The UK housing stock is old and thermally inefficient; one study found that homes in the UK “perform the worst in terms of thermal performance … compared to foreign counterparts” (Guertler et al., 2013, p. 10). Meeting the net-zero target by 2050 requires the elimination of fossil fuels from space/water heating, coupled with improved domestic energy efficiency. Heat pumps will be a key technology for improving the housing stock; they rely on (increasingly low-carbon) electricity and have a greater energy efficiency than natural gas boilers (HM Government, 2021; p.78). We analyse the quantity and distribution of existing heat pump installations to September 2021, looking at how current trends match government ambitions to reach 600,000 installations per year by 2028.
Current Heat Pump Adoption
William Forshaw completed an analysis of the state of heat pump adoption in his final year dissertation in the School of Construction Management and Engineering. He used EPC data for local authorities in England and Wales, which capture all heat pumps installed in new houses, houses marketed for sale, rental houses, and those where EPCs were required to gain access to grants. A summary of adoption from this data source relative to the number of households is provided below.
Figure 1: Map of heat pump uptake in UK local authorities (fraction of total households, using Jenks breaks)
While it is clear that adoption is relatively limited at present (the upper limit of adoption is just over 3% of a local authority’s building stock), one is able to explore the disparities in adoption to date. First, and unsurprisingly, air-source heat pumps are the dominant share of total heat pump adoption recorded (85%). Second, new dwellings made up 60% of households that recorded having a heat pump, with rentals only contributing 11%. Third, detached and semi-detached houses made up 66% of the total number of households with heap pumps installed. Mid-terrace houses only contributed 13%. Flats and maisonettes only represented 8% of households with heat pumps. Considering the latter two statistics, the question of access by lower-income households begins to come evident.
William went on to examine heat pump uptake vs index of multiple deprivation (IMD); this metric uses Office of National Statistics data to provide an indication of areas where lower levels income, employment, education, and other indices of deprivation are prevalent. He found that as local authority IMDs rose, the share of heat pumps in households dropped (Pearson correlation coefficient of -0.36).
Taken with their limited uptake in flats and rentals, this demonstrates the degree to which these lower income households have been excluded from early adoption of this low-carbon heating option. While this is consistent with other new technologies, it does underscore the need for action given this particularly important challenge of dramatically accelerating adoption. Otherwise, these households will be vulnerable if fossil fuels costs continue to rise (due to geopolitical reasons or carbon pricing). As a result, many calling are calling for incentives to encourage adoption within low income households.