Household Energy Efficiency statistics methodology note

The methodology note summarises the methodology used to produce estimates of various elements of the Energy Company Obligation (ECO), Domestic Green Deal (GD) and levels of insulation in Great Britain. It is intended to help users understand the assumptions made in the compilation of these statistics and some of the limitations of the data sources. The background quality report summarises the quality assurance relating to statistics on ECO, GD and insulation levels in Great Britain. --- Household Energy Efficiency Methodology Note Household Energy Efficiency Statistics: Methodology note March 2026 Accredited Official Statistics Contents Contents ______________________________________________________ 1 Summary of data sources _________________________________________ 2 Scheme Information _____________________________________________ 3 Data quality of data sources _______________________________________ 7 Users/uses of the report __________________________________________ 8 ECO measures (headline and detailed releases) ______________________ 10 ECO households (headline and detailed release) ______________________ 12 ECO Brokerage (discontinued series) _______________________________ 14 Green Deal Assessments (discontinued series) _______________________ 14 Green Deal Communities (discontinued series) _______________________ 17 Green Deal Plans (headline and detailed releases) ____________________ 20 Measures installed using Green Deal finance (detailed release) __________ 22 Measures captured by administrative data sources (headline release)______ 23 Households that have had measures installed and captured by administrative data sources (headline release) ___________________________________ 23 Green Deal Home Improvement Fund (discontinued series) _____________ 24 Upgrading one million homes target, (May 2015 – April 2020) (discontinued series as target period finished) ___________________________________ 25 Households with at least one usual resident (headline and detailed releases) 29 Estimating carbon and energy savings (headline and detailed release) _____ 30 Home insulation levels in Great Britain (detailed release) ________________ 37 Reporting methodology __________________________________________ 50 Revision’s policy _______________________________________________ 50 Further information and feedback __________________________________ 51 1 Household Energy Efficiency Methodology Note Summary of data sources The estimates use administrative data generated as part of the Green Deal (GD) and Energy Company Obligation (ECO) processes. For the annual detailed statistical release, scheme administrative data from the Green Homes Grant Vouchers (GHGV), the Social Housing Decarbonisation Fund (SHDF), the Great British Insulation Scheme (GBIS), Green Homes Grant Local Authority Delivery (LAD) scheme, Home Upgrade Grant (HUG), the Warm Home: Social Housing Fund (WH:SHF) and Warm Home: Local Grant (WH:LG) are included in some tables to provide a broader overall view of household energy efficiency schemes. In addition, the estimates of home insulation levels use data contained within the national housing surveys and published by the Ministry of Housing, Communities and Local Government (MHCLG), Welsh Government and National Records of Scotland to build up an overall picture of the housing stock in Great Britain. There are several sources of administrative data used to produce these statistics – each report will state which sources have been used, based on the content being included: • Ofgem – who administer the Energy Company Obligation (ECO) and the Great British Insulation Scheme (GBIS) and collect information from energy companies on measures installed under ECO and GBIS, and associated costs. • Green Deal Central Charge Database – which manage the recording and administration of Green Deal Plans. • NEC Software Solutions UK – who manage the national lodgement of Green Deal measures in England and Wales. NEC Software Solutions UK (formerly Northgate) took over the scheme management from Landmark in September 2017. • Energy Savings Trust Scotland (EST) – who manage the national lodgement of Green Deal measures in Scotland. • GHGV scheme delivery partner – who administered the Green Homes Grant Voucher (GHGV) scheme. The delivery partner collected data from applicants and installers on vouchers applied for, measures installed and associated costs. • Local LAD Local authorities (LAs) and Local Energy Hubs – who administer funding for household energy efficiency measures under LAD and HUG and who were successful with bids for funding under the LAD and HUG competitions. The scheme is administered in phases, with LAD Phase 1 administered directly through LAs, LAD phase 2 is through the local energy hubs, and LAD Phase 3 and HUG directly through LAs. Data is collected on the households’ receiving measures and the measures installed. 2 Household Energy Efficiency Methodology Note • Local authorities and registered providers of social housing for the Social Housing Decarbonisation Fund (SHDF) – who 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. • National housing surveys – which collect data on the housing stock in England, Wales, and Scotland. • MHCLG – which produce information on the number of properties in the housing stock and new builds. • Inbuilt – a report produced by Inbuilt is used to inform estimates on the number of hard-to-treat cavity wall properties in the housing stock. • Office for National Statistics (ONS) – which produce map boundary files and geography lookup tables. • ONS, Welsh Government and National Records of Scotland - households with at least one usual resident. After appropriate quality assurance, the data from these data sources are used to produce the headline and detailed estimates included in Accredited Official Statistics releases. We will continue to update the detail on each part of the methodology as we publish more information in the headline and detailed Accredited Official Statistics releases. In addition, the statistics on insulation levels which make use of Accredited Official Statistics from national housing surveys/other data sources rely on the data quality assurance processes as published by the producing departments. Scheme Information This section gives information about different energy efficiency schemes that are presented in the detailed Annual Household Energy Efficiency statistics release. The Energy Company Obligation (ECO) was introduced in January 2013 to reduce energy consumption and support people at greater risk of living in fuel poverty. The larger energy companies are set obligations to install insulation and heating 3 Household Energy Efficiency Methodology Note measures to achieve reductions in energy usage and heating costs. ECO is now in its fourth iteration since it began. Broadly, ECO takes over from two previous Energy Obligation schemes: Carbon Emissions Reduction Target (CERT) and Community Energy Saving Programme (CESP). The current ECO4 scheme focuses on providing energy efficiency measures to low income and vulnerable consumers and compared to previous ECO schemes requires a more complete upgrade of homes, shifting to a multi-measure whole-house retrofit approach. • ECO1 started on 1 January 2013 (although energy companies were able to count measures delivered since 1 October 2012 against their targets) and ran until 31 March 2015. • ECO2 commenced in April 2015 and ran until 31 March 2017. • ECO Help-to-Heat commenced in April 2017 and ran until September 2018. • ECO3 commenced 3 December 2018 (although suppliers could count measures delivered since October 2018 against their targets) and ran until 31 March 2022. • • ECO4 commenced on 27 July 2022 (although installations between 1 April and 30 June 2022 could be counted as either ‘ECO3 Interim Delivery’ or ‘ECO4 Early Delivery’). In August 2025, the Department for Energy Security and Net Zero consulted on proposals to extend the ECO4 end date, as set out in