UK S.I. 2022/875: ECO4 Solar PV & Energy Efficiency Order Guide
Updated 6 September 2026 · By SolarNevs Research Desk, Dealer surveys + verified sources · 1 source · Method ↗
Key Takeaways
- The Electricity and Gas (Energy Company Obligation) Order 2022 (S.I. 2022/875) governs the ECO4 obligation phase running through 31st March 2026.
- Enacted under Section 33BC of the Gas Act 1986, Section 27A of the Electricity Act 1989, and Section 103A of the Utilities Act 2000.
- Article 50 enforces minimum SAP band jumps: homes starting in Band D or E must achieve Band A, B, or C; homes starting in Band F or G must reach Band A, B, C, or D.
- Mandates heating performance to achieve 21 degrees Celsius in main living areas and 18 degrees Celsius in secondary areas.
- Requires all measures to comply with PAS 2035:2019 and undergo verification via the TrustMark Data Warehouse under Ofgem administration.
Statutory Authority & Scope of ECO4
The Electricity and Gas (Energy Company Obligation) Order 2022 (S.I. 2022/875) sets binding energy efficiency obligations for licensed electricity and gas suppliers across Great Britain.
Administered by the Gas and Electricity Markets Authority (Ofgem), ECO4 focuses on deep multi-measure retrofits for fuel-poor and inefficient domestic properties through 31st March 2026.
Article 50 Minimum SAP Energy Efficiency Improvements
Under Article 50 of S.I. 2022/875, energy suppliers cannot claim partial measures unless the whole-house project achieves defined Standard Assessment Procedure (SAP) rating upgrades:
Starting EPC / SAP Baseline | Mandatory Post-Project SAP Band Target | Statutory Clause |
|---|---|---|
Pre-project Band D or E | Must achieve Post-Project SAP Band A, B or C | S.I. 2022/875 Article 50(2)(a) |
Pre-project Band F or G | Must achieve Post-Project SAP Band A, B, C or D | S.I. 2022/875 Article 50(2)(b) |
Space Heating Standard | Heated to 21 degrees Celsius in living areas, 18 degrees Celsius elsewhere | S.I. 2022/875 Article 2 |
Solar PV measures deployed under ECO4 are typically paired with insulation and heat pumps to satisfy these mandatory band transitions.
PAS 2035 Retrofit Standards & TrustMark Quality Oversight
To ensure technical quality and consumer protection, S.I. 2022/875 embeds strict operational standards:
- PAS 2035:2019 Compliance: Retrofits must be overseen by a qualified Retrofit Coordinator following Publicly Available Specification 2035:2019.
- TrustMark Data Warehouse: Installers must be TrustMark-registered, and all completed measures must be formally lodged in the TrustMark Data Warehouse repository.
- Ofgem Verification: The Administrator audits project lodgements to verify genuine reductions in household energy expenditure.
Frequently asked questions
What is the statutory basis of the ECO4 scheme under UK law?
The scheme is established under S.I. 2022/875 (The Electricity and Gas (Energy Company Obligation) Order 2022) pursuant to Section 33BC of the Gas Act 1986, Section 27A of the Electricity Act 1989, and Section 103A of the Utilities Act 2000 (August 2026).
What are the Article 50 minimum SAP band improvement requirements?
Under Article 50, if pre-project SAP is Band D or E, post-project SAP must reach Band A, B, or C; if pre-project SAP is Band F or G, post-project SAP must reach Band A, B, C, or D (August 2026).
What internal heating comfort standards must ECO4 projects achieve?
Heating measures must achieve a reduction in heating costs while heating premises to **21 degrees Celsius** in main living areas and **18 degrees Celsius** in all other areas (August 2026).
What retrofit quality standard governs ECO4 solar installations?
All retrofit installations must comply with PAS 2035:2019 standards and be lodged in the TrustMark Data Warehouse (August 2026).
References
- UK Legislation: S.I. 2022/875 — accessed 31 August 2026
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