Household Energy Efficiency Statistics, detailed report 2025

This annual report presents detailed statistics on the Energy Company Obligation (ECO), the Green Deal (GD) and other government energy efficiency schemes, as well as insulation levels in Great Britain, up to the end of 2025. This is the eleventh annual release following the user consultation that took place in autumn 2015 on GD, ECO and insulation level statistics. It includes further analysis and geographical breakdowns of ECO measures. It also includes ECO delivery costs, estimated carbon and energy savings from measures installed, the GD supply chain, and estimates of home insulation levels. This release also covers further breakdowns of measures installed under various other government support schemes. These statistics are provisional and are subject to future revisions. For further information or questions about these statistics, email energyefficiency.stats@energysecurity.gov.uk. --- Household Energy Efficiency Statistics Great Britain, data to end-December 2025 Households receiving at least one measure through household energy efficiency schemes, annual to end-2025 Headlines • From 2013 to the end of 2025, 4.9 million household energy efficiency measures were installed in 2.9 million households in Great Britain through various government support schemes. • Around 126,900 households were upgraded across all schemes in 2025. For ECO, this total only includes households upgraded for the first-time. This was a decrease of 6% compared with 2024. 385,000 measures were installed in households in 2025, a decrease of 14% from 2024. • ECO has remained the largest energy efficiency scheme. Measures delivered through ECO accounted for 71% of all measures installed in 2025. During 2025, ECO delivered 271,700 measures. Around 60,500 households received an ECO measure for the first time. This was a decrease of 3% in first-time households and 19% in measures compared to 2024. • In 2025, around 45,700 households were upgraded through GBIS, 14,900 through SHDF, 4,900 through HUG, 370 through WH:SHF and 450 through WH:LG. The WH:SHF and WH:LG figures are likely to be revised upwards in future months. • Of the households treated through LAD, HUG and SHDF initially rated EPC band D or lower, 75% were upgraded to EPC band C or above. About this release The annual report presents collated statistics on government supported energy efficiency schemes in Great Britain (GB) and updated estimates of GB insulation levels. In this release Detail about this publication Overall trends in measures and households Types of measures installed Household characteristics National and regional trends Costs Estimates of home insulation levels in Great Britain Benefits monitoring Technical Information Further Information 2 3 6 10 12 17 18 22 24 25 Scheme Information For information on the schemes please see the associated background note. Data tables The underlying tables are available in Excel format at HEE Statistics. This publication is based on data from the scheme administrators. New data are incorporated in line with the DESNZ statistical revisions policy developed in accordance with the UK Statistics Authority Code of Practice for Statistics. 1 Detail about this publication This publication provides an update to the annual detailed Household Energy Efficiency publication last published in March 2025. It presents information on household energy efficiency schemes to the end of 2025. The schemes included (with abbreviations used in the text) are: • Energy Company Obligation (ECO) • Green Homes Grant Vouchers (GHGV) • Green Deal (GD) Framework • Local Authority Delivery (LAD) • Home Upgrade Grant (HUG) • Social Housing Decarbonisation Fund (SHDF) • Great British Insulation Scheme (GBIS) • Warm Homes: Social Housing Fund (WH:SHF) • Warm Homes: Local Grant (WH:LG) This report focuses on these nine energy efficiency schemes and differences between them. For example, differences in where the households are that have been upgraded by each scheme, or the types of measures installed under each scheme. However, not all schemes are available for each table. For example, because of the small number of measures reported by grant recipients so far and the risk of disclosure, WH:SHF and WH:LG data are not shown in every table. Some Energy Company Obligation (ECO) and Green Deal tables and associated descriptive text have been removed from this publication where this is duplicated in other publications. Other table numbers have remained the same so users can compare with last year’s release easily. The tables that have been removed that were in last year’s publication are: Table 2.1: Estimated carbon and energy savings through ECO and the Green Deal Framework to end March 2022 This table is unchanged since the last annual publication. Table 3.2: ECO measures by property main fuel type, ECO obligation and by year This table is available (quarterly) in the February 2026 Household Energy Efficiency Statistics release Table 3.4: ECO Affordable Warmth measures installed since the introduction of Flexible Eligibility, by administrative area This table is available in the February 2026 Household Energy Efficiency Statistics release Table 6.1: Cumulative number of Green Deal Plans in domestic unique properties, by end of year This table is available in the February 2026 Household Energy Efficiency Statistics release Table 6.2: Number of measures installed using Green Deal Finance, by end of year This table is unchanged since the last annual publication Table 8.1 also presents data for other retrofit schemes that aren’t in the main energy efficiency tables. These are: • Boiler Upgrade Scheme • Feed-in Tariffs • Domestic Renewable Heat Incentive • Renewable Heat Premium Payment All phases and waves for each scheme are included in the tables, unless otherwise stated. More information on all the schemes can be found in the accompanying Methodology Note. 2 Overall trends in measures and households Tables 1.1 to 1.2 The tables show the number of measures installed and the number of households receiving measures under the nine energy efficiency schemes presented. Headlines • From 2013 to 2025, 2.9 million households had measures installed through different government support schemes • There were 4.9 million measures installed in total through those schemes • In 2025, 385,000 measures were installed in 126,900 households. Households upgraded from 2013 to end-December 2025 From January 2013 to the end of December 2025, an estimated 2.9 million households in Great Britain received at least one energy efficiency measure through