Addressing low heat pump heating system sales in the UK

The replacement of existing fossil fuel boilers with heat pumps is seen as a key measure in the decarbonisation of heating systems and addressing climate change. This policy however, is currently failing in many Western European states, particularly in the UK. The many reasons for this situation are examined. However, the age of UK housing stock and particularly the high number of dwellings built prior to the introduction of building insulation regulations in 1980, are key. To maintain the running cost of air source heat pumps competitive with those of the gas boilers they generally replace the heat pump lift must be limited on average to 50K, during the heating season. This in turn limits the water temperature generated to typically 55°C compared with 75°C previously with boilers. Hence the need for major insulation upgrading measures. In this article a transition scheme is proposed which allows a dual boiler/heat pump system, while building insulation levels are being raised. This allows the high cost of building fabric upgrading to be spread over a longer period, while also decoupling the cost of fabric upgrading from that of the heat pump installation itself, thus addressing a key reason for low heat pump sales. The technical operation of the dual system is analysed and the operating modes and transition temperatures are considered in detail. More extensive independent design guidance and the use of pilot schemes and case studies is called for, as a means of supporting the proposal.