Great British Insulation Scheme

What to know first

Here are the most important points to understand before using this guide.

Is this guide still useful to you?

Yes, if you had GBIS work, made an application before the scheme closed, are checking old paperwork, or want to compare current support. It cannot tell you whether a new measure suits your home. That needs a property-specific assessment, and any live support scheme will apply its own rules.

Introduction

The Great British Insulation Scheme, usually shortened to GBIS, was a government energy-efficiency scheme for homes in Great Britain. It applied in England, Scotland and Wales. It did not apply in Northern Ireland.

GBIS ended on 31 March 2026. New applications and new GBIS installations are no longer available. Suppliers, Ofgem, TrustMark and other bodies may still be processing records, monitoring work, handling complaints or arranging remediation connected with installations completed while the scheme was running.

The scheme is still worth understanding. Its rules explain why some households received one insulation measure, why others were asked to contribute, and which documents should exist. They also help you recognise whether a current contact is about genuine follow-up work or is wrongly presenting GBIS as a live grant.

This guide provides general information. It is not a survey, retrofit design, grant decision or legal assessment. A current provider must assess your home and apply the rules of any scheme that is open now.

The table below gives the current position at a glance.

How did GBIS work?

GBIS was not a cash payment made directly to a homeowner or tenant. It placed a legal obligation on medium and large energy suppliers. Suppliers met that obligation by funding qualifying energy-efficiency measures, usually through installers and other delivery partners.

That structure matters because the supplier chose which projects to support and how much funding to offer. A household could appear to meet the published rules but still receive no offer. The property could be unsuitable, the proposed measure could cost too much within the supplier model, or delivery capacity could be limited.

The scheme had a general eligibility group and a low-income group. Local authority and supplier Flexible Eligibility routes widened access for some households. A retrofit assessment then considered the building and the proposed measure before an installation could proceed.

What do the latest delivery figures show?

The Department for Energy Security and Net Zero published provisional figures in June 2026 covering installations completed by the scheme end. They recorded 139,100 measures in 100,900 households. Most households received one measure, although some received linked controls or, after rule changes, two primary measures.

Around 74,200 measures, or 53% of the total, were delivered to the low-income group. About 11,600 of those measures used the Flexible Eligibility route. Cavity wall insulation, loft insulation and heating controls made up most recorded delivery.

These are administrative statistics based on measures recorded by Ofgem. They show the scale and mix of delivery, but they do not prove that every installation performed well or predict the saving achieved in an individual home. The figures remain provisional while validation and revisions continue.

Who is this guide for?

This guide is for homeowners, private tenants, landlords and social housing residents who want to understand how GBIS worked. It is particularly useful if you had insulation fitted, are trying to identify an installer, have questions about a contribution, or need to raise a concern about workmanship.

It is also for people looking for help with insulation now. The comparison section explains current routes in England, Scotland and Wales, including the important limits that apply to each one.

What this guide covers

The guide explains:

• why GBIS was introduced and how the supplier obligation worked;

• the historic general, low-income and Flex eligibility routes;

• the insulation measures and linked controls that were covered;

• why funding and household contributions varied;

• how to check an old application, installation or scheme record;

• what assessment, installation and handover should have involved;

• how GBIS compares with current national and local support;

• consumer rights, complaint routes and wall-insulation remediation;

• how to recognise and report misleading or fraudulent contact; and

• where to find official information and practical support.

Why the scheme was introduced

GBIS was developed during a period of high energy prices and renewed concern about the efficiency of Great Britain's housing stock. Many homes lose significant heat through roofs, walls and floors. Improving the building fabric can reduce the amount of energy needed to maintain a comfortable temperature, although the result varies by property and how it is used.

The policy problem was not simply a lack of insulation products. Upfront costs, uncertainty about suitable work, split incentives between landlords and tenants, and long payback periods can all discourage households from acting. Government used a supplier obligation to direct support towards less efficient homes without relying on a single cash-grant application model.

The policy and household aims

At household level, GBIS was intended to make selected insulation work free or cheaper. The wider policy aims were to reduce heating demand, support households at greater risk of fuel poverty, improve energy security and contribute to emissions reduction.

In practical terms, the scheme aimed to:

• reduce heat loss from eligible homes;

• lower modelled heating costs where measures performed as intended;

• improve comfort in homes that were difficult to keep warm;

• extend support beyond the narrowest means-tested group;

• direct a substantial share of delivery to low-income households; and

• increase the rate of straightforward insulation installation.

The low-income requirement was not incidental. Scheme rules required suppliers to deliver a minimum share of their obligation to that group. Latest provisional statistics show that 53% of measures were recorded in the low-income group, which was above the minimum share set during the scheme.

