Since more than two-thirds of the United Kingdom housing stock in 2050 will comprise houses that have already been built, the need for a focus of policy on the already-built private housing stock is apparent. This study examines the impact that subsidy can make in bolstering the performance of the Energy Performance Certificate by reducing carbon emissions in the residential sector. The results of a survey of new homeowners' uptake of nine commonly installed energy saving measures in response to subsidy are examined. A cost-benefit analysis is performed using the recently introduced concept of the Shadow Price of Carbon and a model is presented which allows the carbon savings for any level of subsidy to be calculated. The model suggests that subsidisation of the installation of hot water tank insulation, draught proofing measures, loft insulation and cavity wall insulation may be cost-effective, but that the subsidisation of others, most notably interior solid wall insulation, are unlikely to significantly bolster carbon savings. (C) 2009 Elsevier Ltd. All rights reserved.