the nine energy efficiency schemes presented (Table 1.2). As with previous years, totals across schemes include some double counting, as some households receive measures through more than one scheme. The Energy Company Obligation (ECO) upgraded 2.6 million households over this period, reflecting its operational period and scale. Smaller numbers of households were supported through Green Deal schemes, including Green Deal Finance Plans (13,800 households), Cashback (14,700), the Green Deal Home Improvement Fund (35,300) and Green Deal Communities (15,600). Together, these programmes account for a relatively small share of total household upgrades compared with ECO but contributed to delivery during the earlier years of the period shown here. More recent schemes have made an increasing contribution to household delivery since 2020. The Green Homes Grant Local Authority Delivery (LAD) scheme upgraded 58,600 households across Phases 1 to 3 by the end of 2025, while the Home Upgrade Grant (HUG) upgraded 15,800 households, focusing on low-income homes off the gas grid. The Social Housing Decarbonisation Fund (SHDF) has supported 57,200 households through Waves 1, 2.1 and Wave 2.2 delivery, reflecting its role in improving energy efficiency in the social housing sector. The Great British Insulation Scheme (GBIS), launched in 2023, upgraded 92,700 households by the end of December 2025, operating alongside ECO. Households upgraded in 2025 In 2025, around 126,900 households received at least one energy efficiency measure through these schemes. For ECO, this total only includes households upgraded for the first-time. It doesn’t include households upgraded under ECO4 who had previously had a measure installed in an earlier phase of the scheme. The total number of households that had a measure installed fell by 6% between 2024 and 2025, due to lower delivery through SHDF, HUG and ECO. This was partially offset by an increase in households receiving measures under GBIS and the introduction of the Warm Homes schemes. ECO has remained the largest single scheme in 2025, upgrading 60,500 households. These were households that received a measure for the first time under ECO. The number of these first-time households was 3% lower than in 2024, when around 62,200 households received an ECO measure for the first time. The number of households receiving measures through GBIS increased in 2025. Around 45,700 households received measures, an increase of 5% from around 43,600 households in 2024. This growth reflects GBIS moving into full delivery following its launch in spring 2023 and potentially the effect of the GBIS mid-scheme changes. 3 The number of upgraded households in HUG and SHDF fell between 2024 and 2025. In 2025, around 4,900 households were upgraded through HUG, compared with around 6,600 households in 2024. HUG2 ran until end-March 2025. SHDF supported around 14,900 households in 2025, down from around 22,900 households in 2024. The reduction reflects the delivery profile of Waves 1 and 2.1, where installation activity peaked in 2024 before decreasing in 2025. SHDF Wave 1 closed in March 2024. The two Warm Homes schemes contributed a small share of delivery in 2025. WH:SHF reported measures in around 370 households, while WH:LG reported measures in around 450 households during the year. Previous schemes have seen significant upward revisions to early data, and it is expected to be the same for WH:SHF and WH:LG. Number of measures installed 4.9 million measures were installed in these households over 2013 to 2025 through these nine schemes. In terms of measure delivery, ECO accounted for between 71% and 86% of measures installed in each of the last five years (Chart 1). Chart 1: Share of measures installed by scheme, to end-December 2025 (Table 1.1) In 2021, GHGV delivered the second highest number of measures. After the closure of GHGV in 2021, LAD became the second biggest scheme in 2022, accounting for 20% of measures, followed by SHDF at 3%. After the closure of LAD in 2023, ECO made up 75% of measures installed in 2024. In 2025, ECO made up 71% of measures, and the proportion of measures that were from GBIS was 17%, increasing from 1% in 2023 and 12% in 2024. In the last three years, SHDF has accounted for 9% to 11% of measures installed. In 2025, 385,000 measures were installed. This was 14% lower than 2024. This was mostly driven by the decrease in ECO measure delivery of 19% between those two years. Other household retrofit measures Information on households with other household retrofit measures is given in Table 8.1. 4 Boiler Upgrade Scheme The Boiler Upgrade Scheme (BUS) provides upfront grants to support the installation of low‑carbon heating technologies, including air‑source and ground‑source heat pumps. Grant values increased in October 2023 to £7,500 for heat pumps. To the end of December 2025, around 73,100 BUS vouchers had been redeemed and paid. This figure includes a small number of non-domestic properties (less than 0.5%) Feed-in Tariffs (FITs) The Feed-in Tariff scheme supported smalls cale low carbon electricity generation, including solar PV, wind, hydro and anaerobic digestion, before closing to new applicants in March 2019. Most installations were in the domestic sector (96%), although domestic installations accounted for a smaller share of total installed capacity due to their size. Between January 2013 and the end of December 2025, 483,600 domestic installations were confirmed on the Central FIT Register. Domestic Renewable Heat Incentive and Renewable Heat Premium Payment The Domestic Renewable Heat Incentive (RHI) provided tariff payments to households installing eligible renewable heating systems and closed to new applicants in March 2022. By the end of March 2024, around 113,400 domestic installations had been accredited. Prior to the RHI, the Renewable Heat Premium Payment (RHPP) acted as an interim scheme to support uptake of domestic renewable heat, with solar thermal and air source heat pumps accounting for the majority of installations. 