What is GBIS? A summary for installers

What is ECO+

GBIS was announced by the Chancellor on 23 September as part of the Growth Plan 2022, confirming £1bn of help through the scheme between April 2023 and March 2026.

Formerly known as ECO+, the scheme is now known as the Great British Insulation Scheme, but follows the same guidelines as ECO+.

A core aim of GBIS is to reach a large number of households and deliver a high number of energy efficiency measures as quickly as possible.

GBIS will deliver mainly single, low-cost insulation measures to households rather than multiple measures.

This will ensure the maximum number of households can receive support through the scheme as quickly as possible.

The eligibility will be divided into two groups:

Broader group

Households who are not eligible for support under other ECO schemes. This group will cover all homes in Council Tax bands A-D in England, A-E in Scotland and A-C in Wales, with an EPC of D and below.

Low-income group

Households that would qualify via the usual ECO4 qualifying criteria.

While GBIS will focus on owner-occupied homes, it will also support inefficient social housing and private rented housing subject to some restrictions.

GBIS follows the infill rules of ECO4 allowing neighbouring properties to qualify at set ratios.

Broader eligibility group

By including this broader eligibility group, GBIS will help bridge the current gap in support for these households and allow more cost-effective delivery of measures to a larger volume of homes through reduced search costs.

This group will cover all homes in Council Tax bands A-D in England, A-E in Scotland and A-C in Wales, with an EPC of D and below.

Council tax banding is being used as a proxy for income or other eligibility criteria do not apply.

Low income group

The second group of households will cover low-income households, mirroring ECO4 eligibility.

Government intends for a minimum of 20% of the GBIS annual spend to be targeted at the low-income eligibility group.

Households in this group are those who are considered more likely to be at risk from struggling to pay their energy bills, but would otherwise be ineligible for support through other schemes.

The eligible benefits are the same as in ECO4.

However, we do propose several changes to the low-income eligibility criteria to distinguish the group from households that receive support under ECO4.

Where a property in the low-income eligibility group has a starting EPC band of E, F or G, it must be demonstrated that the property cannot meet the ECO4 minimum energy efficiency improvement requirement - this reduces competition with the delivery of ECO4.

Or that the property is only eligible for a single insulation measure and heating controls.

Therefore, the preferred proposal is to use the same exemption criteria to evidence that a property cannot meet the ECO4 Minimum Requirement and allow these to be treated under GBIS.

Homes in Band E, F and G will only be eligible for GBIS where the ECO4 minimum requirement cannot be met.

Flex for low income group

Under LA and Supplier Flex, a local authority or participating supplier 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.

Suppliers have the option to work independently from local authorities and refer households based entirely on their own debt data as long as each referred household falls into a proxy referral category, such as homes in receipt of Council Tax reduction.

The Government intends to increase the cap on LA and Supplier Flex delivery to up to 80% of a supplier’s low-income minimum.

For the general eligibility group, private renting households will only be able to receive higher-cost measures that are more likely to be delivered with a customer contribution from the landlord through the scheme. They will therefore not be eligible for loft or cavity wall insulation, as these are less likely to require a customer contribution from the landlord.

Private rented homes will be eligible for all other insulation measures including solid wall, pitched roof, flat roof, under floor, solid floor, park home and room-in-roof insulation, however those in EPC bands F and G will be excluded in the low income group.

Social housing

Social housing in the general group must be a household in Council Tax bands A-D in England, A-E in Scotland and A-C in Wales to be eligible for GBIS.

Only EPC bands E, F and G will be eligible whilst households in EPC band D will be limited to Innovation Measures.

As with owner-occupier households, these homes in Band E, F or G will only be eligible for GBIS where the ECO4 minimum requirement cannot be met.

Social housing tenants are eligible to receive any single insulation measure but not heating control - this is because social housing landlords are expected to provide a functioning heating system to their tenants and to avoid duplication with other support, such as the Social Housing Decarbonisation Fund.

How GBIS fits with existing schemes

Existing government schemes, including ECO4, are multi-measure schemes that seek to treat a whole house in line with industry best practice, and to prepare homes adequately for low-carbon heating technologies.

They are all also focused solely on those on low incomes, least able to pay and in fuel poverty.

In contrast, GBIS is designed to be a mainly single measure scheme, focusing on installing the most cost-effective measures to achieve bill savings in as many homes as possible.

Blending funding schemes is likely to be disallowed.


GBIS will continue a ‘fabric-first approach’ and heat generating measures are not eligible under the scheme.

Under GBIS, both the general and low-income group will be eligible for the following insulation measures:

  • Cavity wall insulation
  • Solid wall insulation (both external and internal)
  • Loft insulation
  • Pitched roof insulation
  • Flat roof insulation
  • Under floor insulation
  • Solid floor insulation
  • Park home insulation
  • Room-in-roof insulation

Each household in both eligibility groups will be able to receive one single insulation measure through the scheme.

If a low-income home requires multiple measures, we would expect it to receive support through ECO4 as opposed to GBIS.

GBIS will offer heating controls as a secondary measure for the low-income eligibility group only.

This will only be available to owner-occupier households to prevent duplication with other schemes and requirements in place for other tenancy types.

GBIS will not deliver add-on heating controls, such as Time and Temperature Zone Control, Weather Compensation Controls, and Smart Heating Controls.

It is intended that the provision of smart meter advice be a mandatory requirement alongside the retrofit advice as required under the TrustMark Licence Plus standards.

Customer contributions

While both eligibility groups can choose to provide a customer contribution for a higher-cost measure, the Government recognise for many low-income group households this will not be possible, therefore this group will be more likely to receive loft or cavity insulation.

As such, we expect the majority of higher-cost measures with a customer contribution to be delivered to the general eligibility group - an estimated 8.3m households in Great Britain.


GBIS does not intend to set any minimum requirements to improve the EPC band of a home.

With the focus on mainly single, low-cost insulation measures (plus the option of heating controls as secondary measures for low-income households), it is less likely that a household will be improved by a set number of EPC bands.

As the objective of GBIS is to deliver high volumes of single measures at pace, the Government propose to adopt the ECO4 scoring approach, but with ECO+ eligible measures receiving ECO4 Partial Project Scores without the 20% deflator that would usually be applied.

A pre-retrofit assessment of a property’s SAP band will be required either through an RdSAP (reduced data SAP) assessment or an EPC. A post-retrofit assessment for GBIS would not be required.

ECO4 annual bill savings are determined by modelling each measure in isolation to work out the annual bill savings, when in reality there is an interaction between measure savings when they are installed as part of multi-measure projects - as a result potential savings are overestimated.

To account for this, Ofgem will apply a score correction deflator of 10% to all Partial Project Scores - except for when heating controls are applied.

The scheme intends for the starting SAP rating to be evidenced by an existing valid pre-installation EPC, or an EPC/RdSAP assessment undertaken as part of the PAS2030/2035 or TrustMark Licence Plus pre-installation requirements.

As we are not setting minimum score improvement requirements or requiring full project scores, we do not intend to require a post-installation RdSAP assessment or EPC for GBIS.

We propose retaining the 10% uplift that is applied to projects that are delivered under Route 4 of the flexible eligibility mechanism for GBIS - this will only apply to measures delivered to households within the low-income group.

Guarantees and accreditations

The scheme will continue to require guarantees under GBIS.

We intend to mirror ECO4 requirements for all ECO installers to be TrustMark registered.


The Government has responded to the consultation and re-brand to BIS here.

Read the consultation here.

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