Why GBIS focused on individual measures

GBIS was designed mainly around one insulation measure per home. That made it different from ECO4, which uses a broader whole-house approach for eligible fuel-poor and vulnerable households. The simpler GBIS model was intended to make common measures easier to deliver at scale.

A one-measure model can be useful where the main weakness is clear, such as a poorly insulated loft or a suitable empty cavity wall. It can be less suitable where several parts of the building need attention together. Later rule changes allowed some two-primary-measure combinations because delivery experience showed that the original design was too restrictive in some cases.

What the figures say about delivery

By the end of March 2026, provisional statistics recorded 51,400 cavity wall insulation measures, 39,500 loft insulation measures and 34,900 heating-control measures. Those three categories accounted for most delivery. Around 3,300 households received two primary measures after the rules changed.

The statistics also show that delivery was not evenly spread. The North West and West Midlands recorded the largest regional shares of measures, while the number of upgraded homes per 100,000 households was lower in Scotland than in England or Wales. Differences can reflect housing type, supplier activity, delivery capacity and local referral routes.

The budget was not a household grant pot

GBIS was commonly described as a £1 billion scheme. That figure described the policy scale and expected obligation, not a fixed cash fund that each eligible household could claim from. Suppliers funded measures to meet scheme targets, and Ofgem monitored their compliance.

The June 2026 statistical release recorded about £400.4 million in delivery costs and £24.4 million in administrative costs to the end of March 2026. Those figures were reported by suppliers and remain provisional. They should not be used to estimate what an individual installation should have cost.

Why the rules changed before closure

Government reviewed GBIS and ECO4 after delivery proved slower and more difficult than expected. The review highlighted inflation, supply-chain pressure, competition between schemes, fixed delivery costs and household contributions as practical barriers.

Changes widened some two-measure combinations, expanded the use of smart thermostats as secondary measures in qualifying cases, and allowed certain ECO4 savings to be reassigned towards GBIS targets. These were changes to supplier compliance and delivery. They did not turn GBIS into a guaranteed grant for households.

GBIS then ended on 31 March 2026 as planned. Government chose not to extend it. The later ECO4 extension was intended to support completion of existing obligations and remediation, not to continue GBIS under another name.

Who is eligible for support

GBIS is closed, so nobody can now qualify for a new GBIS installation. The historic rules remain relevant if you are checking an old application, a supplier decision, or the evidence attached to completed work.

While the scheme operated, eligibility had several layers. The home had to be in Great Britain and need an eligible improvement. The household also needed to fit the general group, the low-income group, or a Flexible Eligibility route. Even then, a supplier and assessor had to decide whether the property and proposed measure could proceed.

The general eligibility group

The general group was intended to reach less efficient homes beyond the main benefits system. In broad terms, it covered properties with an Energy Performance Certificate rating of D to G and lower council tax bands: A to D in England, and A to E in Scotland and Wales.

Those headline conditions were not a final approval. Tenure, the condition and construction of the home, the measure needed, supplier funding and technical suitability still mattered. Different rules could apply to owner-occupied, private-rented and social-rented homes.

The low-income eligibility group

The low-income group used qualifying benefits and related routes. The published benefit list included:

• Child Benefit, subject to household income thresholds;

• Pension Guarantee Credit;

• income-related Employment and Support Allowance;

• income-based Jobseeker's Allowance;

• Income Support;

• Universal Credit;

• Housing Benefit; and

• Pension Credit Savings Credit.

Receiving one of these benefits did not remove the property requirements. The home still needed to meet the relevant energy-performance and technical rules, and the supplier retained control over its offer.

How the Child Benefit route worked

Child Benefit was not an automatic passport. The household also had to be below a gross annual income threshold based on whether there was one claimant or a couple and on the number of children or qualifying young people.

For this purpose, the guidance treated a child as someone under 16. A qualifying young person could include someone under 20 in approved education or training. Evidence of benefit receipt, family composition and income could be required.

How GBIS Flex widened the route

GBIS Flex allowed participating local authorities and the Scottish and Welsh governments to refer some households that did not receive a listed means-tested benefit. The route was designed for homes needing energy-efficiency work where the household was low income or vulnerable to the effects of a cold home.

The main published routes included combined gross household income below £31,000, or a severe or long-term health condition made worse by cold living conditions. Examples included cardiovascular or respiratory conditions, limited mobility and immunosuppression. Local statements of intent could contain further criteria and evidence requirements.

Suppliers also had a Flex route for some households receiving persistent fuel-debt support or repeatedly unable to stay connected on a prepayment meter because of financial hardship. A referral was evidence for the route, not a promise that an installation would be funded.