5 Types of measures installed Tables 1.3 and 3.1 The number of different types of measures installed for different schemes. Headlines • Across all schemes to the end-December 2025, 53% of measures installed were insulation measures (including window and door measures), while 47% were heating and other non-insulation measures. • To end-December 2025. the most installed measure types were cavity wall insulation and ‘other heating’ measures (the majority of which were heating controls), each accounting for 23% of all measures installed, followed by boiler measures, which made up 19%. • In 2025, the most frequent group of measures installed were ‘heating controls’, with around 158,600 measures installed. Types of measures installed Energy efficiency measures installed under government schemes include: • insulation measures, such as cavity wall, loft and solid wall insulation • boiler measures • microgeneration measures including heat pumps and solar PV • other heating measures, including heating controls • window and door measures Across all schemes to end-December 2025, 53% of measures installed were insulation measures (including window and door measures), while 47% were heating and other non-insulation measures. From 2013 to end- December 2025, the most installed measure types were cavity wall insulation and ‘other heating’ measures, each accounting for 23% of all measures installed, followed by boiler measures, which made up 19%. Less than 1% of measures installed were classified as ‘other’ measures, such as energy efficient lighting or waste water heat recovery systems (Chart 2 and Table 1.3. Note that for purposes of comparison between schemes, measure types are classified slightly differently to how they are presented in Table 3.1). The distribution of measure types varies considerably by scheme, reflecting differences in scheme design and eligibility criteria. Under ECO, delivery has been spread across a wide range of measure types. Over the period to the end of 2025, 24% of ECO measures were cavity wall insulation, 16% loft insulation, and 25% ‘other heating’ measures, 90% of which were heating controls. Boiler measures accounted for 21% of ECO delivery, while micro-generation measures made up a relatively small share, at around 3%. Delivery under GBIS is focused on insulation measures. To the end of 2025, cavity wall insulation accounted for 38% of GBIS measures, while loft insulation accounted for 28%. Solid wall insulation made up around 4% of measures, with ‘other insulation’ measures accounting for 5%. ’Other heating’ measures accounting for 25% of GBIS measures, reflecting the eligibility of heating controls as a secondary measure in some circumstances. Other schemes show measure distributions linked to their specific objectives. Under the Green Deal Framework, solid wall insulation accounted for almost half (49%) of all measures installed, followed by boiler measures at 26%. Under the LAD scheme, microgeneration accounted for 41% of measures, while under HUG, microgeneration made up 48% of measures. In both schemes, most of the microgeneration measures were solar PV. Delivery under SHDF was more evenly distributed, with loft insulation accounting for 25% of measures and microgeneration accounting for 21%. Differences in scheme objectives and eligibility criteria have influenced the types of measures installed over time. While insulation measures account for the majority of installations in total across these schemes, the 6 balance between insulation, heating and low carbon technologies varies, highlighting the importance of scheme level analysis when interpreting aggregate trends. Chart 2: Share of all measures installed by measure type, by scheme, to end-December 2025 (Table 1.3)1 Measures installed in 2025 The breakdown is different for 2025. ECO, HUG, SHDF, GBIS, WH:SHF and WH:LG were the schemes operating. Based on the measure groups in Table 3.1 in 2025, ‘heating controls’ were the most installed at 41%, accounting for 158,600 measures. This was largely driven by ECO. 86% of the heating controls were installed under this scheme. Some of the measures are secondary measures in GBIS that can be installed along with a primary insulation measure. Also, there can be multiple different heating control measures installed in a property. The second most installed measure in 2025 was loft insulation at 16%, followed by solar PV at 10% (Chart 3 and Table 3.1). Chart 3: Measures installed by type of measure, 2025 only (Table 3.1) 1 Micro-generation is made up of heat pumps and solar PV. ‘Other heating’ is made up of heating controls, electric storage heating, district heating and solar thermal. Other insulation is made up room-in-roof, flat roof, floor, and park home insulation, as well as window and door measures. The ‘other’ category is made up of energy efficiency lighting and waste water heat recovery systems. 7 Multiple measures Since 2013 to the end of 2025, an average of 1.68 measures have been installed per household across the schemes presented here. Under ECO, the average is slightly higher at 1.71 measures per household, rising under ECO4 due to its whole-house retrofit focus. From April 2022 onwards, ECO4 has delivered around 4.01 measures per unique household (Table 1.6 from Household Energy Efficiency Statistics, headline release February 2026). The growing difference between the number of measures installed and the number of unique households receiving measures through the iterations of ECO can be seen in Chart 4. Across other schemes up to the end of 2025, households typically received around one or two measures, ranging from 1.33 under LAD and 1.36 under GBIS to 2.11 under SHDF. Chart 4: Cumulative number of ECO measures installed and unique households receiving measures by year, to end-December 2025 (Table 1.1 and Table 1.2) Flexible Eligibility (‘Flex’) The ‘Flexible Eligibility’ rules for ECO4 mean suppliers can now deliver up to 50% of their obligation through this mechanism, up from 25% under ECO3, and 10% under ECO Help-to-Heat (HTH). Ofgem defines ECO4 Flex as, “ECO4 Flex is a household referral mechanism within the wider ECO4 Scheme which enables councils to widen the eligibility criteria for ECO, allowing them to tailor energy efficiency schemes to their respective sector. Under ECO4 Flex, a participating local authority can refer private tenure households that it considers to be living in fuel poverty or on a low income and vulnerable to the effects of living in a cold home”. Since the introduction of Flexible Eligibility (‘Flex’) under ECO at the start of ECO Help-To-Heat (April 2017), 476,000 measures were installed by this mechanism until the end of 2025. The number of ECO Flex measures installed increased at a steady rate each year from its introduction in 2017, up until a previous peak of 75,800 in 2021. ECO Flex installation numbers dropped in 2022, to around 32,300 installations, reflecting the end of the ECO3 phase and slow uptake start at the beginning of ECO4. 