GBIS Grant: Great British Insulation Scheme Explained

What is the Great British Insulation Scheme?

The Great British Insulation Scheme (GBIS) is a UK government programme that funds insulation upgrades for homes in England. GBIS launched in July 2023 and is scheduled to run until March 2026, with a target of upgrading 300,000 homes (DECC GBIS guidance for delivery partners, v5.0, February 2026).

GBIS is delivered through energy suppliers and their installers. Suppliers are obligated to fund insulation measures under the scheme as part of their Energy Company Obligation (ECO) requirements. Unlike previous ECO schemes, GBIS focuses exclusively on insulation rather than heating systems, and eligibility is based primarily on Council Tax band rather than income-tested benefits (Ofgem ECO4 and GBIS guidance, v11, March 2026).

GBIS is not a grant you apply for directly. Instead, you contact an installer registered with GBIS, who assesses your property and arranges funding through their energy supplier partner. Most eligible households pay nothing for the installation, though some households in higher Council Tax bands may be asked for a contribution (typically 10-20% of the cost).

Who qualifies for GBIS?

GBIS eligibility depends on your property's Council Tax band and, in some cases, whether you receive certain benefits. The scheme has two routes:

General route (Council Tax bands A-D)

All owner-occupiers and private tenants in Council Tax bands A-D in England are eligible for GBIS, regardless of income or benefit status (GOV.UK guidance: Improve your home's energy efficiency with help from government, updated April 2026).

In Bristol, around 65% of properties are in Council Tax bands A-D, including most Victorian and Edwardian terraces in areas like Southville, Totterdown, St Pauls, Easton, St George, and Fishponds. Newer estates and flats in Bedminster, Brislington, and Hartcliffe also typically fall within these bands.

Benefits route (Council Tax bands E-H)

If your property is in Council Tax band E, F, G, or H, you can still qualify for GBIS if anyone in your household receives one of these means-tested benefits:

• Universal Credit
• Pension Credit (Guarantee Credit or Savings Credit)
• Income Support
• Income-based Jobseeker's Allowance (JSA)
• Income-related Employment and Support Allowance (ESA)
• Child Tax Credit
• Working Tax Credit

In Bristol, bands E-H include larger Victorian and Edwardian houses in areas like Clifton, Redland, Cotham, and Bishopston, as well as detached houses in Westbury-on-Trym, Henleaze, and Stoke Bishop.

Who is not eligible?

GBIS does not cover:

• Social housing tenants (housing association or council tenants). Social landlords have separate funding streams for insulation upgrades.
• Properties in Scotland, Wales, or Northern Ireland. GBIS applies only to England. Scotland has the Home Energy Scotland Grant and Loan scheme, Wales has Nest, and Northern Ireland has separate schemes.
• Properties in Council Tax bands E-H where the household does not receive an eligible benefit.
• New-build properties completed after 2012 (these are required to meet modern building regulations for insulation).
• Properties that have already received GBIS or ECO4 funding for the same insulation measure.

What insulation measures does GBIS cover?

GBIS funds a range of insulation measures. The installer will assess your property and recommend the most cost-effective measures based on your current insulation levels:

Loft insulation

Topping up loft insulation to 270mm (the current building regulation standard). Most Bristol homes built before 2000 have 100mm or less, and many Victorian terraces have no loft insulation at all. Loft insulation typically costs £300-£600 for a typical terraced house, but is fully funded under GBIS for eligible properties.

Cavity wall insulation

Filling the cavity between inner and outer walls with insulation material (typically mineral wool, polystyrene beads, or foam). Most Bristol properties built between 1920 and 1990 have cavity walls, but many remain uninsulated. Cavity wall insulation costs around £600-£1,200 for a typical semi-detached house and can save £200-£300 per year on heating bills (Energy Saving Trust: Cavity wall insulation, updated March 2026).