Extending the ECO4 end date: consultation document. One of the final policy decisions of the consultation was that ECO4 will be extended by nine months, ending on 31 December 2026, to allow suppliers additional time to meet existing targets and remediate non-compliant installations. The Green Deal (GD)1 is a government initiative that is designed to help homeowners install energy efficiency measures into their properties, and the costs of these measures are paid back through their energy bill over a period of time; this is in the form of a Green Deal Finance Plan (GD Plan). The Green Homes Grant Vouchers (GHGV) scheme launched for applications on 30th September 2020 and closed to new applicants on 31st March 2021. It was available in England only. Householders and landlords could apply for a grant of up to £10,000 to cover the cost of installing energy efficiency measures. The scheme was split into a main scheme and a low-income scheme, which was determined by the receipt of certain benefits. Applicants on the main scheme would receive up to two-thirds of the cost of the retrofit up to a value of £5,000, while low-income applicants would be fully funded up to £10,000. Further information on the scheme is available in the official statistics2 and GHGV guidance3. The Green Homes Grant Local Authority Delivery (LAD) scheme launched in 2020 with £500 million of funding to support the energy efficiency upgrades of low-income households across England. LAD was delivered over different phases, with Phase 1 allocating £200m in grants to over 136 Local Authorities for delivery by March 2022. Phase 2 allocated £300m in grants to the five Local Net Zero Hubs, who will work 1 https://www.gov.uk/green-deal-energy-saving-measures 2 https://www.gov.uk/government/collections/green-home-grant-statistics 3 https://www.gov.uk/guidance/apply-for-the-green-homes-grant-scheme 4 Household Energy Efficiency Methodology Note with their regional Local Authorities. Under the scheme, LAs identify households that meet the eligibility criteria for the scheme - these were targeted as those most at risk of fuel poverty or in the least energy efficient housing. The Sustainable Warmth (SW) scheme launched in early 2022 to further support the energy efficiency upgrades of low-income households across England. SW consists of LAD Phase 3 and the Home Upgrade Grant (HUG) Phase 1. LAD Phase 3 was allocated £287 million funding to Local Authorities to support low-income homes on the gas grid, whilst HUG Phase 1 was allocated £220 million funding to Local Authorities to support low income homes off the gas grid. HUG Phase 2 was allocated up to £630 million of funding available for successful local authorities to deliver from September 2023 until March 2025. Further information on the LAD and HUG schemes is available in the official statistics4. The Social Housing Decarbonisation Fund (SHDF) scheme is a government scheme that will upgrade a significant amount of the social housing stock currently below Energy Performance Certificate (EPC) C up to that standard. It supports the installation of energy performance measures in social homes in England. The Government launched Wave 1 of the SHDF in August 2021. It was awarded around £179m of grant funding for delivery from 2022 into 2023 and will see energy performance improvements to up to 20,000 social housing properties. Successful projects within Wave 2.1 of the SHDF were announced on 22 March 2023. Wave 2.1 of the SHDF was awarded around £778m of grant funding, delivering from 2023 to 2025. Wave 2.2 of the SHDF awarded around £80m of grant funding for delivery from 2024 to 2026. Further information on the scheme is available in the official statistics5. The Great British Insulation Scheme was announced by the Government at the end of March 2023. The £1 billion scheme will help around 300,000 households across the country with the cost of installing new home insulation. The scheme is scheduled to run until March 2026. GBIS will run alongside ECO4. Legislation relating to the scheme came into force on 25 July 2023, with delivery on or after 30 March until 24 July 2023 being known as early delivery measures. Further information on the scheme is available in the official statistics6. The Warm Homes: Local Grant Scheme was allocated £500m as part of the Autumn Budget 2025. Participating local authorities will use the funding to install energy performance upgrades and low carbon heating. The Warm Homes: Social Housing Fund Scheme was allocated £1.29 billion as part of the 2025 Autumn Budget. It will upgrade a significant amount of the social housing stock currently below Energy Performance Certificate (EPC) band C up to that standard. It will support the installation of energy performance measures in social homes in England. 4 https://www.gov.uk/government/collections/green-home-grant-statistics 5 https://www.gov.uk/government/collections/social-housing-decarbonisation-fund-statistics 6 https://www.gov.uk/government/collections/great-british-insulation-scheme 5 Household Energy Efficiency Methodology Note Definitions Energy Company Obligation (ECO) requires the larger energy suppliers to achieve savings in homes. There have been three main ECO obligations, which are detailed in the table below. The table also identifies defines Flexible Eligibility and Innovation, which are sub-obligations operating under ECO4. CERO & CSCO were measured in terms of lifetime carbon savings. Affordable Warmth was measured in terms of lifetime bill savings under ECO3 but is now measures in terms of annual bill savings for ECO3. Energy Suppliers are set targets for each phase of the scheme based on two criteria: the number of customers that they have and the amount of energy that they supply to domestic properties in Great Britain. This threshold remained the same for ECO1, 2 & Help-to-Heat but it is tightened through ECO3. Targets for ECO4 have remained the same as ECO3. The targets are as follows: • Number of domestic customers must be 150,000 or more • Electricity supply to domestic customers must be 300 GWh or more • Gas supply to domestic customers must be 700 GWh or more Suppliers are obligated to participate in the scheme if they exceeded both the customer number threshold and the electricity or gas supply threshold as of 31 December of the previous year. Carbon Emission Reduction Obligation (CERO) Carbon Saving Communities (CSCO) Affordable Warmth or The Home Heating Cost Reduction Obligation (HHCRO) This covered the installation of measures like solid wall and hard-to-treat cavity wall insulation, which ordinarily cannot be financed solely through Green Deal Plans. The obligation was measured in terms of lifetime carbon savings. From April 2017 this included a rural sub-obligation where at least 15 per cent of a supplier’s CERO for Help-to-Heat must be achieved in rural areas. (Closed end September 2018). This provides insulation measures to households in specified areas of low income. The obligation was measured in terms of lifetime carbon savings. It required 15 per cent of each supplier’s obligation to be used to upgrade more hard-to-reach low-income households in rural areas. (Closed end March 2017) This provides heating and insulation measures to consumers who receive particular means-tested benefits. Since April 2017 it enables those in social housing living in E, F and G rated properties to receive insulation measures, and some heating measures. This obligation supports low-income consumers who are vulnerable to the impact of living in cold homes, including the elderly, disabled and families. Under ECO4, 100% of the obligation is based on HHCRO. The obligation was measured in terms of annual bill savings (previously measured in terms of lifetime savings for ECO3). 