8 Flex installation numbers rose again after 2022 to a new peak of 107,700 measures in 2025 (Chart 5 and Table 1.8). Households receiving measures under GBIS can also be referred through the Flexible Eligibility mechanism. Under GBIS suppliers can deliver up to 80% of their GBIS low-income obligation through Flex. To the end of 2025, around 10,700 Flex measures have been installed under GBIS (Table 1.8). Chart 5: ECO and GBIS Flexibility Eligibility measures by installation year, to end-December 2025 (Table 1.8) 9 Household characteristics Tables 4.2 and 4.3 Number of measures installed and households receiving measures by household characteristics, including property type and tenure for the ECO, LAD, HUG, SHDF and GBIS schemes. Headlines • Under ECO, LAD, HUG, SHDF and GBIS to end-December 2025, most properties having measures installed have been houses. • Since 2013, around 2.0 million properties (72%) that have received measures under these five schemes have been houses (where property type was known). • Under ECO, owner occupied households made up the largest share of delivery, accounting for 70% of households since 2013 where tenure was known. Property type of households receiving measures Under ECO, LAD, HUG, SHDF and GBIS to end-December 2025, most properties having measures installed have been houses (Table 4.2). Since 2013, around 2.0 million properties (72% of properties where the property type was known) that have received measures under these five schemes have been houses. For the five schemes, the proportion that were houses ranged from 69% for HUG to 80% for LAD and GBIS (Chart 6 and Table 4.2). In 2025, the percentage of properties that were houses across ECO, HUG, SHDF and GBIS was higher at 78%. Across the five schemes presented here for all years to end-December 2025, 17% were flats. 18% of ECO households receiving a measure were flats (Chart 6). For the year 2025 only, HUG had the highest percentage of flats at 16%. Chart 6: Households in receipt of measures by property type (where known), by scheme to end-December 2025 (Table 4.2) 10 Tenure of households receiving measures Tenure patterns vary by scheme and reflect differences in scheme design and eligibility criteria. Under ECO, owner occupied households made up the largest share of delivery, accounting for 70% of households since 2013 where tenure was known, with the remainder split between the private (14%) and social rented (16%) sectors (Table 4.3 and Chart 7). In 2025, the share of owner-occupied households under ECO decreased to 64%. LAD had a similar tenure profile to ECO, with 71% of households receiving a measure being owner-occupied. Under GBIS, most measure delivery was to owner-occupied households (81%) alongside smaller proportions of private and social rented homes (8% and 11% respectively). Delivery under HUG has been almost entirely to owner-occupied households, reflecting its focus on private- rented and owner-occupied households. In contrast, nearly all households upgraded under SHDF since the scheme started have been in the social rented sector, as the scheme targeted social housing properties (in some cases SHDF delivery could include a small number of non-social rented homes - for example, when retrofitting a whole block of flats that was predominantly social rented). Chart 7: Households in receipt of measures by tenure (where known), by scheme to end- December 2025 (Table 4.3) 11 National and regional trends Tables 3.3 to 3.6, 4.1 The number of measures installed and households receiving measures by country, region, local authority and parliamentary constituency and geographic breakdowns for ECO Flexible Eligibility. Headlines • Across the ECO, GHGV, LAD, HUG, SHDF and GBIS schemes in total, 17% of households upgraded were in the North West of England. This is around 478,300 households. • Scotland and the West Midlands each accounted for 12% of households upgraded. • ECO operates across Great Britain and accounts for the majority of household upgrades. As a result, the distribution of households upgraded across all schemes closely mirrors that observed under ECO alone. National and regional patterns in households upgraded Up to the end of December 2025, an estimated 2.9 million households in Great Britain had received at least one energy efficiency measure through ECO, GHGV, LAD, HUG, SHDF and GBIS. Of these, the North West of England accounted for the largest share, representing 17% of all households upgraded. This is equivalent to around 478,300 households (Chart 7). Note that GHGV, LAD, HUG and SHDF operated in England only. Scotland and West Midlands each accounted for 12% of households upgraded (around 337,000 and 334,000 households respectively). Yorkshire and The Humber accounted for 11%, or around 304,600 households. Other regions accounted for smaller shares of households upgraded. Wales accounted for around 5% of households, equivalent to around 147,600 households upgraded. ECO operates across Great Britain and accounts for the majority of household upgrades. As a result, the distribution of households upgraded across all schemes closely mirrors that observed under ECO alone. Chart 8: Percentage share of households upgraded by nation and region, to end-December 2025 (Table 4.1, Great Britain = 100%) 12 While the North West consistently accounts for a relatively large share of households upgraded across all schemes, the regional distribution varies by scheme (Map 1). ECO and GBIS show broadly similar patterns, with delivery spread across Great Britain and higher shares in the North West, West Midlands and Yorkshire and The Humber. Unlike ECO, GBIS also has a larger share of households upgraded in the North East (11%). LAD has higher shares in the North West (17%) and South East (14%) reflecting differences in local authority participation. HUG delivery is relatively more prominent in the South East (19%) while SHDF delivery is evenly distributed across English regions, with the largest shares in the West Midlands (15%), North East and North West (both 14%). These patterns may reflect a combination of where eligible homes are located, scheme design and eligibility rules, and local delivery participation. In addition, the regions have different population sizes and participating number of grant recipients across Wave 1, Wave 2.1 and Wave 2.2. HUG patterns may be influenced by where off gas-grid homes are more common, for example detached homes in rural areas or blocks of flats in urban areas (see Chart 10). Map 1: Percentage share of households upgraded by scheme, nation and region, to end- December 2025 (Table 4.1, Great Britain or England = 100%)2 2 In Wales and Scotland only the ECO and GBIS schemes are applicable. 