Solid wall insulation

Adding insulation to the inside or outside of solid walls (walls with no cavity). Most Bristol properties built before 1920 have solid walls, including the city's extensive Victorian and Edwardian terrace stock. Solid wall insulation is expensive (£8,000-£15,000 for a typical house), but GBIS covers most or all of the cost for eligible households. Savings are around £300-£500 per year on heating.

Underfloor insulation

Insulating suspended timber floors, common in Victorian and Edwardian properties. Underfloor insulation can be installed from below (if there is access to the void) or from above (lifting floorboards). Costs vary widely depending on access, but GBIS funding typically covers £1,500-£4,000 of work. Savings are around £100-£200 per year.

Room-in-roof insulation

Insulating loft conversions or rooms built into the roof space. If your property has a habitable room in the loft (common in Bristol terraces with third-floor bedrooms or offices), GBIS can fund insulation of the sloping ceilings and walls.

What GBIS does not cover

GBIS does not fund:

• Heating systems (boilers, heat pumps, radiators). These are covered by ECO4 instead.
• Windows or doors (though draught-proofing may be included as part of an insulation package).
• Solar panels or battery storage.
• Ventilation upgrades (though some ventilation work may be required after insulation to prevent condensation and mould).

How does GBIS compare to ECO4?

GBIS and ECO4 are both government schemes delivered through energy suppliers, but they have different eligibility criteria and cover different measures. Understanding the differences helps you work out which scheme is right for your Bristol home.

Which scheme should you apply for?

If you qualify for both GBIS and ECO4 (for example, you are in Council Tax band D and receive Pension Credit), the installer will recommend which scheme is better for your property:

• Choose GBIS if you only need insulation and no heating upgrades. GBIS is faster to process and has simpler eligibility checks.
• Choose ECO4 if you need both insulation and a new heating system (for example, replacing an old boiler with a heat pump, or upgrading from storage heaters). ECO4 covers a broader range of measures in a single installation.

Many installers work with both schemes and will assess which route gives you the most comprehensive upgrade for your home. You cannot combine funding (for example, getting loft insulation through GBIS and a heat pump through ECO4 in the same installation), so the installer will plan the work under one scheme or the other.

How do you apply for GBIS in Bristol?

GBIS is not a grant you apply for through a government portal. Instead, you contact an installer who is registered to deliver GBIS, and they arrange the funding and installation. Here is the process:

Step 1: Check your Council Tax band

You can find your property's Council Tax band on your council tax bill, or search the VOA Council Tax band checker. If your property is in band A-D, you automatically qualify for GBIS (subject to the property meeting technical requirements). If you are in band E-H, check whether you receive an eligible benefit.

Step 2: Contact a GBIS-registered installer

Find an installer registered to deliver GBIS. Most large insulation companies and ECO installers work with GBIS. You can search for installers by postcode on comparison sites like Simple Energy Advice (run by Energy Saving Trust) or contact major suppliers' ECO teams directly (British Gas, E.ON, Octopus Energy, EDF, and others all participate in GBIS).

Be cautious of cold-calling installers. Some legitimate GBIS installers do outreach calls, but scams are common. Always verify the company is registered with TrustMark or a member of a trade body like the National Insulation Association before agreeing to a survey.

Step 3: Property survey

The installer will visit your property to assess what insulation is already in place and what measures are suitable. They will check:

• Current loft insulation depth (if you have a loft)
• Whether your walls are cavity or solid, and whether they are already insulated
• Underfloor construction (suspended timber or solid concrete)
• Any structural issues that might affect insulation (for example, damp, asbestos, or poor roof condition)

The survey is usually free. The installer will then submit your details to their energy supplier partner to confirm eligibility and secure funding.

Step 4: Funding approval

The energy supplier checks your eligibility (Council Tax band, benefits status if applicable, property ownership) and approves funding. This typically takes 1-3 weeks. If approved, you will be told what measures are covered and whether you need to pay a contribution (most band A-D households pay nothing; some band E-H households may be asked for 10-20% of the cost).