6 Household Energy Efficiency Methodology Note Flexible Eligibility Local Authorities can determine eligible homes under the new ‘Flexible Eligibility’ mechanism, introduced in 2017. Up to 50% of the Obligation can be delivered through Flexible Eligibility under ECO4, up from 25% under ECO3. Households can be assessed by Local Authorities, the Devolved Administrations or suppliers to be 'living in fuel poverty'; or assessed to be 'living on a low income and vulnerable to cold'. Innovation Measures Under ECO4, suppliers are able to meet up to 10% of their obligation to deliver innovation measures to eligible households. A further 10% can be used to monitor the actual energy performance of measures in homes. Data quality of data sources The administrative data sources listed above are all subject to a range of data quality checks employed by both data providers and the Department for Energy Security and Net Zero (DESNZ) to ensure that data are as fit for purpose as possible. These checks are summarised below: NEC Software Solutions UK / Energy Savings Trust Scotland (EST) NEC Software Solutions UK manage the Green Deal measures data for England and Wales. The Energy Savings Trust Scotland (EST Scotland) manage the equivalent data for Scotland GD plans. In addition to the data provided by NEC Software Solutions UK and EST, some data on Energy Performance Certificates associated with Green Deal plans are used to identify the date the plan went live and the details of the finance plan from publicly available sources for the EPC registers. Green Deal Central Charge Database The Green Deal Central Charge (GDCC) database is used by electricity suppliers and Green Deal Providers and is governed by, and made available under, the Retail Energy Code (REC). The Retail Energy Code Company (RECCo) is responsible for operating the service and has the role of implementing any necessary changes to the REC to support the implementation of the Green Deal. The GDCC stores Green Deal Plan charge data that facilitates the collection and remittance of Green Deal payments in Green Deal Plans. The database contains all financial information and controls the information/data flows which are required as part of the Green Deal. There are many data checks to ensure that GD Plan data is accurately registered and can be accessed by the relevant participants. This database is mainly used to determine the Green Deal Plan Record Statuses. The GDCC provides a status flag in relation to the Green Deal Plan record and has logical rules regarding status transition. So, for example, for a Green Deal Plan to be “LIVE” there was a check to ensure the Green Deal Charge information was sent to the Green Deal Licensee and 7 Household Energy Efficiency Methodology Note the Green Deal Licensee confirmed that the Supplier Verification was successful in relation to that request. The functions of the GDCC Database permit: • Registering of a Green Deal Plan. • Recording of relevant data for each Green Deal Plan. • Update to relevant data by organisations, including the validation of such data. • Information exchange between relevant GDCC users, which information shall include confirmations and rejections as well as data exchange. • Access to data records, flows, logs, and any other relevant information as may reasonably be expected or required under any audit pursuant to the REC. Ofgem Ofgem undertake comprehensive validation checks on the ECO measures (including ECO1, ECO2, ECO Help-To-Heat, ECO3, ECO3 Interim and ECO4 periods) reported by energy suppliers in the month following receipt of data. These include data correction or completion of missing information. Ofgem also undertakes technical monitoring, longer-term audits that are completed over the obligation period to verify the installation of the measures, the quality of installations and to ensure compliance with the ECO guidelines. These involve further scrutiny of measures installed which may also involve site visits to properties. Users/uses of the report A user consultation was launched on 20 August 2015 to seek views on several proposals to the previous statistical series on the Green Deal and Energy Company Obligation. The consultation and response (published on 19 November 2015) can be found here: DECC household energy efficiency national statistics user consultation (opens in new window) The user consultation also sought views from key users on which statistics they were using and what they used them for. The responses received showed that these statistics had a wide audience covering the following sectors: energy suppliers, energy industry organisations, consumer protection organisations, Central Government/Agency, and Local Authorities. The department also consulted with internal colleagues, which highlighted that the statistics published in the headline release are used by analytical and policy colleagues to monitor the GD/ECO policy through regular, quality assured figures. The consultation responses showed there was a need to provide regular detail on ECO. Respondents viewed the ECO tables as a key source of data for the ECO 8 Household Energy Efficiency Methodology Note supply chain, including assessors, installer organisations, and obligated companies (i.e., energy suppliers). They used the tables to monitor overall progress towards the obligation. It was felt that stopping the release of ECO information on a monthly basis would have a detrimental effect on the ECO supply chain due to the data lag. Respondents also felt the ECO tables were needed monthly as it approached the end of the delivery phase so that progress could be closely monitored. Respondents were less concerned about statistics relating to the GD moving to a quarterly reporting frequency – it was felt that this information was now less relevant due to the announcement made by DECC in July 2015, and that overall it was less critical to their own needs. From December 2015 (following the consultation response) this statistical series has made the following changes: • In response to concerns expressed by some respondents, the frequency of any ECO only related statistics has not been reduced. • Headline figures on Green Deal related statistics previously published monthly, are now released on a quarterly basis, except for Cashback, Green Deal Home Improvement Fund and Green Deal Communities (as all these schemes have now closed). • Detailed figures on Green Deal related statistics, insulation levels and interactions between other schemes (e.g., Feed-in Tariffs) previously published quarterly, will now be released on an annual basis. • Improved design and accessibility of the tables (including detailed time series breakdowns) and accompanying commentary. The routine publication of these statistics following Accredited Official Statistics guidelines has allowed reporting to be based on the latest, independently published figures. The releases continue to reflect policy and external interest by, for instance, including geographic breakdowns. As well as providing a regular evidence base for users, this enables Parliamentary Questions and other enquiries to be answered in a robust and transparent manner. There has been a sustained demand for figures on ECO. These are used by colleagues in DESNZ and across Government to evaluate the number and type of measures being installed and, in conjunction with Ofgem’s ECO1 compliance report, CSCO compliance report, ECO2 Final Determination Report and ECO3 Final Determination Report, energy suppliers’ delivery against their obligations. Information on the costs of delivering ECO, published quarterly in the headline release, is used across Government to estimate the overall cost of the scheme. This facilitates public accountability and allows energy suppliers to benchmark their own costs against the average for each obligation. There is also strong local and regional interest in the figures. Headline releases present ECO measures and individual households by Local Authority and Parliamentary Constituency. These breakdowns help demonstrate to the supply 9 Household Energy Efficiency Methodology Note chain where demand for energy efficiency measures is focussed. ECO is also a Great Britain-wide policy, and the regular publications of these figures are used by the Devolved Administrations and Local Authorities to demonstrate how many measures have been installed in specific areas. The insulation levels section of the detailed release is used by DESNZ and industry to view estimates on how many homes in Great Britain currently have cavity wall insulation, loft insulation and solid wall insulation. The statistics also allow monitoring of how many homes have been insulated through the rollout of various Government schemes since March 2013. It can also be used to estimate the number of homes that have the potential to receive insulation in the future (including a split by easy and hard to treat properties) – this is important when new policies are being developed as it is possible to estimate the number of homes that could receive insulation under a specific policy. Similarly, this information can be used by the supply chain to gauge the likely demand for specific energy efficiency measures. ECO measures (headline and detailed releases) ECO-obligated energy suppliers notify Ofgem of installed measures, with a one- month lag between the installation period and notification date (e.g., measures installed up to the end of August were notified to Ofgem by the end of September to be published in October). Under ECO3, the data at this initial stage were unprocessed by Ofgem and were shared with DESNZ early the following month. The December 2015 headline statistics release uses the final ECO 1 processed data, following Ofgem’s final compliance report of ECO1 measures (January 2013 – March 2015). Ofgem would undertake comprehensive validation checks on the measures reported by energy suppliers in the month following receipt of data and longer-term audits completed over the obligation period. DESNZ would receive processed data from Ofgem early the following month, which stated which measures had been approved and which required further clarification by energy suppliers. Under ECO4, DESNZ receives data on notified projects (including the household details) and on notified measures. Measures are marked as pending until the Project Reference Number has been provided and the measure has passed several checks and has been approved by Ofgem. The statistical release only includes measures with a Project Reference Number attached to obtain geographical information on where these measures have been installed. All figures are provisional until after the end of the ECO period and following Ofgem’s final compliance report for that period. Ofgem have six months after the end of each ECO period to produce their final compliance report, when all measure statuses should be finalised. For CSCO, as the ECO Help-to-Heat Order closed this obligation, Ofgem published their final compliance report for CSCO on 28 September 2017. However, suppliers could re-elect surplus measures out of CSCO after this date, up until 31 December 2018. 10 Household Energy Efficiency Methodology Note For ECO2, Ofgem published their ECO2 Final Determination Report on 11 April 2019, though suppliers could re-elect surplus measures out of ECO2 into ECO3 after this date. In the February 2022 quarterly release, BEIS (now DESNZ) revised the statistics to reflect the re-election of the ECO2 surplus actions to ECO3. There were around 82,000 ECO2 surplus actions approved by Ofgem. For ECO3, Ofgem published their ECO3 Final Determination Report on 9 February 2023, though suppliers could re-elect surplus measures out of ECO3 into ECO4 after this date. In the August 2024 quarterly release, DESNZ revised the statistics to reflect the re-election of the ECO3 surplus actions to ECO4. There were around 60,700 ECO3 surplus actions approved by Ofgem. The ECO measures figures in the statistical releases are based on the latest available information. Any measures which have been rejected by Ofgem or withdrawn by obligated energy suppliers have been excluded from the ECO measures reported. ECO Help-To-Heat measures have been reported from the June 2017 Household Energy Efficiency Headline Release. On 30 January 2017 BEIS (now DESNZ) at the time published the response to the ECO: Help to Heat consultation (which ran from 29th June 2016 to 17th August 2016). This covered the future ECO scheme, ECO2t, which followed the end of ECO 2 (on 31 March 2017). ECO3 measures have been reported from the February 2019 Household Energy Efficiency Headline Release. On 19 July 2018 BEIS (now DESNZ) published the response to the Energy Company Obligation, ECO3 2018 - 2022 consultation (which ran from 30 March 2018 to 29 April 2018). This covered the future of the ECO scheme, ECO3, which went live on 3 December 2018 and ran until March 2022. Measures installed from October 2018 were included in ECO3 and any excess measures from ECO Help-to-Heat could also be re-elected into ECO3. These re- elected measures were included under ECO3 from the February 2022 publication. ECO4 measures have been reported from the November 2022 Household Energy Efficiency Headline Release (indicative estimates based on data from Trustmark were reported in September and October 2022). On 20 July 2021 BEIS (now DESNZ) published a consultation on the Design of the Energy Company Obligation ECO4: 2022-2026. This covered the future of the ECO scheme, ECO4, and ran until 3 September 2021. The government response to the Energy Company Obligation (ECO4) consultation, published April 2022, sets out the policy of the scheme from April 2022 until March 2026. Measures installed from April 2022 were included in ECO4 and any excess measures from ECO3 could also be re-elected into ECO4. These re-elected measures were included under ECO4 from the August 2024 publication. In August 2025, DESNZ consulted on proposals to extend the ECO4 end date, as set out in Extending the ECO4 end date: consultation document. One of the policy decisions from that consultation was that ECO4 will be extended by nine months, ending on 31 December 2026, to allow suppliers additional time to meet existing targets and remediate non-compliant installations. 11 Household Energy Efficiency Methodology Note ECO households (headline and detailed release) The provisional number of households in receipt of ECO measures is calculated using the address information reported in the ECO measures data by energy companies. DESNZ use a de-duplication process (which strips out any non-alpha- numeric characters and upper-case letters) to estimate the number of unique properties in receipt of one or more ECO measures. DESNZ also presents information on ECO4 repeat households in the quarterly report (see definition below). The below text explains how these figures are calculated. Definitions: First-Time Households: ‘First-time’ households are households that have never installed a measure before under the respective ECO phase. ECO4 Repeat Households: ECO4 repeat households are households that have returned to install a measure under ECO4 (including ECO3 Interim) after having installed a measure (or measures) in earlier phases of the scheme. To calculate ECO4 repeat households, the number of ‘first-time’ households per month are calculated for ECO across all phases (ECOALL) and calculated separately for ECO4 to identify unique households in this phase. The ECOALL figure is then subtracted from the ECO4 figure on a monthly basis to provide an estimate of repeat households for that month. Note that the monthly figures for first-time households across all ECO phases are presented in Table 1.2. Consider an example using Household A. If ECO measure installations across the whole scheme (from January 2013) are considered, and Household A installed one measure in April 2013 (ECO1-2 phase) and one measure in April 2019 (during the ECO3 phase), it would only be considered a ‘first-time’ household in April 2013 as that is the first time it appeared in all ECO phases (ECOALL). However, if the ECO4 phase is taken in isolation, then Household A would be a ‘first-time’ household under ECO4 in April 2022 as that is the first time it installed an ECO4 measure. The difference between the April 2022 monthly figures