis has been placed on industrial development, but previous research has estimated that 40% of the growth in Chinese CO2 emissions over the 15 years to 2007 can be attributed to household energy consumption. In this paper, we conduct a decomposition analysis to show that in the period from 1978 to 2008 nearly 60% of the growth in Chinese household emissions can be attributed to the increasing number of households and 40% to increasing emissions per household. We also show that over this period emissions growth in urban households has been six times that of rural households. These results have important implications for policy makers seeking to promote reductions in China’s CO2 emissions, relating for example to family planning and urbanization.