«Methodology note accompanying headline and detailed National Statistics releases on the domestic Green Deal, Energy Company Obligation and Home ...»
Methodology note accompanying headline and detailed National Statistics
releases on the domestic Green Deal, Energy Company Obligation and Home
Insulation Levels in Great Britain.
17 September 2015
Methodology note accompanying headline and detailed National Statistics releases on
the domestic Green Deal, Energy Company Obligation and Home Insulation Levels in
This note summarises the methodology used to produce estimates published in the headline and detailed National Statistics releases on the domestic Green Deal (GD) and Energy Company Obligation (ECO). It also summarises the methodology used to estimate the levels of home insulation in Great Britain, which is published in the regular detailed releases.
This methodology note is intended to help users understand the assumptions made in the compilation of these statistics and some of the limitations of the data sources.
This methodology note is regularly reviewed and updated to reflect additions, and changes to the reporting of the headline and detailed National Statistic series.
The statistics related to this methodology note have been assessed by the UK Statistics Authority against the Code of Practice for National Statistics. The Statistics Authority published
its report on 12 June 2014:
The Statistics Authority has determined that these statistics can be designated as National Statistics following the implementation of a number of actions detailed in this methodology note (first addressed in the methodology note released on 23 September 2014). This includes documentation on the needs of users, improving methodology on assumptions, assessing risks to use of admin data, improving clarity and linkages between the range of statistics produced and review data release formats.
© Crown copyright 2015 You may re-use this information (not including logos) free of charge in any format or medium, under the terms of the Open Government Licence.
To view this licence, visit www.nationalarchives.gov.uk/doc/open-government-licence/ or write to the Information Policy Team, The National Archives, Kew, London TW9 4DU, or email: firstname.lastname@example.org.
Any enquiries or comments in relation to this statistical release should be sent to DECC’s Green Deal Statistics Team at the following email address: EnergyEfficiency.Stats@decc.gsi.gov.uk Contact telephone: 0300 068 5106
This document is also available from our website at:
https://www.gov.uk/government/collections/green-deal-and-energy-company-obligation-ecostatistics Contents Summary of data sources
Data quality of data sources
Landmark / Energy Savings Trust Scotland (EST)
Green Deal Central Charge Database
Green Deal Oversight and Regulation Body
Users/uses of the report
Green Deal Assessments
The GD Assessment process
Reporting GD Assessments (headline and detailed releases)
Property characteristics (detailed release)
Energy Efficiency Rating (detailed release)
Property type (detailed release)
Built form (detailed release)
Recommended measures (detailed release)
Pioneer Places (detailed release)
Core Cities (detailed release)
Green Deal Communities (detailed release)
Green Deal Plans (headline and detailed releases)
The Green Deal Plan process
Three stage reporting of Green Deal Plans
Geographic breakdowns of Green Deal Plans (detailed release)
Volumes of finance of Green Deal Plans (detailed release)
Measures installed using Green Deal finance (headline release)
Measures captured by administrative data sources (headline release)
Households that have had measures installed and captured by administrative data sources (headline release)
Measures not captured by administrative data sources (detailed release)
Background and Methodology
Finance method as reported by householder
Caveats and concerns
The number of measures installed with an accompanying GDAR
Cashback (headline and detailed releases)
Green Deal Home Improvement Fund (headline and detailed release)
ECO households (headline and detailed releases)
ECO measures (headline and detailed releases)
ECO property characteristics (detailed release)
ECO measure types (headline release)
ECO delivery costs (detailed release)
Individual households that have had measures installed – Coalition government 1 million homes target (headline release)
Insulating 1 million homes – Conservative government target - (headline release)................. 28 Households with at least one usual resident (detailed releases)
ECO Brokerage (headline and detailed releases)
Estimating carbon and energy savings (detailed releases)
Estimating carbon and energy savings for ECO measures
Estimating carbon savings for GD Cashback measures
Additionality of Cashback
Multiple Cashback measures
Accounting for missing values
Estimating annual energy saving for GD Cashback measures
Estimating annual energy saving for Green Deal Home Improvement Fund (GDHIF) measures
Estimating annual carbon savings at household level
Disaggregating Carbon Savings and Energy Savings
Additionally of GDHIF
Estimating annual energy saving for GD Plan measures
The supply chain (headline and detailed releases)
Home Insulation Levels in Great Britain (detailed releases)
Summary of overall approach
Cavity wall insulation
Solid wall insulation
Sources of increase in insulation levels
Further information and feedback
Summary of data sources The estimates use administrative data generated as part of the Green Deal and Energy Company Obligation processes. In addition, the estimates of home insulation levels use data contained within the national housing surveys and published by the Department for Communities and Local Government to build up an overall picture of the housing stock in Great Britain.