13 National and regional trends in measures installed There is a similar regional pattern for the number of measures installed. Some 18% of measures were installed in the North West, and 13% in the West Midlands. Scotland accounted for 10% of measures and Wales 6%. Chart 9: Share of measures installed by nation and region, to end-December 2025 (Table 3.3, Great Britain = 100%) National and regional ECO measures by measure type In addition to variation in regional delivery overall, there is further variability in the types of measures installed in local authorities (Map 2). The maps show the differences in the regional spread of measures, with a higher rate of boiler installations in Wales, the North West and North East regions. There are high rates of delivery for loft insulation across Great Britain, but particularly in Scotland, Wales and parts of England’s northern regions. There are high rates of delivery for cavity wall insulation across local authorities in Great Britain. Scotland and Wales have the highest rates of solid wall insulation delivery. For ‘other insulation’ measures, the rates are low across Great Britain, except for specific local authorities in North Wales, and the North West and Yorkshire and the Humber regions in England. Microgeneration rates are generally low nationally except for mid- and North Wales and some authorities in Scotland. 14 Map 2: ECO measures per 1,000 households, by measure type and local authority, to end- December 2025 Measures installed under government schemes in rural and urban areas Under ECO up to end-December 2025 across Great Britain 16% of measures were installed in rural areas. The urban/rural installation split varies between the nations. Wales has the highest rural share, with 49% of measures installed in rural areas, compared with 19% in Scotland and 12% in England. Within the English regions there is also substantial variation. The South West and East have 34% and 23% of measures installed in rural areas respectively, compared with 6% in the North West and 7% in the West Midlands. This partly reflects the differing urban/rural composition of households across regions. Using the 2021 Rural-Urban classification, all measures in London were installed in urban areas (0% rural). The pattern is broadly similar for GBIS but with a lower rural share overall than ECO. Across Great Britain, 11% of measures were installed in rural areas. By nation, Wales has 29% of measures installed in rural areas, compared with 13% in Scotland and 10% in England. Within England, the region with the largest rural share is the South West (21%), followed by the East (18%), while (aside from London) the North West has the lowest rural proportion (4%). The LAD, HUG and SHDF schemes are only applicable within England. Under LAD, 17% of measures in England were installed in rural areas. The rural share is highest in the South West (32%), East Midlands (30%) and the North East (28%), while it is much lower in the North West (9%). Under SHDF, 26% of measures in England were installed in rural areas, with the South West having the highest rural share (54%), followed by 15 the East Midlands (38%) and the East (37%). Under HUG, there is a much larger rural proportion than in the other schemes with 57% of measures in England installed in rural areas. Across regions for HUG, rural shares range from 42% in the North West to 80% in the East Midlands (and 71% in the East). Chart 10: Percentage of measures installed in rural areas in each nation and region under government schemes, to end-December 2025 (Table 3.6)3 0% rural 3 In Wales and Scotland only the ECO and GBIS schemes are applicable. 16 Costs Tables 5.1 to 5.6 The costs of delivering and administering the ECO and GBIS schemes as reported by energy suppliers, and average measure costs under other government scheme. The text and tables present reported cost data to the end of 2025. Headlines • The total ECO costs reported by suppliers (both delivery and administrative) to the end of 2025 were £11.32 billion. • Up to the end of December 2025 the average cost of delivering the ECO4 obligation, not including ECO3 interim, was around £21.29 per £ annual bill savings. • The total GBIS costs reported by suppliers (both delivery and administrative) to the end of 2025 were £388.1 million. ECO costs Total ECO delivery costs up to end-December 2025 were around £10.68 billion, with an additional £637 million in administrative costs. Therefore, the total cost of ECO was £11.32 billion. Delivery costs in 2025 were 24% lower than in 2024. They were £1.43 billion in 2025, compared to £1.87 billion in 2024. This might in part reflect lower measure delivery in 2025 compared to 2024. Measure installations were 19% lower in 2025 compared to 2024. Note, historic figures are not adjusted for inflation (Table 5.1, Chart 11). Up to end-December 2025 the average cost of delivering the ECO4 obligation, not including ECO3 interim, was around £21.29 per £ annual bill savings (Table 5.2). Chart 11: ECO costs, by obligation, by year, to end-December 2025 (Table 5.1) GBIS costs Total GBIS delivery costs up to the end of 2025 were around £366.0 million, with an additional £22.1 million in administrative costs. Therefore, the total cost of GBIS was £388.1 million. (Table 5.4). Up to the end of December 2025 the average cost of delivering the GBIS obligation was around £25.44 per £ annual bill savings (Table 5.5). 17 Estimates of home insulation levels in Great Britain Tables 7.1 to 7.7 Estimates of the number of homes in Great Britain (GB) with loft, cavity wall and solid wall insulation. The section gives headline estimates for the number of insulated properties and sets out the remaining potential for insulation to be installed in properties in GB. Estimates of insulation levels are started from April 2013 to reflect information available in the English, Welsh and Scottish Housing Surveys close to the start of the ECO and Green Deal schemes. These estimates show the share of homes with loft, cavity wall and solid wall insulation separately for England, Wales and Scotland. Full details on how these estimates were constructed can be found in the Methodology note. Headlines • Of the estimated 21.8 million homes in Great Britain with cavity walls, 71% have cavity wall insulation. • Of the estimated 26.3 million homes in Great Britain with lofts, 67% have loft insulation (at least 125mm). • Of the estimated 8.5 million homes in Great Britain with solid walls, 11% have solid wall insulation. • 2.3 million major professional insulation measures (cavity wall, loft and solid wall) have been installed through government supported domestic energy efficiency schemes since 2013. Professional