for ECO4 and the April 2022 monthly figures across all ECO phases) are then the repeat households as if all ECO phases were considered, Household A would not appear as a ‘first-time’ household in the monthly figures in April 2022 but appears if only the ECO4 phase is considered. The formula is then as follows: ECO4 Repeat Households = ‘First-time’ ECO4 households’ monthly figure – ‘First-Time’ ECOALL households’ monthly figure ECO property characteristics (headline and detailed releases) Tables breaking down property type and tenure by obligation are based on the obligation of the first measure installed. There can only be one property type or tenure per household, so this ensures no double-counting occurs. Other ECO tables presenting the total number of ECO measures reflect all measures installed. For the 12 Household Energy Efficiency Methodology Note provisional number of households receiving ECO measures by tenure and ECO obligation, where ‘socially-rented’ has been recorded under Affordable Warmth measures installed, these are treated as “unknown” (as it is not possible for socially rented properties to benefit from measures delivered under Affordable Warmth). ECO Geographic breakdowns (headline and detailed releases) Provisional numbers of ECO measures installed by region, administrative area, and Parliamentary Constituency are available in the headline Accredited Official Statistics release. Provisional numbers of households in receipt of ECO measures by region, administrative area, and Parliamentary Constituency are available in the headline Accredited Official Statistics release. ECO measure types (headline and detailed releases) Tables breaking down ECO measures by type, include the following acronyms: • Standard CWI – Standard Cavity Wall Insulation • HTTC – Hard to Treat Cavity • Micro CHP - Micro Combined Heat and Power • DHS – District Heating System • District Heating: CHP upgrades – District Heating Combined Heat and Power upgrades • Solar PV - Solar Photovoltaic For external and internal wall insulation, where recorded under certain ECO phases, the reason for splitting by ‘built from 1967’ and ‘built pre-1967’ is due to building regulation changes in England and Wales (note that for Scotland this is pre and post 1965). From the 1960s, constructional changes have been caused primarily by amendments to regulations for the conservation of fuel and power, which have called for increasing levels of thermal insulation. Heating controls measures include the installation or upgrade of devices that enable households to better regulate space and water heating, such as programmers, room thermostats, thermostatic radiator valves, and smart or advanced control systems. For statistical reporting purposes, where multiple heating control components are installed at the same property as part of a single intervention or package and are recorded as the same control type, these are treated as one heating controls measure. Where different types of heating controls are installed at the same property (for example, a programmer alongside thermostatic radiator valves), each distinct control type is counted as a separate measure. This approach ensures consistency in measure counting while reflecting the range of control technologies installed. 13 Household Energy Efficiency Methodology Note ECO delivery costs (headline and detailed releases) DESNZ receives quarterly summary information from all obligated energy companies on their costs associated with delivering ECO. Delivery costs are defined as the cost of installing an ECO measure in a property. This includes the costs of technical monitoring, cost of assessment, costs involved with searching for ECO properties, installation costs and marketing costs by delivery partners involved with promoting the ECO obligations. These costs should include Value Added Tax (VAT) when it is not applicable for suppliers to claim this back from HMRC. These costs should not include those ordinarily associated with Green Deal (e.g., insurance-backed guarantees). Some costs may be estimated prior to the measure being fully installed or incurred prior to when the carbon or cost savings are reported. The aggregate delivery costs are historic costs and future costs may go up or down depending on a range of factors. Cost savings are based on all measures. In addition, administrative costs are collected from suppliers and include reporting and compliance, own marketing, and direct administrative costs (such as development of IT/reporting systems to support delivery of the scheme). The headline release presents the average price by obligation and the highest and lowest prices reported (upper and lower quartiles from ECO3 on) by suppliers for each obligation, where appropriate to show these. The suppliers have not been identified to protect commercial confidentiality. This shows that some energy suppliers are discharging their obligation more cost effectively than others. ECO Brokerage (discontinued series) The ECO Brokerage system operated as an anonymous auction, where providers could sell ‘lots’ of future measures of ECO Carbon Saving Obligation (now closed), ECO Carbon Saving Communities (now closed) and ECO Affordable Warmth, to energy companies in return for an ECO subsidy. The outcomes of each auction are publicly available, and the data are used without any adjustment. Until January 2021, these auctions occurred on a fortnightly basis. From February 2021, the auctions were held monthly. In May 2021, Crown Commercial Services (CCS) announced the decommissioning of the ECO brokerage mechanism in June 2021, with the final auction (Auction 205) occurring on 25th May 2021. Green Deal Assessments (discontinued series) The GD Assessment process A Green Deal Advisor would come to the property and use the Standard Assessment Procedure (SAP) to assess the energy and environmental performance of the property and produce an Energy Performance Certificate (EPC). This only needed to be done where a valid EPC had not already been completed. The Green Deal 14 Household Energy Efficiency Methodology Note Advisor would then carry out an Occupancy Assessment (OA) relating to the energy usage of the household. The Advisor would then ‘lodge’ the EPC and OA on the central register as a Green Deal Advice Report (GDAR). As stated in the Specification for GD Organisations,7 Advisors must have lodged the EPC and OA within two weeks of the assessment taking place. Once any measures have been installed in the property through a GD Finance Plan, then a final EPC would be lodged, showing the updated energy efficiency of the property with the new measures included. An Advisor could lodge an EPC or OA more than once – reflecting possible mistakes being corrected or a change in recommended measures. Green Deal Advice Reports (GDARs) were no longer considered by DESNZ to be an effective lead indicator of Green Deal Plans and their associated measures. Some stakeholders had significantly reduced the typical lead time between a GDAR being lodged and a Green Deal Plan going live, meaning that there was often little lag between these. GDARs were also used to facilitate access to some local energy efficiency schemes that began to reflect the majority of activity. It was therefore not possible to determine the share of GDARs that resulted in a Green Deal Plan and hence analyse the take up rate of households receiving Green Deal Finance relative to those who started the process. The publication of GDAR statistics ended in June 2018. Reporting GD Assessments (headline and detailed releases) NEC Software Solutions UK and EST Scotland provided DESNZ with a monthly extract from their EPC/GDAR registers, which included the underlying data from each EPC/OA for DESNZ to fully quality assure the data. Each property was counted only once to report the number of GD Assessments, and this was based on the first date when a GDAR was lodged. Any further analysis was based on the latest GDAR that was lodged for the given period in question. Therefore, the analysis for the headline release was based on EPC and OA data extracts for the latest period. An additional check was performed to ensure that each GDAR was only recorded once in either of the two national registers (one in England and Wales, and one in Scotland). If a GDAR was lodged in more than one register, then this was only counted once against the correct register based on the location of the property. The analysis for the detailed release was based on EPC and OA data extracts up to the end of the month following the end of each quarter (i.e., for the first quarter of 2016, January to March, extracts were taken up to the end of April). GDARs lodged 7 Point 6.14.1 https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/68627/003- 2012_Specification_for_Organisations_providing_the_Green_Deal_Advice_Service.pdf 15 Household Energy Efficiency Methodology Note in more than one register were removed (removing a very small level of double counting). For the coverage of the statistics to be up to the end of each quarter and to ensure there is no double counting, the following steps are taken: 1. 