Tenure, consent and supplier discretion

Homeowners and tenants could receive support, but tenants needed the owner's or landlord's permission. That included homes owned by social housing providers or managed by another organisation. In the private rented sector, property standards, landlord obligations and scheme rules could also affect what was appropriate.

A household did not have to be a customer of the supplier funding the work. While GBIS operated, people could approach any obligated supplier. However, suppliers were not required to support every eligible household, and eligibility never guaranteed installation.

Types of insulation covered

GBIS was an insulation scheme, not a general home-improvement fund. Its main purpose was to support named energy-efficiency measures that reduced heat loss. Limited heating controls could be added in some low-income cases, but windows, routine repairs, solar panels and general boiler replacement were not part of the standard GBIS measure list.

The main insulation measures

The published measure list covered:

• cavity wall insulation, including party cavity walls;

• loft insulation;

• solid wall insulation;

• pitched roof insulation;

• flat roof insulation;

• under-floor insulation;

• solid floor insulation;

• park home insulation; and

• room-in-roof insulation.

Each name describes a broad category rather than a one-size-fits-all product. The construction, condition and exposure of the home determined whether a measure was technically appropriate.

Which measures were installed most often?

The latest provisional statistics show that cavity wall insulation was the most common measure, with 51,400 installations, or 37% of all measures. Loft insulation accounted for 39,500 measures, or 28%. Heating controls accounted for 34,900 measures, or 25%.

These figures show what suppliers delivered at scale. They do not mean these measures are automatically best for a particular home. A common measure can still be unsuitable where there is damp, a construction defect, severe weather exposure, inaccessible areas or inadequate ventilation.

How two-measure cases worked

GBIS was originally designed mainly around one primary insulation measure per household. Mid-scheme changes later allowed some combinations of two primary measures, including combinations drawn from cavity wall, loft, under-floor, solid floor and pitched roof insulation.

Provisional data show around 3,300 households received two primary measures between January 2025 and the end of March 2026. That was still a minority. Most of the 100,900 upgraded households received only one measure, while some received one primary measure plus linked heating controls.

When heating controls were included

Certain heating controls could be installed as secondary measures in qualifying owner-occupied homes in the low-income group. Examples included room thermostats and boiler programmers. They were linked to an eligible insulation measure and were not generally a route to standalone control upgrades.

The purpose was to help the heating system respond more effectively after heat loss had been reduced. Controls can change how a home uses energy, but they do not guarantee a bill saving. Results depend on the heating system, settings, household behaviour and energy prices.

Why the condition of the home mattered

A measure being on the scheme list was only the starting point. A retrofit assessment should have considered the building type, existing insulation, defects, moisture, ventilation, access, heating pattern and how different parts of the home worked together.

This whole-building view is particularly important for solid wall, floor and room-in-roof work. Insulation can alter temperatures and moisture movement. Poor detailing around windows, roofs, floors, vents and services can create cold bridges, trapped moisture or mould rather than solving the original problem.

Pre-existing leaks, penetrating damp, defective gutters, damaged pointing or inadequate ventilation may need attention before insulation. Scheme funding did not automatically cover every repair needed to make a property ready for work.

How funding works

GBIS funding was often described as a grant, but the delivery model was different. The scheme placed an obligation on energy suppliers. Suppliers funded eligible work to meet legally defined targets, usually through contracted installers and delivery partners.

There was no standard household award and no central voucher. Ofgem administered supplier compliance, but it did not set one contribution amount for every home or choose the installer for an individual household.

Why offers varied between homes

A supplier considered the type and cost of the measure, the modelled energy saving, property risk, delivery capacity and its remaining obligation. This could make a straightforward loft or cavity-wall job easier to support than a complex solid-wall installation.

Two households with similar incomes could therefore receive different offers. One might receive fully funded loft insulation. Another might be asked to contribute towards solid wall work. A third might receive no offer because the property was unsuitable or the supplier chose not to fund the project.

That variation was built into the supplier-obligation model. It did not make every request for payment improper. It also meant advertising that promised free insulation to everyone was misleading.

What a household contribution meant

A consumer financial contribution was the amount a household agreed to pay towards the installation. Ofgem highlighted higher-cost measures, including solid wall insulation, as more likely to involve a contribution. There was no universal price list.

Before agreeing, the household should have received a written quote or proposal showing the work, the contribution, what was included, what was excluded and who was responsible for the remaining cost. From summer 2024, contribution information also had to be recorded in the TrustMark Retrofit Portal, with evidence available if requested.

A contribution did not buy a guaranteed level of saving. Any estimate depended on assumptions about the building, measure, heating use and energy prices. The contract, guarantee and design documents were more useful for checking what had actually been promised.