insulation measure installations through government schemes A total of 2.3 million major professional insulation measures (cavity wall, loft and solid wall) have been installed through government supported domestic energy efficiency schemes in Great Britain since 2013 (Chart 11). While the number of measures delivered per year has generally fallen from levels seen 2013 to 2015, largely as the size of the ECO obligation has been reduced, the focus of schemes has changed to target measures with greater energy and carbon savings and to target schemes towards more vulnerable households. Chart 12: Cumulative professional insulation measures installed through government energy efficiency schemes, Great Britain 2013-2025 (Table 7.3) 18 Housing stock The housing stock in Great Britain is made up of properties with different characteristics, such as cavity walls or solid walls. It is important to understand the profile of the housing stock because different insulation measures are suitable for different property types. Infographic 1: Housing stock estimates to the end of 2025 Levels of insulation Estimating levels of insulation types in the housing stock makes it possible to see both how much progress has been made to date and how much work there is left to do. At the end of December 2025 in Great Britain: • 15.4 million homes had cavity wall insulation (71% of homes with a cavity wall) • 909,000 had solid wall insulation (11% of homes with solid walls) • 17.7 million had loft insulation (67% of homes with a loft) Through 2025, both retrofit insulation (delivered through Government schemes4,5) and new properties6 built with insulation in Great Britain resulted in the following progress: • around 195,800 more homes with cavity wall insulation (a 1.3% increase between the end of December 2024 and December 2025), of which 31,500 were through retrofit and 164,300 through new build. • approximately 212,100 more homes with at least 125mm of loft insulation (a 1.2% increase between the end of December 2024 and December 2025), of which 64,600 were through retrofit and 147,500 through new build. • around 29,600 more homes with solid wall insulation (a 3.4% increase between the end of December 2024 and December 2025), all of which are assumed to be through retrofit. Remaining potential A key use of these estimates for DESNZ is to identify how many homes have the potential to receive cavity wall, loft or solid wall insulation in the future. 4 Insulation measures delivered in Scotland exclusively under the Green Homes Cashback scheme are excluded from the figures. 5 The estimates of progress for 2025 include the delivery of insulation through the HUG, SHDF, WH:SHF and WH:LG schemes, as well as ECO and GBIS. 6 Information is not available on the wall construction of new homes. Building regulations would typically be met by insulated cavity walls but other construction types could be used with an equivalent insulating performance. In this publication, it is assumed that all new builds since April 2013 have cavity wall insulation. Around 164,300 new builds were completed in 2025 in GB, based on new builds data from England, Wales and Scotland (DESNZ and devolved governments’ data). 19 Both historical figures and a more detailed breakdown of Great Britain’s remaining insulation potential are available in Tables 7.4 - 7.6 of the accompanying Excel tables. Chart 13 gives a summary of the remaining potential for insulating properties in Great Britain. Chart 13: Remaining potential to insulate the housing stock in Great Britain, end-December 2025 (Tables 7.4, 7.5 and 7.6)7 Remaining potential – cavity wall insulation At the end of December 2025, there were an estimated 21.8 million homes with cavity walls in Great Britain (Chart 13, Table 7.4). Of these, 15.4 million (71%) were estimated to have cavity wall insulation. There were also around 1.3 million homes that may or may not have cavity wall insulation due to the level of uncertainty from the survey of what is insulated. Of the remaining approximate 5.0 million homes without cavity wall insulation, we estimate that 3.7 million have easy to treat standard cavities and 1.3 million are hard to treat.8 Remaining potential – loft insulation Lofts are defined as insulated in this report if they have 125mm or more of insulation. This report defines lofts with less than 125mm of insulation as uninsulated as they would benefit most from top-up insulation. At the end of December 2025, there were an estimated 26.3 million homes with a loft in Great Britain (Chart 13, Table 7.5). Of these, 17.7 million (67%) were estimated to have loft insulation. There were also around 0.8 million homes that may or may not have had loft insulation due to the level of uncertainty from the survey of what is insulated and uncertainty whether new build homes have lofts. Of the remaining approximate 7.7 million homes without loft insulation, 5.5 million were estimated to have easy to treat lofts and 2.2 million were considered to have hard to treat or unfillable lofts which means that the loft would be hard or costly to insulate or could not be insulated at all. This can occur in properties with a flat roof, properties with a room in their roof, or properties where the roof has a very shallow pitch, which makes the loft space inaccessible. 7 Includes where it is not certain if a property has cavity walls or a loft. 8 Hard to treat cavities are ones that are more difficult or more expensive to fill than standard cavities. This includes properties with a narrow cavity and properties of either concrete or metal frame construction. The definition of hard to treat used in this publication is based on the definition used in the 2013 Housing Surveys. The ECO definition of hard to treat differs from this definition slightly as it also includes partial fill cavities and cavity wall properties over three storeys (compared to over four). It also excludes some cavities which assessors would not be able to identify as hard to treat, such as properties with high exposure to wind and rain. 20 Remaining potential – solid wall insulation Solid wall insulation has been defined throughout this report as internal or external wall insulation installed through government programmes. At the end of December 2025, there were an estimated 8.5 million homes with solid walls in Great Britain (Chart 13, Table 7.6). Of these, it is estimated that 909,000 (11%) had solid wall insulation and 7.6 million (89%) were uninsulated. 