2. 3. Any GDARs lodged after the end of the quarter (i.e., for the first quarter of 2013, 31 March 2013) were removed using the OA lodgement date to identify these. Duplicates from the resulting file were identified using Unique Property Reference Number (UPRN) and removed so that only the latest GDAR lodged was included (i.e., by sorting in descending order using the “lodgement_date_time” variable). EPCs which relate to these GDARs were included in analysis. Any subsequent EPCs lodged, which do not have a GDAR lodged by the end of the quarter (i.e., for the first quarter of 2013, 31 March 2013), were not incorporated in this analysis. The further breakdowns presented in the detailed report were all based on the data provided in the data extract files and are outlined below. Property characteristics (detailed release) Information relating to the characteristics of properties getting GD Assessments was taken from the Energy Performance Certificate relating to the GD Assessment. Energy Efficiency Rating (detailed release) The Energy Efficiency Rating (EER) was presented in an A-G banding system for an Energy Performance Certificate, where Band A rating represents low energy costs (i.e., the most efficient band) and Band G rating represents high energy costs (the least efficient band). The EER bands based on SAP8 were: • Band A (92 plus) • Band B (81-91) • Band C (69-80) • Band D (55-68) • Band E (39-54) • Band F (21-38) • Band G (1-20) 8 Information on the Standard Assessment Procedure is here: https://www.gov.uk/standard- assessment-procedure 16 Household Energy Efficiency Methodology Note Property type (detailed release) Properties can be built in a large variety of configurations. A basic division is between free-standing or single-family houses and various types of attached or multi-user dwellings. Both sorts may vary greatly in scale and amount of accommodation provided. Many variations are purely matters of style rather than spatial arrangement or scale. A house or bungalow has a complete heat loss ground floor and a completely exposed roof. A dwelling without a heat loss floor cannot be a house and must be treated in the GD Assessment as a flat or maisonette. A flat or maisonette does not have both a heat loss ground floor and a heat loss roof. Reduced Standard Assessment Procedure (RdSAP) makes no distinction between a flat and a maisonette as regards calculations; it is acceptable to select either type as definitions vary across the UK. Built form (detailed release) All property types have a built form (not just houses). The four main types of build are detached, semi-detached, end-terrace and mid-terrace. Mid-terrace has external walls on two opposite sides (this category also includes any ‘Enclosed9 Mid-Terrace’ properties which have an external wall on one side only). End-terrace has three external walls (this category also includes any ‘Enclosed End- Terrace’ properties which have two adjacent external walls). Recommended measures (detailed release) The detailed statistical release reported the number of improvements by measures recommended in GDARs. These are the final recommendations an assessor will make to the household following an EPC and an Occupancy Assessment. Recommended improvements were listed in the Occupancy Assessment Technical Appendix, where further details about each of these measures could be found. See BRE GD OA Software (opens in new window) for more details. Green Deal Communities (discontinued series) Twenty-three Lead Local Authorities (covering a larger number of individual Local Authority areas, see table below) in England were allocated £85 million to help deliver energy efficiency improvements through a programme called Green Deal Communities. Local Authorities had flexibility in how they developed and delivered their own project locally and were encouraged to develop innovative solutions to drive demand (e.g., incentives, marketing, supply chain procurement, etc.). The focus of the programme was on delivering hard to treat energy efficiency measures and/or delivering in hard- 9 ‘Enclosed’ is typically applicable for ‘back-to-back’ terraces. 17 Household Energy Efficiency Methodology Note to-reach properties, predominantly but not limited to solid wall insulation. The scheme was to engage with and deliver to private households and private landlords, maximising local knowledge to identify appropriate property and support development of the supply chain locally where possible. Each Local Authority (LA) project lead was required to submit their data at designated interim points and again upon completion of the project, to enable effective evaluation of the programme approach and to inform future policy. This included a largely qualitative self-evaluation report to help understand each project area’s model of delivery, enabling understanding as to which approaches to delivery were found to be the most successful. In addition to this, Local Authorities were required to populate a quantitative data template, including data on Green Deal Assessments10 carried out and completed installations funded through the Green Deal Communities scheme. Interim data returns were submitted covering the period up until the end of January 2015 when most projects were still at an early stage of delivery. Areas subsequently submitted a second interim data return in 2016, covering the period up until the end of March 2016. Following that, areas submitted final data returns, covering the period up until the end of September 2016. Thorough quality assurance of the data was conducted by DESNZ, with figures verified by each lead LA. The final evaluation of the Green Deal Communities Programme (including final data returns) was published in March 2017. Interim estimates of the number of measures installed up to the end of March 2016 under Green Deal Communities were released in September 2016, with final estimates of measures installed up to the end of the scheme (end of September 2016) released in March 2017, following extensive data quality checks. 10 The total provisional number of Green Deal Assessments funded through the Green Deal Communities in all project areas is not currently available. 