What the scheme cost overall

The June 2026 release recorded provisional delivery costs of about £400.4 million and administrative costs of about £24.4 million to the end of the scheme. These were supplier-reported programme costs, excluding VAT in the delivery-cost definition.

The figures cannot be divided by the number of homes to produce a fair price for one installation. Measures varied widely, and programme costs included activities such as finding properties, marketing, compliance, monitoring and administration.

Why public funding could not be double counted

Ofgem guidance prevented GBIS measures from being blended with other government funding for the same work. The principle was to avoid two schemes paying for the same measure or changing the property assessment in a way that made the scheme evidence unreliable.

This did not stop a home receiving separate work through another route at a different time, provided the rules of both schemes were met. It did mean that the sequence, scope and funding source needed to be clear before work started.

What happens to funding after closure?

There is no remaining GBIS pot for new households to claim. An uncompleted enquiry or historic indication of eligibility does not reserve money after 31 March 2026. A supplier may discuss another scheme or a private quotation, but it should not describe new work as a GBIS installation.

Closure does not remove rights connected with completed work. Guarantees, complaint routes, record checks and the official wall-insulation remediation programme can still apply. Remediation offered through an official quality process should not be confused with a new grant application.

How to check if you qualify

You cannot now qualify for GBIS because the scheme has ended. This section explains how to check whether a past application or installation appears to have followed the GBIS route, and how to separate that question from eligibility for current support.

First decide what you are trying to check

Most enquiries now fall into one of three groups:

• an application or offer made before 31 March 2026;

• insulation that was completed and said to be funded by GBIS; or

• new help with insulation or heating after GBIS closed.

The right evidence and contact route depends on which group applies. A historic EPC or benefit letter may explain an old eligibility decision. It does not establish eligibility for a scheme that is open now.

Checking an old application or offer

Start with the name of the supplier or installer, the date of the enquiry, the proposed measure and any written confirmation of the scheme. Ask whether the installation was completed by 31 March 2026 and whether it was lodged as a GBIS measure.

A useful written request asks for:

• the scheme and eligibility route recorded for the property;

• the name of the obligated supplier and installer;

• the assessment outcome and proposed measure;

• the agreed household contribution, if any;

• the installation and completion dates;

• the TrustMark lodgement or certification details;

• the Unique Measure Reference, where available; and

• the guarantee, warranty and handover documents.

A supplier may still be validating records or resolving a complaint. That is different from keeping an application open for a new GBIS installation. If the work was not completed by the scheme deadline, ask whether any alternative offer is being made and under which current scheme or private contract.

Checking completed work

Look for a clear chain from assessment to handover. The documents should identify the property, measure, installer, supplier or funder, any contribution, the date, and the guarantee or warranty. Photographs, invoices, emails and certificates can help if the description in the paperwork is unclear.

If you do not know the installer, Ofgem says you can request relevant information by emailing [email protected]. It currently asks for two recent documents showing that you live at the property. A subject access request can help identify records, but it is not a technical assessment of the work.

If you cannot find a guarantee for a measure installed after 1 January 2020, Ofgem directs consumers to TrustMark. TrustMark can also help identify the scheme provider linked to a registered business.

Checking current support

Current support must be checked from the beginning. The open route depends on the nation, tenure, EPC, income or benefits, property condition, proposed measure and local funding. Rules that resemble GBIS may still use different thresholds or delivery processes.

In England, the Warm Homes: Local Grant is one current route for eligible privately owned homes with EPC D to G, subject to local authority funding. ECO4 remains in force to 31 December 2026, but it is supplier-led and the extension did not increase supplier targets. Scotland and Wales have their own national programmes, discussed later in this guide.

Do not rely on an online label alone

A legitimate website can still contain an old page, and a trader can use a familiar scheme name inaccurately. Check the publication date, scheme end date and official administrator. For current work, ask the provider to state the exact scheme, funder, eligibility route and complaints framework in writing.

How to apply

You cannot make a new GBIS application. The scheme ended on 31 March 2026, and forms that were shared with ECO4 now apply only to ECO4 projects.

What you do next depends on whether you had an existing GBIS enquiry, completed work, or a new need for support.

If you applied before the deadline

Contact the supplier or installer named in your correspondence. Do this through an independently verified email address or telephone number rather than replying to an unexpected message. Ask for the status and scheme record in writing.

A clear request can cover:

• whether any GBIS measure was completed by 31 March 2026;

• whether the measure was lodged and accepted for scheme purposes;

• whether an offer expired without installation;

• whether any payment or deposit is held;

• which documents and guarantees should have been issued; and

• whether a different current scheme or private offer is proposed.