21 Benefits monitoring Tables 2.2 to 2.3 This section sets out the combined number of measures installed across the schemes, plus the estimated carbon and energy savings from those measures. Headlines • To end-December 2025, provisional estimated annual carbon savings of measures installed through LAD, HUG, GHGV and SHDF was up to 0.0969 MtCO2. • To end-December 2025, provisional estimated annual energy savings of measures installed through LAD, HUG, GHGV and SHDF was up to 471 GWh. • To end-December 2025, provisional estimated annual bill savings of measures installed through LAD, HUG, GHGV and SHDF was £25.2m. • The total estimated annual bill savings to end-December 2025 from measures installed under the ECO4 obligation was £210.5m. Carbon, energy and bill savings under LAD, HUG, GHGV and SHDF The carbon, energy and bill savings associated with measures installed through the LAD, HUG, GHGV, and SHDF schemes are based on annual savings. The figures are estimated using modelled consumption values from the National Housing Model (NHM). More information on the methodology used can be found here: https://www.gov.uk/government/publications/green-homes-grant-vouchers-statistics-methodology-note To the end of December 2025, the provisional estimated annual carbon savings, annual energy savings and annual bill savings under these schemes was 0.0969 MtCO2, 471 GWh and £25.2m respectively (Table 1 below and Table 2.2). Table 1: Estimated Annual Energy, Carbon and Bill Savings for installed measures through LAD, HUG, GHGV and SHDF, to end-December 2025 (Table 2.2) Scheme LAD1 LAD2 LAD3 HUG1 HUG2 GHGV SHDF Wave 1 SHDF Wave 2.1 SHDF Wave 2.2 Total Estimated Annual Energy Saving (GWh) 40 37 32 11 39 130 52 119 11 471 Estimated Annual Carbon Saving (MtCO2) 0.0083 0.0077 0.0066 0.0026 0.0093 0.0241 0.0107 0.0252 0.0023 0.0969 Estimated Annual Bill Saving (£) £2.2m £2.3m £1.9m £0.8m £3.0m £3.9m £3.1m £7.4m £0.7m £25.2m Under all these schemes except HUG, solid wall insulation accounted for most of these savings out of all measures installed. Under the combined LAD phases, solid wall insulation made up 18% of the measures with modelled estimated savings but 52% of the estimated annual energy savings (Table 2.2). 22 Under HUG1 and HUG2, the installation of heat pumps accounted for most of the energy, carbon and bill saving. Under HUG2 for example, heat pumps made up around 19% of measures with modelled estimated savings attached but 61% of the estimated annual energy savings. (Table 2.2). Annual bill savings under ECO4 Under ECO4, each measure installed, or project completed receives a score which determines the contribution made towards a supplier’s Home Heating Cost Reduction Obligation (HHCRO). The scores are based on the annual bill saving achieved by a measure or package of measures when installed in a domestic premises. Suppliers are required to achieve a total of £224.3 million in annual bill savings. Not all measures have a score assigned so far, so actual progress towards the obligation is likely to be higher than this report indicates. To the end of December 2025, the total estimated annual bill savings from measures installed under ECO4 HHCRO were £210.5m. This includes savings from measures installed under ECO3 Interim and measures installed prior to April 2022 that have been re-elected as ECO4 measures. (Table 2.3). Upgrades to EPC bands for LAD, HUG and SHDF These three schemes present statistics changes in the EPC rating of households from measures being installed under LAD, HUG and SHDF from October 2020 to December 2025. Of the households treated through LAD, HUG and SHDF initially rated EPC band D or lower, 75% were upgraded to EPC band C or above (Table 4.4). 23 Technical Information Data in this release Data are collected by DESNZ from a range of administrative sources. For these statistics, the main sources of data on the schemes are: • Ofgem for ECO and GBIS data – scheme administrator collects data from energy companies on ECO and GBIS delivery • Green Deal Central Charge Database – administer and manage Green Deal Plans • NEC Software Solutions UK – manage national lodgement of Green Deal measures • Energy Savings Trust Scotland (EST) – manage lodgement of Green Deal measures in Scotland • Green Deal Oversight and Regulation Body (ORB) – administer Green Deal organisations certification • ICF for Green Homes Grant Vouchers (GHGV) data – scheme administrator who collected data from applicants (householders and landlords) and installers on GHGV delivery. • Local authorities and Local energy hubs for Green Homes Grant Local Authority Delivery (LAD) and Home Upgrade Grant (HUG) data – administer scheme funding so collect data from householders and installers on delivery. • Registered providers of social housing (including private and local authority providers) for the Social Housing Decarbonisation Fund (SHDF) – administer scheme funding so collect data from householders and installers on delivery. • Local authorities; combined authorities; registered providers of social housing (including housing associations and arms-length management organisations (ALMOs) that are registered providers); and registered charities that own social housing for the WH:SHF • Local authorities who were successful in participating in the WH:LG scheme. Funding allocations were made to Local Authorities in early 2025. 74 projects involving 271 LAs (over 97% of eligible LAs in England) were allocated funding. Information on these schemes can be found in the Methodology note for this release. Further administrative datasets are used to provide the geographic breakdowns included in this release. Reference geography datasets and map boundary files are obtained from the Office for National Statistics (ONS), through the Open Geography Portal. Methodology The statistics presented in this release cover measures installed up to end-December 2025. Further information regarding the methodology and quality assurance process used to produce estimates for this statistical series can be found here: Household Energy Efficiency Statistics Methodology Note Revisions policy Figures for the latest periods are provisional and are liable to subsequent revision. The DESNZ statistical revisions policy sets out the revisions policy for these statistics, which has been developed in accordance with the UK Statistics Authority Code of Practice for Statistics. 