18 Household Energy Efficiency Methodology Note The following table is the full list of Local Authorities which form part of these projects: Area Name Ashfield Bath & North East Somerset Bracknell Bristol Consortium Broadland Consortium Cambridgeshire Dartford Consortium East Hampshire Consortium Eastleigh Consortium Leeds Consortium Haringey Consortium Harrow Lewisham Consortium Greater Manchester Participating Local Authorities Ashfield District Council Bath & North East Somerset Council Bracknell Forest Council Bristol City Council, North Somerset Council, South Gloucestershire Council Broadland District Council, South Norfolk Council, Norwich City Council Cambridge City Council, East Cambridgeshire District Council, Fenland District Council, Huntingdonshire District Council, South Cambridgeshire District Council, Cambridgeshire County Council Dartford Borough Council, Kent County Council, Sevenoaks District Council, Dover District Council East Hampshire District Council, Havant Borough Council Eastleigh Borough Council, Portsmouth City Council, Gosport Borough Council, Southampton City Council Leeds City Council, City of Bradford Metropolitan District Council, City of Wakefield Metropolitan District Council, City of York Council, Barnsley Metropolitan Borough Council, The Borough Council of Calderdale, Harrogate Borough Council, Kirklees Council, Selby District Council, Craven District Council, West Yorkshire Combined Authority London Borough of Haringey, London Borough of Camden, London Borough of Enfield, London Borough of Waltham Forest, London Borough of Islington, London Borough of Hackney London Borough of Harrow London Borough of Lewisham, London Borough of Bromley, London Borough of Bexley Bolton Council, Bury Council, Manchester City Council, Oldham Council, Rochdale Metropolitan Borough Council, Salford City Council, Stockport Metropolitan Borough Council, Tameside Metropolitan Borough Council, Trafford Council, Wigan Council Nottingham Nottingham City Council 19 Household Energy Efficiency Methodology Note Nuneaton & Bedworth Consortium Peterborough Plymouth South Buckinghamshire Consortium Suffolk Telford & Wrekin Woking and Surrey Consortium Worcestershire Nuneaton & Bedworth Borough Council, North Warwickshire Borough Council Peterborough City Council Plymouth City Council Aylesbury Vale District Council, Buckinghamshire County Council, Cherwell District Council, Chiltern District Council, Cotswold District Council, London Borough of Ealing, Milton Keynes Council, South Buckinghamshire District Council, South Oxfordshire District Council, Three Rivers District Council, Vale of White Horse District Council, Watford Borough Council, West Berkshire Council, West Oxfordshire District Council, Wycombe District Council Babergh District Council, Mid Suffolk District Council, Forest Heath District Council, St Edmundsbury Borough Council, Ipswich Borough Council, Suffolk Coastal District Council, Waveney District Council, Suffolk County Council Telford & Wrekin Council Epsom & Ewell Borough Council, Elmbridge Borough Council, Guildford Borough Council, Spelthorne Borough Council, Waverley Borough Council, Reigate & Banstead Borough Council, Mole Valley District Council, Tandridge District Council, Runnymede Borough Council, Surrey Heath Borough Council, Surrey County Council, Woking Borough Council Bromsgrove District Council, Malvern Hills District Council, Worcester City Council, Redditch Borough Council, Wyre Forest District Council, Wychavon District Council, Worcestershire County Council Green Deal Plans (headline and detailed releases) The Green Deal Plan process The Green Deal scheme has now been closed to new plans (installations and loans), though GD plans and measures statistics are still reported in the releases. Green Deal Plans are reported at different stages (see below for more detail), based on all potential Green Deal Plans that are or have been in the system. It was 20 Household Energy Efficiency Methodology Note expected that all Green Deal Plans have a Green Deal Advice Report (GDAR); although some more recent ‘new’ Green Deal Plans may not have had an Occupancy Assessment lodged on the EPC register (as there was a 14-day window in which this must occur). The data used comes from three sources – The Green Deal Central Charge Database and the NEC Software Solutions UK data (England & Wales) and Energy Savings Trust (Scotland). This allows verification checks that GD Measures are linked to a live or completed GD Plan. Three stage reporting of Green Deal Plans Uptake of the GD was below expectations and in July 2015 the Government announced there would be no further public investment in the scheme. The Framework to support the programme remained in place to service existing GD Plans and for any private finance providers wishing to enter the market. The Green Deal Finance Company – the vehicle created to finance GD loans and in which the Government ended public investment during 2015 – was purchased in January 2017 by new owners, who were offering new GD plans. For those choosing Green Deal Finance, there were three stages in the life cycle of a Green Deal Plan for which reports were generated using data received from the Central Charge Database: • the first stage (a ‘new’ Green Deal Plan) was after a customer has obtained a quote from a Green Deal Provider and confirmed they wished to proceed. The Green Deal Provider had then successfully requested a Green Deal Plan record prior to signature by the customer. It was possible that more than one Green Deal Plan may be requested for each household as the householder was able to request quotes from different Green Deal Providers. For statistical reporting purposes, only one Green Deal Plan per household was counted. • the second stage (a ‘pending’ Green Deal Plan) was when a Green Deal Plan had been signed by the customer, progress was being made to install Green Deal Plan measures and the Plan was being finalised so that charging could start. • the final stage (a ‘live’ Green Deal Plan) was after the measures had been installed in the property, the information required to disclose the Plan to future bill payers had been attached to the Plan and the energy supplier had all the information required to bill Green Deal charges. At this stage the daily charge had been confirmed along with the date from when the charge would be accrued on their electricity bill. The Central Charge Database provides the latest status of each Green Deal Plan. This includes where a plan was ‘Cancelled’ – which are not included in our reporting – and ‘Completed’ Green Deal Plans when a Plan has been fully paid off. In some cases, multiple Green Deal Plans have been recorded against an individual property. To ensure double counting does not take place only one Green Deal Plan 21 Household Energy Efficiency Methodology Note is counted against each unique property, with a Unique Property Reference Number being used to identify properties with more than one Green Deal Plan. The Green Deal Plan which is counted is the Plan at the furthest stage. For example, if a property has three Green Deal Plans recorded against it, one of which is ‘cancelled’, one of which is ‘new’ and one of which is ‘pending’, only the ‘pending is counted and the other two are disregarded. Equally, if there are multiple Plans at the ‘new’ stage, ‘pending’ stage, or ‘live’ stage, then only the one at the most advance stage is counted. The date at which GD Plans and measures are reported in these statistics is determined by the lodgement date of the post Green Deal installation EPC. Since the change of data supplier for England & Wales EPCs in September 2017, not all the EPCs are provided to DESNZ if a household opts out. In this scenario the measure will be counted if the GD Plan is live but will be classified based on the date in the GD Plan. Volumes of finance of Green Deal Plans (detailed release) The detailed release includes the estimated total initial loan amount associated with all ‘live’ and ‘completed’ Green Deal Plans. This is derived from the Green Deal Plan information found on the last page of the Energy Performance Certificate of the property. It is calculated using the daily charge multiplied by the length (in days) of the Plan. The daily charge is adjusted to remove the APR interest payment, which leaves just the ‘total initial loan amount’. Measures installed using Green Deal finance (detailed release) The Green Deal scheme has now been closed to new plans (installations and loans), though GD plans and measures statistics are still reported in the releases. The number of measures installed using Green Deal finance is based on data recorded on the Green Deal disclosure and information page of EPCs. These measures are reported against their month