Official projections for the UK domestic sector indicate that carbon emissions from this sector are expected to fall by some 5 Mt C between 1990 and 2000. It is known that an important factor in this change is the transformation that has been in progress within the electricity supply industry (ESI), specifically the significant move away from coal and towards greatly increased use of gas-fired generation. It is commonly simply assumed that the ESI must account for the majority of the carbon saving. However, as this paper will demonstrate, a rigorous analysis can be undertaken to identify the true components of carbon emission changes. The paper shows that the changes that occur are the result of several factors that act to increase emissions together with factors that act to reduce emissions. The results show that the saving of about 5 Mt C is actually explained by increases in emission of 3.6, 5.2 and 3.8 Mt C (due to increased numbers of households, improved levels of service, and changes to external temperatures, respectively) together with reductions in emissions of 4.1, 4.3, 8.5 and 1.0 Mt C (due to improved insulation, improved efficiency, the ESI, and other carbon factor changes, respectively). Clearly, these figures indicate that carbon emissions would have increased in the absence of the ESI changes. Equally, however, emissions would have risen in the absence of improvements to energy efficiency in the home. It is the combination of these factors that leads to the net reduction.