UK guidance on regulatory requirements under the Great British Insulation Scheme (GBIS) in the United Kingdom.

This page provides formal guidance on the regulatory framework governing the Great British Insulation Scheme (GBIS). It is intended for energy suppliers, registered installers, local authorities, and property owners seeking to understand the operational, technical, and compliance standards mandated under the scheme.

The GBIS is a government-backed energy efficiency programme introduced in 2023 to support cost-effective insulation measures across eligible UK households. It is regulated by the Department for Energy Security and Net Zero (DESNZ) and administered by Ofgem (Office of Gas and Electricity Markets) in accordance with statutory powers.

The GBIS operates under the Energy Company Obligation (ECO) Amendment Regulations, specifically designed to expand access to insulation support. It is a statutory obligation for major energy suppliers to deliver insulation improvements under defined eligibility and delivery rules.

Key legislation includes:

  • Electricity and Gas (Energy Company Obligation) Order 2022 (as amended)
  • Supplementary guidance issued by Ofgem, updated regularly

Compliance with GBIS is mandatory for obligated suppliers and regulated installers, and subject to ongoing monitoring and auditing by Ofgem.

Scheme Objective and Scope

The GBIS focuses on single insulation measures to deliver immediate improvements in domestic energy efficiency.

Core objectives include:

  • Reducing household energy bills
  • Improving housing thermal performance
  • Supporting low-income and middle-income households in EPC D–G rated homes
⚠️ ECO4 has closed to new applications — here’s the help you can get nowECO4 grants are no longer available. See the grants and funding you can get now.

Unlike the multi-measure ECO4 scheme, GBIS delivers one primary insulation improvement per property.

Regulatory Delivery Categories

The scheme is divided into two delivery groups, each with distinct regulatory rules:

1. Low-Income Eligibility Group (Core Group)

To be treated under this group, households must:

  • Receive a qualifying means-tested benefit (e.g. Universal Credit, Pension Credit)
  • Occupy a property with an EPC rating of D, E, F or G
  • Reside in properties suitable for the proposed insulation

2. General Eligibility Group (Standard Group)

This group is defined by property characteristics, not benefit entitlement:

  • Homes must fall within council tax bands A–D in England (A–E in Scotland and Wales)
  • EPC rating must be D, E, F or G
  • Properties must not have received previous energy upgrades under overlapping schemes

 

All eligibility claims must be supported by verifiable documentation at point of submission.

Technical and Installation Standards

Installers must comply with strict technical requirements to ensure measure quality, occupant safety, and scheme legitimacy.

All works must meet:

  • PAS 2035:2019 – Specification for whole-house or whole-building energy retrofit
  • TrustMark registration – Government-endorsed quality assurance scheme
  • Building Regulations 2010 (England and Wales) or equivalent local standards (Scotland and Northern Ireland)

Insulation types regulated under GBIS:

  • Loft insulation
  • Cavity wall insulation
  • Solid wall insulation (internal or external)
  • Flat or pitched roof insulation
  • Underfloor insulation

All materials and methods must be installed in accordance with manufacturer instructions, PAS standards, and Ofgem delivery rules.

Reporting and Monitoring Requirements

All GBIS activity must be reported by obligated suppliers to Ofgem using prescribed digital reporting formats. These reports must include:

  • Customer eligibility evidence
  • Property EPC documentation
  • Installers’ certification and compliance records
  • Pre- and post-installation photographic evidence
  • Signed customer declarations

Installations may be subject to post-installation inspections or random audits. Non-compliance may result in rejection of claimed measures or enforcement action.

Supplier and Installer Obligations

Obligated Energy Suppliers Must:

  • Identify eligible households and offer them support
  • Contract with certified installers only
  • Ensure all measures comply with GBIS scheme rules
  • Submit timely and accurate reports to Ofgem
  • Resolve delivery failures or disputes through approved resolution processes

Installers Must:

  • Hold current TrustMark registration
  • Conduct pre-installation surveys
  • Deliver measures in compliance with PAS 2035 and other technical standards
  • Retain records for audit purposes
  • Adhere to the Code of Conduct for energy efficiency works

Enforcement and Compliance

Ofgem serves as the scheme administrator and regulatory enforcer. It holds authority to:

  • Review supplier submissions
  • Investigate irregularities or suspected fraud
  • Withhold or revoke delivery credit for non-compliant installations
  • Impose financial penalties for systemic breaches
  • Suppliers and installers must maintain accurate, retrievable records for at least six years after the completion of works.

For organisations and individuals working within the GBIS scheme:

  1. Review the latest statutory guidance published by Ofgem relating to GBIS delivery requirements.
  2. Ensure installer accreditation via TrustMark and PAS 2035 certification.
  3. Use standardised documentation to record eligibility, installation, and post-installation verification.
  4. Submit accurate and timely reports to Ofgem via approved channels.
  5. Maintain all records for auditing purposes and ensure staff are trained in data and compliance management.