Do not assume that an assessment, referral or signed expression of interest guaranteed funding. Under the scheme, suppliers chose which projects to support. If the installation was not completed by the deadline, a new proposal needs its own lawful and transparent funding basis.

If work was completed

You do not need to apply again to preserve a guarantee or raise a concern. Keep the assessment, contract, contribution record, installer details, photographs, certificates, Unique Measure Reference and guarantee together. If something is missing, ask the installer and supplier for a copy.

For workmanship or technical concerns, start with the installer where possible and follow the TrustMark complaints process. For external wall insulation, use the dedicated government and Ofgem route described in the consumer-protection section.

If someone offers a new GBIS installation

Pause and verify the claim. A company may legitimately contact you about inspection, records, complaints or remediation connected with old GBIS work. It should not present a new post-deadline installation as a live GBIS award.

Ask the caller to give the organisation name, purpose, scheme, property reference and official contact details. End the call, find the organisation's number independently, and check the information before sharing documents or allowing access to your home.

How to look for current support

Use the official service for your nation or scheme. Complete only the information needed for an initial check. A current programme may arrange a survey before deciding what, if anything, it can fund.

A sensible current journey is:

• check the official scheme territory and status;

• review the broad household and property criteria;

• use the official application or referral route;

• allow a property survey where the enquiry proceeds;

• review the proposed work, funding and documents; and

• decide whether to continue without sales pressure.

Home assessment and installation

For completed GBIS work, the assessment and installation records are central to understanding what should have happened. A scheme eligibility check considered the household route. A retrofit assessment considered the building. Those were related steps, but they answered different questions.

The assessment should not have been a quick promise that a popular product would fit every home. Its purpose was to identify the construction, condition, risks and improvement options before design and installation.

What the assessment should have considered

A competent assessment should have gathered enough information to understand the home as a system. Relevant checks could include:

• the age, construction and exposed location of the building;

• the EPC or other energy-assessment information;

• existing insulation and previous alterations;

• roof, wall, floor and window condition;

• leaks, damp, mould and condensation patterns;

• ventilation, extract fans and combustion appliances;

• electrical services, pipes and other hidden hazards;

• access for installation and future maintenance; and

• how rooms were heated and used.

Questions about condensation, unused rooms or old leaks can feel unrelated to insulation. They are important because insulation changes surface temperatures and air movement. A design that ignores existing moisture or ventilation problems can make them harder to manage.

The main retrofit roles

GBIS delivery generally sat within the TrustMark and PAS retrofit framework. The assessor gathered property information. A Retrofit Coordinator oversaw risk and process. A Retrofit Designer specified the solution where design was needed. A registered installer carried out or took responsibility for the work.

The same person or business could perform more than one role where the rules allowed, but the responsibilities should still be identifiable. Registration or certification shows that a business sits within a scheme framework. It does not guarantee that every job will be fault-free.

What should have happened before work began

Before installation, the household should have received a clear proposal. It should identify the measure, location, specification, installer, contribution, preparatory work, likely disruption, guarantee and complaints route. Any defects that had to be repaired first should also have been explained.

Building Regulations and building-control arrangements differ across England, Wales and Scotland. The installer or project team should have explained which requirements applied and who would provide evidence of compliance. Planning, listed-building or conservation-area permission could also matter for visible external work.

Older buildings can contain asbestos in boards, coatings, soffits, pipe insulation and other materials. The Health and Safety Executive advises that buildings constructed or refurbished before 2000 may contain asbestos. Intrusive work may require an appropriate survey and safe management by competent people.

What installation and handover should include

The work should match the agreed design and manufacturer instructions. Details around edges, openings, eaves, floors, vents, cables and pipes are often as important as the main area of insulation. Poor junctions can leave cold bridges or routes for moisture.

At handover, useful documents include:

• the final scope and specification;

• the installer and scheme-provider details;

• the completion and lodgement record;

• the Unique Measure Reference, where issued;

• Building Regulations or other compliance evidence;

• the guarantee and warranty documents;

• ventilation or control instructions;

• maintenance information; and

• the complaints contact and escalation route.

Keep the documents for the life of the measure and pass them to a future owner where appropriate. They can be important for complaints, remediation, later building work and questions during a sale.

What to check after installation

Look for signs that the work differs from the proposal, blocks ventilation, causes water entry, leaves exposed materials or creates new cold and damp areas. A change in condensation does not by itself prove that insulation is defective, but it is a reason to record what is happening and seek a qualified assessment.

Do not cut into walls, lift fixed insulation or block vents to investigate. Take photographs, note dates and weather conditions, and keep energy or humidity records if they are readily available. Then raise the issue through the installer and official quality route.