There are a number of sources of administrative data used to produce these statistics – each
report will state which sources have been used, based on the content being included:
Landmark – who manage the national lodgement of Green Deal Assessments in England and Wales Energy Savings Trust Scotland (EST) – who manage the national lodgement of Green Deal Assessments in Scotland Green Deal Central Charge Database – which manages the recording and administration of Green Deal Plans Ofgem – who administer the Energy Company Obligation (ECO) and collect information from energy companies on measures installed under ECO.
The Green Deal Oversight and Regulation Body (ORB) – who administer the certification of GD organisations (including assessors, installers and providers) Data on ECO brokerage is publically available following each auction.
Capita – who administer the Green Deal Cashback Scheme and the Green Deal Home Improvement Fund Energy Savings Trust (EST) – who run the telephone Energy Saving Advice Service (ESAS) offering impartial energy-saving advice to homes in England and Wales National housing surveys – which collect data on the housing stock in England, Wales and Scotland Department for Communities and Local Government (DCLG) – 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 After appropriate quality assurance, DECC uses the data from these data sources to produce the headline and detailed estimates included in National 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 National Statistics releases.
In addition, the statistics on insulation levels which make use of National Statistics from national housing surveys/other data sources rely on the data quality assurance processes as published by the producing departments.
Data quality of data sources The administrative data sources listed on Page 6 are all subject to a range of data quality checks employed by both data providers and DECC to ensure that data are as fit for purpose as
possible. These checks are summarised below:
Landmark / Energy Savings Trust Scotland (EST) Landmark manages the Energy Performance of Buildings Register and GDAR register in England and Wales, and Energy Savings Trust Scotland (EST) – manage the equivalent registers for Scotland properties.
The data quality of Energy Performance Certificates (EPC) is governed by DCLG, who issued revised Scheme Operating Requirements (SORs) for producers of EPCs. These requirements, effective from 1 July 2012 are to be implemented by ALL Certification Bodies to ensure and maintain consistency.
The revised SORs set out the audit and associated requirements for Energy Assessors. All assessors must sign up to the code of conduct. SORs describe actions all schemes must take if Code of Conduct failures are revealed during Quality Assurance activity.
In addition, all Accreditation Schemes are regularly audited by independent auditors, appointed by DCLG against SORs to make sure that they work to a minimum standard. Failure to comply with SORs will result in corrective measures imposed on them in form of Disciplinary Notices and may result in eventual withdrawal of Secretary of State approval to operate as an Accreditation Scheme.
All assessors must declare complaints received from customers and others to the scheme or schemes, who will be obliged to investigate.
A minimum of 2% of all EPCs will be randomly selected for audit. In addition:
- All assessors will be subject to a minimum check of 1 EPC or Display Energy Certificate (DEC) per 6 months (unless no certificates have been lodged within that 6 month period);
- All new registrants will be assessed within 30 days of joining the scheme, or if no certificates issued within the 30 day period the first certificate will be assessed;
Assessors must provide the information requested within 3 working weeks of the request or have a clear reason for not complying with the request. Any energy assessor who fails to provide complete information will be suspended by their scheme.
Any audit failures should be judged to be correct if the absolute rating is either 5% of the rating calculated by the Quality Assurance (QA) Audits or within 5 absolute points. Any DECs that fail an audit will be replaced. It will also trigger a request for a further two certificates to be submitted for audit. There will be a charge for each additional QA check required subject, within reason, to the level of complexity.
If either of the additional certificates fails its QA checks the energy assessor must be suspended or asked to complete further training.
Accreditation bodies are also required to impose additional QA audits for other reasons including, excessive use of helpdesks, complaints from clients, high lodgements or "where a scheme forms a view, for whatever reason, that a particular energy assessor may be at high risk of providing an erroneous certificate, the auditing of an energy assessors work should be brought forward to the next available certificate, and depending on the level of risk the sampling rate of that persons work should be increased".
Energy Assessors can be suspended or removed from the scheme at any time for failing a QA audit, typically for not supplying requested audit information, transgression of the code of conduct, failing to replace an EPC, DEC or Advisory/Recommendation report when requested to do so, or as the result of an upheld complaint, in such cases the notice of suspension or removal from a scheme is required to be sent to all other scheme operators and DCLG.
Summary of evidence required for QA audits of EPCs include: