Building insulation statistics show uneven coverage across England and Great Britain. In 2024, insulation measures ranged from cavity-wall coverage among homes with that wall type to much lower solid-wall coverage, while age, tenure, dwelling type and region shaped the pattern.
Key Building Insulation Statistics
The most useful headline figures are:
- 54% of dwellings in England had cavity or solid wall insulation in 2024, according to the English Housing Survey estimate.
- 15.2 million Great Britain homes had cavity wall insulation at 31 December 2024, equal to 71% of homes with a cavity wall.
- 876,000 Great Britain homes had solid wall insulation at 31 December 2024, equal to 10% of homes with solid walls.
- 17.5 million Great Britain homes had loft insulation at 31 December 2024, equal to 67% of homes with a loft.
- 42% of English dwellings had at least 200mm of loft insulation in 2024.
- About 2.7 million English households lived in homes with less than 100mm of loft insulation in 2024-25.
- Housing-association solid-wall dwellings in England reached 37% insulation coverage in 2024, compared with 11% for owner-occupied solid-wall dwellings.
- 46% of English homes built before 1919 had internal insulation in 2024-25.
- External wall insulation covered 7% of English terraced houses in 2024-25, compared with 2% of detached houses.
- Scotland had 81% of cavity-wall homes insulated at the end of 2024, compared with 71% across Great Britain.
- 98% of England-and-Wales dwellings with a very-good wall-insulation rating achieved EPC band C or above up to March 2022.
- The median current energy-efficiency score was 72 for flats and the median potential score was 78 up to March 2022.
- English dwellings built before 1945 cost an average £9,300 to improve to band C or above in 2023-24.
- Average annual CO2 emissions were 5.0 tonnes for English homes built before 1945 in 2023-24.
- About 823,000 English dwellings had serious condensation or mould in 2024.
- Great Britain added about 40,600 homes with solid wall insulation during 2024, a 4.9% increase.
Contents
- Key building insulation statistics
- Housing-stock coverage and insulation adoption
- Loft insulation levels and trends
- Wall insulation by construction type and tenure
- Differences by age, dwelling type and region
- Energy performance, costs and carbon outcomes
- Condensation, retrofit need and programme delivery
Housing-Stock Coverage and Building Insulation Adoption
The English Housing Survey estimated that 54% of dwellings in England had cavity or solid wall insulation in 2024, up from 48% in 2014. The estimate includes assumptions for some post-1995 cavity-wall homes, so it should be read as a housing-stock estimate rather than a direct installation count. English Housing Survey 2024 to 2025: home insulation – fact sheet
Great Britain figures use different denominators for different wall and roof types:
| Measure | Great Britain estimate | Population and period |
|---|---|---|
| Cavity wall insulation | 15.2 million homes; 71% | Homes with cavity walls, 31 December 2024 |
| Solid wall insulation | 876,000 homes; 10% | Homes with solid walls, 31 December 2024 |
| Loft insulation | 17.5 million homes; 67% | Homes with a loft, 31 December 2024 |
The Household Energy Efficiency Statistical Release describes these as DESNZ housing-stock estimates combining retrofit, new-build and administrative or programme evidence. It estimated that cavity-wall insulation increased by about 214,100 Great Britain homes during 2024. Household Energy Efficiency Statistical Release, March 2025
In England, 642,000 dwellings had internal wall insulation and 666,000 had external wall insulation in 2024. Each represented 5% of dwellings with insulated walls, not 5% of all dwellings, so these figures describe subcategories of the insulated-wall stock. English Housing Survey 2024 to 2025: home insulation – fact sheet
Loft Insulation Statistics and Recent Trends
Loft coverage depends heavily on the thickness threshold and denominator. In England, 42% of all dwellings had at least 200mm of loft insulation in 2024, compared with 39% in 2014 and 39% in 2022; the survey notes methodological variation across years and that the all-dwelling denominator includes homes without a loft. Chapter 2: Energy efficiency, English Housing Survey 2024 to 2025
Great Britain added approximately 232,000 homes with at least 125mm of loft insulation during 2024. An estimated 68,800 came through retrofit and 163,200 through new build, so the annual increase is not a retrofit-only measure. Household Energy Efficiency Statistical Release, March 2025
Low-thickness loft insulation remained widespread in England:
- About 2.7 million English households lived in homes with less than 100mm of loft insulation in 2024-25.
- Among those households, about 297,000 had a youngest member under age 5.
- Approximately 444,000 were in relative low income, using the English Housing Survey reporting definition.
- More than 1 million contained someone with a long-term illness or disability.
These figures describe households in homes with lofts and less than 100mm of insulation; they are not estimates for every English household. English Housing Survey 2024 to 2025: home insulation – fact sheet
Wall Insulation Data by Construction Type and Tenure
Solid-wall coverage was much lower than cavity-wall coverage in Great Britain because the relevant wall types have different denominators. In England, the share of all dwellings with solid wall insulation increased from 3% in 2022 to 4% in 2024. Chapter 2: Energy efficiency, English Housing Survey 2024 to 2025
Among English solid-wall dwellings in 2024, tenure differences were pronounced:
| Tenure | Solid-wall dwellings with insulation |
|---|---|
| Housing association | 37% |
| Local authority | 34% |
| Owner occupied | 11% |
| Private rented | 10% |
Housing-association solid-wall coverage rose from 28% in 2023 to 37% in 2024. These percentages use solid-wall dwellings within each tenure as the denominator, not all homes in the tenure. Chapter 2: Energy efficiency, English Housing Survey 2024 to 2025
A separate 2024-25 English Housing Survey subgroup examined homes with less than 100mm of loft insulation and a cavity wall. Insulated versus uninsulated cavity-wall results were 49% versus 15% for local-authority renters, 48% versus 19% for housing-association renters, 35% versus 23% for owner occupiers, and 13% versus 29% for private renters. English Housing Survey 2024 to 2025: home insulation – fact sheet
Building Insulation Differences by Age, Dwelling Type and Region
Older English homes had the highest reported internal insulation coverage. Among homes built before 1919, 46% had internal insulation and 15% had external insulation in 2024-25, while internal insulation ranged from 2% to 6% among post-1919 construction groups and external insulation ranged from 1% to 8% among homes built from 1945 onward. English Housing Survey 2024 to 2025: home insulation – fact sheet
Dwelling form and tenure also mattered:
- External wall insulation covered 7% of English terraced houses, 5% of semi-detached houses and 2% of detached houses in 2024-25.