External wall insulation installed under GBIS is covered by a dedicated government checking programme. All properties with qualifying external wall insulation are to be offered a home check. If work is found to be faulty, the installer is expected to fix it and the household should not be asked to pay for that remediation.

How GBIS compares to others

GBIS is now a closed scheme, so the useful comparison is between its former role and support that may be available today. No single programme is a direct replacement across Great Britain.

The right starting point depends on where you live, who owns the home, its EPC rating, household circumstances, the work needed and whether local funding remains available.

GBIS and ECO4

Both schemes placed obligations on energy suppliers, but they were designed differently. GBIS mainly supported one insulation measure and later allowed some two-measure combinations. ECO4 uses a whole-house approach and is targeted more tightly at fuel-poor and vulnerable households.

ECO4 has been extended to 31 December 2026. Government said the extension was to give suppliers more time to meet existing targets and remediate non-compliant work. It did not increase the target or create a guaranteed place for a new household. Availability remains supplier-led and subject to the current rules and assessment.

Warm Homes: Local Grant in England

The Warm Homes: Local Grant is an England-only programme delivered through local authorities. GOV.UK says it can support privately owned homes, including privately rented homes, with an EPC of D to G. Household income is usually £36,000 a year or less, although benefit and postcode routes can also apply.

If the application proceeds, the local authority arranges a survey and agrees the work. Owner-occupiers do not normally contribute to agreed improvements. A landlord may need to contribute, depending on the property and programme rules. Funding is limited, so meeting broad criteria does not guarantee work.

Support in Scotland

Warmer Homes Scotland provides energy-efficiency and heating improvements for qualifying homeowners and private tenants. Eligibility includes household and property conditions, and Home Energy Scotland is the official starting point for advice and referral.

Scotland also has other advice, grant and loan routes that change over time. Check the current Home Energy Scotland service rather than assuming that GBIS council-tax or benefit rules carry across.

Support in Wales

Nest is a Welsh Government programme offering free impartial advice and, for qualifying households, a tailored package that can include insulation, heating, heat pumps or solar panels. The detailed criteria use tenure, household income or means-tested benefits, EPC and, in some cases, health conditions.

Green Homes Wales is a separate route for eligible homeowners considering interest-free finance and expert support for energy-efficiency or low-carbon improvements. A loan is not the same as grant funding, so repayment terms and affordability need separate consideration.

The Boiler Upgrade Scheme

The Boiler Upgrade Scheme is for low-carbon heating rather than general insulation. It operates in England and Wales and is normally applied for by the MCS-certified installer on the property owner's behalf.

As at September 2026, the standard grants are £7,500 for an air-to-water air source heat pump, £7,500 for a ground or water source heat pump, £5,000 for a qualifying biomass boiler and £2,500 for an air-to-air heat pump. Until March 2027, an extra £1,500 may be available for qualifying oil- or LPG-heated properties without a mains gas connection. Current eligibility and technical conditions must be checked before relying on these amounts.

A heating grant does not establish that a heat pump suits the home or will reduce bills. System design, heat loss, emitters, hot water, electricity tariffs and installation quality all matter.

How to compare routes sensibly

Start with the problem rather than the scheme name. A cold loft with little insulation is different from a solid-wall home needing coordinated repairs and ventilation. Replacing a fossil-fuel heating system is different again.

Compare:

• the nation and type of property covered;

• whether the scheme is open and funded locally;

• household and EPC criteria;

• the survey and design process;

• which measures can be included;

• any landlord or household contribution;

• quality, guarantee and complaint arrangements; and

• what happens if the property needs repairs first.

Do not agree to a measure simply because funding is available. The work still needs to be suitable for the building and clear in writing.

Your rights and consumer protections

GBIS closing did not remove the paperwork, guarantees or complaint routes connected with completed work. The correct route depends on whether the issue is technical workmanship, a contract or payment dispute, a supplier complaint, a missing record, or part of the official wall-insulation remediation programme.

Keep the issue specific. A regulator, quality scheme, ombudsman and court have different roles. Sending the same complaint everywhere at once can slow matters down and may cause you to miss the process that applies.

Start by gathering the core records

Before raising a complaint, collect what you can without altering the installation:

• what was installed and where;

• the installation and completion dates;

• the supplier, installer and scheme-provider names;

• the contract, quotation and contribution record;

• the assessment and design documents;

• the guarantee, warranty and handover pack;

• the Unique Measure Reference or lodgement details;

• photographs and a dated description of the problem; and

• copies of emails, letters and call notes.

Describe what you can observe rather than deciding the technical cause yourself. For example, record where damp appeared, when it started and what changed. A qualified inspection may be needed to distinguish a defective installation from a leak, ventilation problem or unrelated building defect.