24 Further Information Recent publications of interest Green Homes Grant Local Authority Delivery and Home Upgrade Grant statistics For statistics monitoring the Green Homes Grant Local Authority Delivery and Home Upgrade Grant schemes across England, see the Green Homes Grant Local Authority Delivery statistics. Social Housing Decarbonisation Fund statistics For statistics monitoring the Social Housing Decarbonisation Fund scheme across England, see the Social Housing Decarbonisation Fund statistics. Great British Insulation Scheme statistics For statistics monitoring the Great British Insulation Scheme across Great Britain, see the Great British Insulation Scheme statistics. Warm Homes: Social Housing Fund statistics Data to monitor the installation of energy efficiency measures in domestic properties via the Warm Homes: Social Housing Fund (WH:SHF) scheme in England. See Warm Homes: Social Housing Fund statistics. Warm Homes: Local Grant statistics Data to monitor the installation of energy efficiency measures in domestic properties via the Warm Homes: Local Grant (WH:LG) scheme in England. See Warm Homes: Local Grant statistics. Smart Meters quarterly statistics For estimates on the roll-out of Smart Meters in Great Britain, covering meters operating and meters installed, see the Smart Meters statistics. Energy Trends For detailed data on supply and demand of coal, oil, gas, electricity and renewables in the United Kingdom, see the Energy Trends statistics. Energy Consumption in the United Kingdom (ECUK) For detailed data on end use estimates of energy in the UK, see the Energy Consumption in the United Kingdom (ECUK) statistics. Sub-national total final energy consumption For findings of the sub–national energy consumption analysis in the UK for all fuels, for the period covering 1 January to 31 December, with gas consumption covering the annual period from mid-May, see the sub- national total final energy consumption statistics. Sub-national electricity consumption For electricity consumption by consuming sector for Great Britain and devolved administration areas, see the sub-national electricity consumption statistics. Data are based on the aggregation of Meter Point Administration Number readings as part of DESNZ’s annual meter point electricity data exercise. Sub-national gas consumption For gas consumption by consuming sector for Great Britain, and devolved administration areas, see the sub- national gas consumption statistics. Data are based on the aggregation of Meter Point Reference Number readings throughout Great Britain as part of DESNZ’s annual meter point gas data exercise. Domestic Energy Interactive Map For an interactive map for indicators of domestic energy efficiency, including the percentage of households receiving ECO measures down to Lower Layer Super Output Area up to December 2024, see the Domestic Energy Map. The map also shows the number of loft and wall insulation measures installed. 25 National Energy Efficiency Data-Framework (NEED) The National Energy Efficiency Data-Framework (NEED) was set up to provide a better understanding of energy use and energy efficiency in domestic and non-domestic buildings in Great Britain. The data framework matches gas and electricity consumption data, collected for DESNZ subnational energy consumption statistics, with information on energy efficiency measures installed in homes, from government schemes. It also includes data about property attributes and household characteristics, obtained from a range of sources. See National Energy Efficiency Data-Framework (NEED). Future updates to these statistics The next ECO headline release on the GOV.UK website is planned for publication at 9.30am on 26 March 2026 and will contain the latest available information on headline ECO measures up to the end of January 2026. National statistics This is an accredited official statistics publication. Accredited official statistics are called National Statistics in the Statistics and Registration Service Act 2007. These accredited official statistics were independently reviewed by the Office for Statistics Regulation (OSR) in June 2014. They comply with the standards of trustworthiness, quality and value in the Code of Practice for Statistics and should be labelled ‘accredited official statistics’. Our statistical practice is regulated by the Office for Statistics Regulation (OSR). OSR sets the standards of trustworthiness, quality and value in the Code of Practice for Statistics that all producers of official statistics should adhere to. You are welcome to contact us directly with any comments about how we meet these standards. Alternatively, you can contact OSR by emailing regulation@statistics.gov.uk or via the OSR website. Pre-release Some ministers and officials receive access to these statistics up to 24 hours before release. Details of the arrangements for doing this and a list of the ministers and officials that receive pre-release access to these statistics can be found in the DESNZ statement of compliance with the Pre-Release Access to Official Statistics Order 2008. Uses of these statistics These statistics are used by Government to monitor the delivery and effectiveness of different household energy efficiency schemes. They are used to monitor the delivery of the ECO obligation and the share of the obligation delivered though key aspects of the scheme, including Flexibility Eligibility and innovation measures. The data are used within the National Energy Efficiency Data-framework to assess the impact of these measures in different types of homes. User engagement Users are encouraged to provide comments and feedback on how these statistics are used and how well they meet user needs. Comments on any issues relating to this statistical release are welcomed and should be sent to the Energy Efficiency Statistics mailbox. The DESNZ statement on statistical public engagement and data standards sets out the department’s commitments on public engagement and data standards as outlined by the Code of Practice for Statistics. Contact • Responsible statistician: Darren Stillwell • Email: EnergyEfficiency.Stats@energysecurity.gov.uk • Media enquiries: 020 7215 1000 26 © Crown copyright 2026 This publication is licensed under the terms of the Open Government Licence v3.0 except where otherwise stated. To view this licence, visit the National Archives website or write to the Information Policy Team, The National Archives, Kew, London TW9 4DU, or email the National Archives Public Sector Information mailbox. Where we have identified any third-party copyright information you will need to obtain permission from the copyright holders concerned. This publication is available on Gov.uk by following the link here. If you need a version of this document in a more accessible format, please email the Energy Efficiency Statistics mailbox. Please tell us what format you need. It will help us if you say what assistive technology you use. 27