There are currently about 29 million homes in the UK, of which 19 million are below EPC C. Of these, an estimated 8 million are solid wall properties and an estimated 1 million are within conservation areas.
Table 1: EPC rating by tenure, England.
Our 6CB balanced net zero pathway includes 3.1m cavity walls insulated, along with 11m lofts and 3.4m solid walls (with a priority on fuel poor households, which make up 1.2m of these), along with floor insulation, heating controls and other measures.
In total, 15m households receive one of the main insulation measures (loft/wall/floor) and a further 8 million benefit from draught-proofing. All fuel poor homes receive a high efficiency upgrade.
We assume all lofts and practicable cavities can be insulated, but not all solid wall properties are insulated. This reflects the high costs of solid wall insulation. Our assessment also takes in to account lower estimate savings based on the NEED dataset, which uses metered energy consumption to provide estimates of how measures perform in-use.
There are currently around 18m properties which are owner-occupied, of which about 1.5m are fuel poor, leaving 16.5m ‘able-to-pay’ properties not currently covered by proposed standards outside of Scotland.
Around 47% of owner-occupied homes are currently covered by a mortgage.
Figure 1 Household investment and operating
costs for existing homes, Balanced Pathway
Sources: Element Energy for the CCC (2020) Development of trajectories for residential heat decarbonisation to inform the sixth carbon budget; CCC analysis.
Energy efficiency – supplier obligations were effective in the UK, but German KfW bank shows how Green Deal could have worked, as does PACE in the US. For more detail, see the three supporting What Works studies published alongside our 2016 report, Next Steps for UK Heat Policy.
 CCC calculations, based on: (a) MHCLG (2020) 'Table 109: by tenure and region, from 1991', Live tables on dwelling stock. Ministry of Housing, Communities & Local Government; (b) Scottish Government (2018) Housing statistics: Stock by tenure. Scottish Government; (c) Stats Wales (2020) Dwelling stock estimates by year and tenure. Welsh Government; (d) Department for Communities (2019) 'Northern Ireland Housing Statistics 2018-19 Section 1 Tables - Supply', Northern Ireland Housing Statistics 2018-19. Northern Ireland Government.
 CCC calculations, based on: (a) MHCLG (2019) 'Annex Table 1.2: Energy efficiency rating bands, by tenure, 2008, 2013 and 2018', English Housing Survey: Energy efficiency, 2018-19. Ministry of Housing, Communities and Local Government; (b) Scottish Government (2020) Scottish House Condition Survey: 2018 Key Findings. Scottish Government; (c) Statistics for Wales (2019) Statistical Bulletin - Welsh Housing Conditions Survey 2017-18: Energy Efficiency of Dwellings. Welsh Government.
 Based on: MHCLG (2019) 'Annex Table 1.2: Energy efficiency rating bands, by tenure, 2008, 2013 and 2018', English Housing Survey: Energy efficiency, 2018-19. Ministry of Housing, Communities and Local Government.
 Calculated from percentage for England, in: BEIS (2020) 'Table 18: Fuel poverty detailed tables 2020', Fuel poverty statistics report for 2020. Department for Business, Energy & Industrial Strategy.
 MHCLG (2019) English Housing Survey: Home Ownership, 2017-18. Ministry of Housing, Communities & Local Government.