Step 5: Installation

Once funding is approved, the installer schedules the work. Installation time depends on the measures:

• Loft insulation: 1-2 days for a typical house
• Cavity wall insulation: 1 day (external injection takes a few hours)
• Solid wall insulation: 2-4 weeks (external wall insulation requires scaffolding and rendering; internal wall insulation involves significant interior work)
• Underfloor insulation: 2-5 days depending on access

After installation, you will receive a completion certificate. For cavity wall and solid wall insulation, you should also receive a 25-year guarantee from the installer or insulation manufacturer.

Step 6: Post-installation checks

Ofgem requires a proportion of GBIS installations to be inspected by independent assessors to ensure quality. You may be selected for an inspection (this is a good thing, not a sign of a problem). The assessor will check that the insulation was installed to the correct standard and issue a compliance certificate.

What are the benefits of GBIS for Bristol households?

GBIS provides significant financial and comfort benefits for eligible Bristol households:

Lower heating bills

Proper insulation reduces heat loss, meaning you use less energy to keep your home warm. Typical savings depend on the measures installed:

• Loft insulation: £200-£250 per year (Energy Saving Trust: Loft insulation, updated February 2026)
• Cavity wall insulation: £200-£300 per year
• Solid wall insulation: £300-£500 per year
• Underfloor insulation: £100-£200 per year

For a typical Bristol terrace with solid walls, no loft insulation, and uninsulated floors, combining all three measures through GBIS could save £600-£900 per year on heating. At current energy prices (around 25p/kWh for electricity and 6p/kWh for gas as of May 2026), that is a substantial saving.

Warmer, more comfortable home

Insulation does not just save money; it makes homes more comfortable. Uninsulated Bristol terraces are notoriously cold in winter, with heat escaping through walls, floors, and lofts. After insulation, rooms warm up faster, draughts reduce, and the home feels more even in temperature.

Reduced carbon emissions

Homes account for around 20% of the UK's carbon emissions (DESNZ UK Greenhouse Gas Emissions statistics, 2024 final figures). Insulating your home cuts emissions by reducing the energy needed for heating. A typical solid wall insulation installation saves around 2-3 tonnes of CO₂ per year for a gas-heated home.

Increased property value

Insulated homes typically have higher Energy Performance Certificate (EPC) ratings, which can increase property value and appeal to buyers. A study by the Department for Energy Security and Net Zero found that moving from EPC band D to C increases property value by around 1-3% on average (DESNZ research on EPC impact on property prices, 2024).

What are the risks and downsides of GBIS?

While GBIS provides significant benefits, there are some risks and limitations to be aware of:

Insulation quality varies

Not all installers deliver the same quality. Poorly installed insulation can be ineffective or even cause problems like condensation, damp, or mould. Always use a TrustMark-registered installer and ask for references from previous customers in Bristol.

Solid wall insulation changes your home's appearance or interior space

External wall insulation adds a rendered layer to the outside of your property, changing its appearance. This can be an issue for period properties or Conservation Areas (though many Bristol Conservation Areas now permit external insulation if the design is sympathetic). Internal wall insulation takes up interior space (around 100mm per wall) and requires moving radiators, sockets, and skirting boards.

Ventilation becomes more important

Insulating your home makes it more airtight, which is good for heat retention but can increase condensation risk if ventilation is inadequate. After insulation, make sure you open windows regularly, use extractor fans in kitchens and bathrooms, and consider upgrading to trickle vents or mechanical ventilation if condensation becomes a problem.

Not all properties are suitable

Some Bristol properties cannot be insulated through GBIS:

• Cavity walls with existing cavity insulation cannot be re-insulated (though if the original insulation is faulty, it may be removed and replaced).
• Properties with significant damp, structural defects, or asbestos must resolve these issues before insulation can be installed (GBIS does not fund remedial work).
• Listed Buildings and some Conservation Area properties may not be permitted to install external wall insulation due to planning restrictions.

What happens after GBIS ends in March 2026?