- Internal insulation was present in about 5% of owner-occupied and private-rented dwellings, versus 2% of social-rented dwellings.
- External insulation covered 10% of social-rented dwellings, compared with 5% of private-rented and 3% of owner-occupied dwellings.
Regional estimates showed 8% internal insulation in England’s South West, compared with 2% to 5% across other regions. External insulation covered 9% of London dwellings, compared with 3% to 5% in almost all other English regions. English Housing Survey 2024 to 2025: home insulation – fact sheet
The Great Britain stock estimates also showed national differences at 31 December 2024:
| Geography | Cavity-wall homes insulated | Homes with loft insulation at least 125mm | Solid-wall homes insulated |
|---|---|---|---|
| Scotland | 81% | 86% | 23% |
| Great Britain | 71% | 67% | 10% |
| Wales | 75% | 65% | Not supplied |
| England | 69% | 65% | Not supplied |
The denominators differ by wall or loft type, and the release’s national estimates include its stated assumptions. Household Energy Efficiency Statistical Release, March 2025
Energy Performance, Costs and Carbon Outcomes
EPC evidence links insulation ratings with energy-performance outcomes, but it does not establish that insulation alone caused the scores. Up to March 2022, 98% of England-and-Wales dwellings with a very-good wall-insulation rating achieved EPC band C or above; the corresponding Wales figure was 97%. Insulation and energy efficiency of housing in England and Wales: 2022
For roof insulation, 69% of English houses and 63% of Welsh houses with a very-good roof-insulation rating achieved EPC band C or above up to March 2022. The source notes that the roof relationship was weaker than the wall relationship. Insulation and energy efficiency of housing in England and Wales: 2022
The same EPC analysis reported a median current score of 72 for flats and a median potential score of 78. The median current-to-potential gap was 4 SAP points for flats and 20 points for terraces, calculated per dwelling before taking the median rather than as a mean savings estimate. Insulation and energy efficiency of housing in England and Wales: 2022
Age cohorts showed a broad energy-performance gradient: homes built in or before 1929 had a median current score of 59, while homes built from 2012 onward had a median potential score of 87. Potential scores assume that all EPC-recommended measures are completed. Insulation and energy efficiency of housing in England and Wales: 2022
The English Housing Survey modelled average costs to reach band C or above in 2023-24:
| Construction period | Average modelled cost per dwelling |
|---|---|
| Before 1945 | £9,300 |
| 1945 to 2012 | £5,100 |
| Post-2012 homes below band C | £2,500 |
These are costs for all recommended improvements, not insulation alone. Average annual CO2 emissions were 5.0 tonnes for homes built before 1945, 3.3 tonnes for homes built from 1945 to 2012 and 2.2 tonnes for post-2012 homes; these are associations across cohorts that also reflect heating systems and other dwelling characteristics. English Housing Survey 2023 to 2024: climate resilient homes – fact sheet
Condensation, Retrofit Need and Programme Delivery
About 823,000 English dwellings had serious condensation or mould in 2024. The English Housing Survey records issues serious enough for its housing-health assessment, so minor problems are excluded. English Housing Survey 2024 to 2025: home insulation – fact sheet
Among households in homes with less than 100mm of loft insulation in 2024-25, about 197,000 had serious condensation in one or more rooms. Within that subgroup, about 34,000 households had uninsulated cavity walls and about 133,000 had uninsulated solid walls. English Housing Survey 2024 to 2025: home insulation – fact sheet
For homes with less than 100mm of loft insulation and uninsulated cavity walls, condensation affected 24% of social renters, 5% of private renters and 3% of owner occupiers in England in 2024-25. The social-renter estimate may be sample-sensitive, and the subgroup should not be generalized to all renters or owners. English Housing Survey 2024 to 2025: home insulation – fact sheet
Retrofit progress in Great Britain during 2024 included about 40,600 more homes with solid wall insulation, a 4.9% increase. The release assumes this increase was retrofit and excludes Scotland Green Homes Cashback measures from the cited progress figures. Household Energy Efficiency Statistical Release, March 2025
Since 2013, the Energy Company Obligation supplied most government-scheme retrofit measures in Great Britain:
- 96% of government-scheme retrofit cavity-wall measures came through the Energy Company Obligation during 2013-2024.
- 92% of government-scheme retrofit loft-insulation measures came through the Energy Company Obligation during 2013-2024.
- 76% of government-scheme retrofit solid-wall measures came through the Energy Company Obligation during 2013-2024.
These shares cover measures funded through government schemes, not every insulation installation. The DESNZ release combines programme and administrative evidence, while the English Housing Survey percentages vary by loft, wall type, tenure, age and region; EPC analysis covers only dwellings with an EPC and uses standardised occupancy and behaviour assumptions.