The TrustMark complaints route

TrustMark describes a three-stage process. First, raise the complaint with the registered business that carried out the work. Explain the concern, what outcome you are seeking, and allow a reasonable opportunity to respond. Keep the communication in writing where possible.

If the issue is not resolved, escalate it to the business's Scheme Provider. The provider is the organisation through which the business obtained its TrustMark registration for the relevant trade. You can usually identify it through the TrustMark business search or paperwork.

A dispute may then be eligible for the Dispute Resolution Ombudsman after the earlier stages and current timing conditions have been met. The service does not cover every type of complaint, particularly some commercial, compensation or legal disputes. Check the current criteria before relying on it.

What Ofgem can and cannot do

Ofgem administered GBIS and monitors supplier compliance. It does not normally resolve the private contract between a householder and an installer. Its complaints guidance can help identify the information and bodies needed to pursue a dispute.

If you do not know the installer, Ofgem accepts subject access requests at [email protected] and asks for two recent documents proving residence at the property. If you have a wall-insulation concern, use the separate wall-insulation contact route and include the Unique Measure Reference if you have it.

Consumer law may also matter

General consumer law sits alongside scheme rules. A trader providing a service must usually carry it out with reasonable care and skill. What remedy is available depends on the contract, the problem, what has already been offered and the law applying to the circumstances.

A 14-day cancellation period often applies to consumer contracts made at a distance or away from business premises, such as in the home. There are exceptions, especially where work starts during that period at the consumer's request. Do not assume the same cancellation right applies to every agreement.

Citizens Advice can explain consumer rights in England and Wales and refer suitable information to Trading Standards. Advice Direct Scotland provides consumer advice in Scotland. Consider independent legal advice where the dispute involves significant loss, liability, limitation periods or court action.

The dedicated wall-insulation route

Government identified quality issues in some internal and external wall insulation fitted through GBIS and ECO4. Ofgem has written to affected properties. All properties with qualifying external wall insulation are to be offered a quality check by qualified professionals.

If external wall insulation is found to be faulty, the official guidance says the installer will be asked to fix it and the household should not be asked to pay. Contacts involved in this process should use the property's Unique Measure Reference. You can verify a contact through the Ofgem wall-insulation webform or helpline on 0808 169 4447.

For internal wall insulation, government says its audit found fewer issues and no action should generally be required, but households with concerns can still contact Ofgem. Separate installation complaints can follow the TrustMark route.

When the Energy Ombudsman may be relevant

The Energy Ombudsman deals with complaints about covered energy suppliers, network operators and certain energy services after the organisation's complaint process has been used. It is not a universal ombudsman for every insulation installer or building dispute.

Use it only where the complaint falls within its current scope, such as the way an energy supplier handled a covered matter. For workmanship, the installer, TrustMark, scheme provider, guarantee provider or another relevant dispute service may be the correct route.

Safety and urgent problems

Do not wait for a formal complaint to finish if there is an immediate safety concern. Keep away from exposed electrical parts, unstable materials or suspected asbestos. For dangerous building conditions, gas or electrical risks, fire or serious water entry, contact the appropriate emergency service or qualified professional.

Damp and mould can affect health, but the cause should be assessed rather than assumed. Contact the landlord or housing provider promptly in rented accommodation and use local environmental health or housing routes where conditions remain unsafe.

How to avoid scams

The clearest current fact is that GBIS is closed. A person who offers a brand-new GBIS grant or asks you to apply for a new GBIS installation is using an out-of-date or misleading description.

That does not mean every contact mentioning GBIS is fraudulent. Suppliers, Ofgem, TrustMark, certification bodies and installers may still contact households about records, audits, complaints, guarantees or remediation. The purpose and reference should be verifiable.

Warning signs after scheme closure

Pause where a caller, visitor, advert or message:

• claims GBIS has reopened without an official source;

• guarantees free work before checking the property;

• pressures you to sign or pay on the same day;

• says you must switch energy supplier;

• will not name the supplier, installer or scheme;

• asks for bank details before explaining the contract;

• uses a copied logo or a web address that is almost correct;

• refuses to provide TrustMark or business details;

• asks you to keep the offer secret; or

• says a fee is needed to release government funding.

Remediation should not be sold as a new funding opportunity. For the official external wall-insulation process, the guidance says the household should not be asked to pay for faulty work to be put right.

Verify the contact independently

Do not use the telephone number or link supplied by the person until you have checked it. Find the organisation through GOV.UK, Ofgem, TrustMark or another official register. End the conversation and make a fresh call.