GBIS is scheduled to end in March 2026, the same time ECO4 is due to finish. The UK government has not yet announced a successor scheme, though industry bodies expect a new version of ECO or a replacement programme to be launched (Energy industry press coverage, April 2026).

If you are eligible for GBIS and your property needs insulation, it is worth acting before March 2026 to secure funding under the current scheme. Waiting for a successor scheme risks delays or changes to eligibility criteria.

Frequently asked questions

What is the Great British Insulation Scheme (GBIS)?

The Great British Insulation Scheme (GBIS) is a UK government scheme that funds insulation measures for homes in Council Tax bands A-D in England, or E-H if the household receives an eligible benefit. GBIS launched in 2023 and runs until March 2026, with a target of upgrading 300,000 homes. Funding is delivered through energy suppliers and their installers.

How does GBIS differ from ECO4?

GBIS focuses solely on insulation measures (loft, cavity wall, solid wall, underfloor, room-in-roof), while ECO4 also covers heating systems like heat pumps and boilers. GBIS eligibility is based mainly on Council Tax band, whereas ECO4 requires means-tested benefits or a referral via the Flex route. GBIS covers a wider pool of households than ECO4's income-targeted approach. You cannot receive both GBIS and ECO4 funding in the same installation.

Who qualifies for GBIS in Bristol?

Bristol households in Council Tax bands A-D automatically qualify for GBIS. If your property is in band E-H, you qualify if you receive a means-tested benefit (Universal Credit, Pension Credit, Income Support, ESA, JSA, Child Tax Credit, or Working Tax Credit). You must be an owner-occupier or private tenant (social housing tenants are not eligible). Around 65% of Bristol properties are in bands A-D.

Can I get both GBIS and ECO4 funding?

No. A property can receive funding from GBIS or ECO4, but not both in the same installation. If you qualify for both schemes, your installer will recommend which is most suitable based on your property's needs. Choose GBIS if you only need insulation; choose ECO4 if you need heating upgrades alongside insulation.

How much does GBIS cost the household?

Most households in Council Tax bands A-D pay nothing for GBIS-funded insulation. Households in bands E-H on the benefits route may be asked to contribute 10-20% of the installation cost, depending on the energy supplier and installer. The contribution is agreed before work starts, so there are no surprise charges.

How long does GBIS installation take?

Installation time depends on the measures. Loft insulation takes 1-2 days. Cavity wall insulation takes around 1 day (external injection is quick). Solid wall insulation takes 2-4 weeks (external wall insulation requires scaffolding and rendering; internal wall insulation involves significant interior work). Underfloor insulation takes 2-5 days depending on access. From initial survey to completion, the process typically takes 4-8 weeks.

Will GBIS affect my home's appearance?

External wall insulation changes your home's exterior (it adds a rendered layer, typically 100-150mm thick). Internal wall insulation does not affect the exterior but takes up interior space and requires moving radiators, sockets, and skirting boards. Loft, cavity wall, and underfloor insulation are not visible once installed. If you live in a Conservation Area or Listed Building, check with Bristol City Council planning before proceeding with external wall insulation.

What if my home already has some insulation?

GBIS can still help. If your loft insulation is below 270mm, GBIS can top it up. If your cavity walls are uninsulated, they can be filled. However, GBIS cannot re-insulate walls or lofts that already meet current standards, and it does not fund removal and replacement of existing insulation unless the original installation is proven to be defective.

Can I use GBIS if I rent my home?

Yes, if you are a private tenant. You will need your landlord's written permission before the installer can proceed (insulation is classed as an alteration to the property). Social housing tenants (housing association or council tenants) are not eligible for GBIS; their landlords have separate funding streams for retrofit.

Is GBIS available in Scotland, Wales, or Northern Ireland?

No. GBIS applies only to England. Scotland has the Home Energy Scotland Grant and Loan scheme, Wales has Nest and the Warm Homes Programme, and Northern Ireland has separate schemes managed by the NI Housing Executive. If you live outside England, check your local government's energy efficiency schemes.