of installation. However, as the installation date of each individual measure is not known, the lodgement date of the post-installation EPC is used as a proxy. As stated above, since the change of data supplier for England & Wales EPCs in September 2017, not all the EPCs are provided to DESNZ if a household opts out. In this scenario the installation date will be classified based on the date of the GD Plan. Measures are only reported in the headline Accredited Official Statistics release if the associated Green Deal Plan for those measures has been recorded as ‘live’ on the Central Charge Database before the end of the latest month. Therefore, measures associated with Green Deal Plans which have subsequently been paid off (i.e., ‘completed’ Plans which are no longer ‘live’) will be included as measures installed using Green Deal finance. Measures are not included if they have been reported as “not installed” on the Green Deal disclosure and information page of EPC or if the paid-off date for that measure is before the Green Deal Plan became 22 Household Energy Efficiency Methodology Note live, or within a few months of that date. These are considered as system errors and therefore should not be included as measures installed using Green Deal finance. If a property has a ‘live’ and a ‘completed’ Plan, or multiple ‘live’ Plans, then only unique measures are counted (using the measures on the Plan with the latest EPC lodgement date). This is to ensure that there is no double-counting of measures installed using Green Deal finance. The number of measures installed using Green Deal finance in earlier installation months are subject to revision as Green Deal Plans may become 'live' after the month of installation. The number of measures installed using Green Deal finance in any month other than the latest month are not directly comparable with the number of ‘live’ Green Deal Plans for each of those respective months. This is because some measures may have been installed in a month prior to when the corresponding Green Deal Plan went ‘live’. Measures captured by administrative data sources (headline release) The total number of measures installed in properties through the Energy Company Obligation is presented on a monthly basis with the same lag as with ECO measures to ensure completeness of data across the delivery mechanisms. This does not include measures installed but not captured by administrative data sources. A small number of these properties have had measures installed through more than one delivery mechanism and there is therefore a small level of double counting. The number of measures installed through Green Deal Finance are based on the latest complete quarterly data. These will be updated on a quarterly basis (February, May, August, and November) in the headline release. Households that have had measures installed and captured by administrative data sources (headline release) The number of individual households with measures installed through the Energy Company Obligation is presented monthly with the same one-month lag as with ECO measures to ensure completeness of data across the delivery mechanisms. A small number of these properties have had measures installed through more than one delivery mechanism and there is therefore a small level of double counting. Where a household has measures installed in two or more months, the earliest installation month is recorded. The number of households with measures installed through Green Deal Finance Plans are based on the latest complete quarterly data. 23 Household Energy Efficiency Methodology Note Green Deal Home Improvement Fund (discontinued series) On 23 July 2015 DECC announced that there will be no future funding releases of the Green Deal Home Improvement Fund. GDHIF closed for applications on 30 September 2015, and at the end of June 2016 the scheme closed. GDHIF was an incentive scheme open to all householders in England and Wales wanting to improve the energy efficiency of their homes. The scheme allowed householders to choose one or both of two offers and they were eligible to claim up to £7,600. Householders could also claim a refund of up to £100 for a Green Deal Advice Report (GDAR). GDHIF release 1 closed to new applicants at 6:30pm on 24 July 2014. GDHIF release 2 commenced on 10 December 2014 and GDHIF release 3 commenced on 16 March 2015. For more information, please see the GDHIF website. For more information on the separate scheme that operated in Scotland please see the relevant website. GDHIF application release 1 data were published on the gov.uk website on a weekly basis until the scheme closed, to assist businesses and households. This weekly series reported the number of applications, vouchers issued, and maximum value of vouchers issued. Also included on a weekly basis from 17 December 2014 until 7 January 2015 (on the same website) were GDHIF application statistics on GDHIF release 2. A one-off publication was made on 12 December to show that funding allocated to Solid Wall Insulation applications reached its maximum allocation amount. Also included on a weekly basis from 24 March 2015 (on the same website) were GDHIF application statistics on GDHIF release 3. A one-off publication was made on 26 March 2015 to show that funding allocated to Solid Wall Insulation applications reached its maximum allocation amount. A GDHIF issued voucher (following an application) could be for one or more measure for any given property. In a small number of cases more than one voucher was paid per household. The headline release reports the absolute numbers for GDHIF vouchers paid, their associated value and measures installed through GDHIF, based on record-level data from the GDHIF Administrator. Also reported are the number of GDHIF applicants that had received a Green Deal Assessment Report (GDAR) refund (of up to £100 each) and/or received the Home Buyer Bonus (of up to £500 each). However, the number of GDHIF active applications11 and vouchers issued12 and associated budget committed are only reported at an aggregate level as the same level of disaggregation in that data was not received. The detailed report includes the number of unique households in receipt of GDHIF measures by region, administrative area, Parliamentary Constituency, and tenure. Geographic locations of properties receiving GDHIF payments are taken from application data and details on the Energy Performance Certificate (EPC) of the 11 GDHIF active applications include any vouchers issued, pending, or vouchers which have been paid. It excludes any vouchers which have been cancelled, rejected, superseded or claim failed. Vouchers issued are reported against the month in which they were issued. 12 There may have been several vouchers issued for a single application where a customer has modified key elements of their application. 24 Household Energy Efficiency Methodology Note property. The tenure of the householders of these properties is taken from EPC data, unless this data is missing, in which case the tenure is taken from the GDHIF application data. Upgrading one million homes target, (May 2015 – April 2020) (discontinued series as target period finished) Until September 2017, the Statistical Release reported on the one million homes target set for the 2015 Fixed term Parliament, which was due to run until April 2020. Reporting was revised in December 2017 to reflect the Government’s manifesto commitment on home energy efficiency and the Clean Growth Strategy published in October 2017.13 Reporting is still set-in terms of upgrading around one million homes through the Energy Company Obligation (ECO) and other Government domestic energy efficiency schemes. The difference, however, is that all measures (for example insulation and heating measures) available under those schemes are included when previously only insulation measures were included. The period covered is the same five years as before, from the start of May 2015 through until the end of April 2020. The ECO and Green Deal framework consist