Ask for the full business name, registered address, company number, TrustMark registration, scheme provider, supplier, reason for contact and property reference. A genuine organisation should allow time for verification and should explain how it obtained your details.

Ofgem warns that fraudsters may impersonate it through calls, messages, social media or doorstep visits. Ofgem does not sell energy. Treat unexpected requests for personal or financial information as suspicious and verify them through an official Ofgem route.

Protect documents and personal information

Eligibility and retrofit files can contain benefit, income, health and property information. Share only what is needed, with an organisation whose identity and purpose you have checked. Do not send complete bank statements, identity documents or medical details simply because a cold caller says they are required.

Check privacy information before submitting an online form. It should say who controls the data, why it is collected, who may receive it and how to exercise your rights. A form should not be presented as making a final scheme or technical decision.

What to do after a suspicious contact

Do not click links, install software or allow remote access. Save the message, telephone number, web address and any payment details. If you gave banking information or lost money, contact your bank immediately.

In England, Wales and Northern Ireland, fraud and cyber crime can be reported to Report Fraud online or by calling 0300 123 2040. In Scotland, report fraud to Police Scotland on 101. Call 999 where a crime is in progress or someone is in immediate danger.

Forward suspicious emails to [email protected] and suspicious texts to 7726. If you reused a password or entered it on a suspicious site, change it on the affected account and anywhere else it was used.

A report does not guarantee that money will be recovered or that an investigation will follow. It can help the relevant bodies identify patterns and protect other consumers.

Conclusion

The Great British Insulation Scheme ended on 31 March 2026. It delivered 139,100 provisional measures in 100,900 households across England, Scotland and Wales, mainly through cavity wall insulation, loft insulation and heating controls.

Its main lesson is that a scheme label never answered every household question. Eligibility, property condition, supplier funding, design, contribution and quality assurance all mattered. The same principle applies to current support.

For completed GBIS work, keep the assessment, proposal, contribution record, TrustMark details, Unique Measure Reference, completion evidence and guarantee. Those documents connect the property to the right installer, supplier and complaint route.

For new improvements, begin with the official route for your nation and the problem you need to solve. Funding should support a suitable design, not replace the need for one.

What happens next

Choose the path that matches your position:

• Old application: ask the supplier what was completed, lodged or closed.

• Completed work: organise the records and check the guarantee.

• Workmanship concern: contact the installer, then follow the quality route.

• Wall-insulation concern: use the dedicated Ofgem checking service.

• New insulation need: check a current national or local scheme.

• New private quote: arrange a property assessment and compare documents.

• Suspicious contact: stop, verify independently and report it if needed.

Take time to understand who is offering the work, what it is meant to achieve, how it will be funded and what protection applies afterwards. A clear written process is more useful than a confident promise.

Clearwise publishes general information and can introduce consumers to independent providers with consent. It does not decide scheme eligibility, survey a property, design retrofit work or guarantee that a provider will be able to assist.

Frequently asked questions

Scheme

Eligibility

Measures

Costs

Applying

Protection

Scams

Alternatives

Useful organisations

Ofgem

Ofgem administered GBIS and continues to publish scheme data, complaints guidance and the dedicated wall-insulation checking route. It does not normally resolve the private contract with an installer. For affected wall insulation, use the official webform or call 0808 169 4447 and give the Unique Measure Reference if you have it.

• 0808 169 4447
• www.gov.uk

TrustMark

TrustMark is the government-endorsed quality scheme used for GBIS retrofit work. Its website can help you check a registered business, identify the Scheme Provider and follow the three-stage complaints process. TrustMark also provides information about the external wall-insulation remediation programme.

• 0333 555 1234
• www.trustmark.org.uk

Citizens Advice

Citizens Advice provides consumer guidance in England and Wales. The consumer service can explain rights linked to home-improvement contracts, cancellation, poor workmanship and misleading sales, and can pass suitable information to Trading Standards. In Scotland, use Advice Direct Scotland for consumer advice.

• 0808 223 1133
• www.citizensadvice.org.uk

Energy Ombudsman

The Energy Ombudsman is a free independent service for complaints within its energy-sector scope after the relevant company has had an opportunity to respond. It may be relevant to the handling of a covered supplier matter, but it is not a general ombudsman for every insulation installer or building dispute.

• 0330 440 1624
• www.energyombudsman.org

References

Still have questions?

Even a detailed guide cannot answer every real-world GBIS question, because the scheme is not decided by headline rules alone. Two households can look similar on paper and still end up with different answers once the property construction, moisture risk, tenure, delivery route, contribution level or local Flex criteria are examined properly. That is exactly why speaking with an expert can be so helpful. A guide can explain the framework; an expert can help you understand how that framework applies to your home, your circumstances and your options.