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Last updated: 2 July 2024

Your Guide to Cavity Wall Insulation Grants in 2024

  • Uninsulated walls are responsible for up to 33% of heat loss in a home.
  • The Great British Insulation Scheme (GBIS) and the Energy Company Obligation (ECO4) are two UK grant schemes currently offering cavity wall insulation grants.
  • Both the GBIS and ECO4 are active until March 2026.

Nearly three-quarters of all properties in the UK are built with cavity walls, yet according to the Department for Energy Security & Net Zero, up to 29% of these properties lack adequate insulation. This leads to soaring energy bills and large domestic carbon footprints as heating systems work overtime, constantly making up for the lost heat. 

That’s where cavity wall insulation comes in. A quick, non-disruptive, and highly effective upgrade that can save upwards of £405 in energy bills, and cut domestic CO2 emissions by 1.1 tonnes each year in a detached UK home. This all sounds great, but unfortunately, not every household can front the hefty costs in one go.

To help fuel-poor and energy-inefficient homes upgrade their efficiency, the UK has rolled out two key grant schemes that offer free or reduced cost of cavity wall insulation. These are the Great British Insulation Scheme (GBIS) and the Energy Company Obligation (ECO4).

This complete guide by GreenMatch UK will give you all you need to know about cavity wall insulation grants, including eligibility criteria, how to apply, and what these grants can get you.   

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What are cavity wall insulation grants?

Cavity wall insulation grants are provided by the Great British Insulation Scheme (GBIS) and the Energy Company Obligation (ECO4) to completely cover or reduce insulation costs for qualifying households. 

These wall insulation grants aim to enhance the energy efficiency of low-income and fuel-poor homes, in line with the UK’s ambitious targets to reach net zero carbon emissions by 2050.

The coverage depends on the personal circumstances of the applicant. Applicants must meet a series of eligibility criteria to qualify for assistance, but in most cases will receive free cavity wall insulation. 

More complex installations may sometimes require a financial contribution from the household, but this also depends on their gross income and other factors.

What are the advantages of cavity wall insulation?


Cavity fill insulation exhibits some of the most impressive annual savings in terms of energy bills and domestic CO2 emissions. A detached UK home can save up to £405 in annual energy bills, and cut their annual carbon footprint by a staggering 1.1 tonnes, making this one of the most effective home insulation upgrades on the market. 

Beyond the bills, cavity wall insulation brings about a wealth of other benefits and perks as well. Here are just a few of the improvements you could enjoy with this upgrade:

  • Healthier planet: Insulated homes can retain their internal temperatures far better. This leads to less use of your heating system, effectively reducing your domestic carbon emissions and benefitting the planet in the long run.
  • Healthier home: Damp, drafty homes are a breeding ground for mould and rot. This puts your home's structural integrity at risk, but also greatly harms your health. Mould exasperates respiratory illnesses, and can even harm your immune system. Proper insulation promotes a healthy indoor environment and better indoor air quality.
  • Less maintenance: Of all home insulation upgrades, cavity wall insulation is one of the most straightforward and robust options. With a lifespan of up to 25 years, cavity wall insulation rarely requires maintenance if installed professionally.
  • Boosted investment: Insulation raises your property's value in the housing market. This is due to an increase in your home's Energy Performance Certificate (EPC) rating, a system that tells you how efficient your home is. Homes with higher ratings are valued much higher if you ever plan to rent or sell.
  • Quicker payback: Despite hefty upfront costs, cavity wall insulation leads to some of the highest annual savings of any home insulation upgrade. As such, a household can pay off an initial investment in just about 10 years.

To better visualise the savings one could enjoy with cavity wall insulation, here is our full breakdown of the cost of wall insulation, as well as savings for each type of property in the UK: 

Type of homeAverage installation costs (£)Energy bill savings (£/year)CO2 cuts (kgCO2/year)
Mid-terrace home£1,500£140385
Semi-detached home£2,700£235650
Detached bungalow£2,100£175485
Detached home£4,600£4051,100
This data is from Energy Saving Trust UK and is based on April 2024 estimates. Get a local installer to QUOTE now!

All in all, cavity wall insulation stands out as one of the most cost-effective home insulation projects one could implement, bringing upgrades to your lifestyle, saving you money, and benefitting the planet all in one go.

Are you eligible for free cavity wall insulation?


To know if you are eligible for free cavity wall insulation, you must first meet two key requirements; the eligibility criteria of the grant you apply for, and being a resident of a property suitable for cavity wall insulation.  

There are currently two schemes in the UK providing free cavity wall insulation. These are the Great British Insulation Scheme (GBIS) and the Energy Company Obligation (ECO4). Both schemes have similar qualification criteria and are made to complement each other, but can differ depending on an applicant's circumstances.

Here is a summary of the most general requirements you must meet to qualify for either the GBIS or the ECO4 scheme:

  • Home ownership: To be eligible for a grant scheme, you must either be a homeowner or rent from a private landlord. If you are renting, you will need explicit permission from your landlord to carry out insulation via a grant scheme. This is also the case if you live in social housing.
  • Gross income: As both grant schemes aim to prioritise low-income and fuel-poor homes, applicants in the Low Income Group are very likely to qualify. These are applicants who have a gross annual household income that is less than £31,000.
  • EPC rating: An Energy Performance Certificate (EPC) rating indicates your home's energy efficiency, graded from A (very efficient) to G (very inefficient). Homes with an EPC rating below D (homeowners) or E (home renters) can qualify for assistance.
  • Council tax bands: Council tax bands determine how much council tax you pay based on your property's value. Households in bands A - D for England, or A - E for Scotland and Wales, can qualify for free wall insulation through a grant scheme.
  • Government benefits: Applicants who receive government benefits and allowances are likely to qualify for a grant scheme. A list of recognised benefits class an applicant as part of the Low-Income group in the UK, making them eligible for grants.
Application Tip

It may be self-explanatory, but a home must have cavity walls to qualify for cavity wall insulation. A grant scheme will not cover the building of a cavity wall property. Cavity walls are usually found in homes built after the 1920s and can be identified by looking at the brickwork. If the bricks are evenly spaced, symmetrical, and horizontal, you likely have cavity walls.

The government benefits currently considered eligible for cavity wall insulation grants are:

  • Child Benefit
  • Pension Guarantee Credit
  • Income-related Employment and Support Allowance
  • Income-based Jobseeker's Allowance
  • Income Support
  • Tax Credits (Child Tax Credits and Working Tax Credits)
  • Universal Credit
  • Housing Benefit
  • Pension Credit Saving Credit

Cavity wall insulation grants for pensioners are also possible. Pensioners can also qualify for free cavity wall insulation even if they don’t meet all the eligibility criteria. Age alone isn’t a qualifying factor, but pensioners might qualify as part of the Low Income Group or General Group. The criteria for each group are as follows: 

Low-Income Group

  • You receive a means-tested benefit (e.g. Pension Credit Guarantee).
  • Your home EPC rating is below D (homeowners) or E (home renters).
  • Your annual gross income is below £31,000.
  • You live in social housing and are vulnerable to the cold (age can be a factor).

General Group

  • You are within council tax bands A - D (England) or A - E (Scotland & Wales).
  • You have a medical diagnosis that can be exasperated by poor insulation.
  • You reside with a child aged under 5 or a resident over the age of 65.
Tip: Local Authority Flex (ECO4 Flex)

If you meet absolutely none of the criteria mentioned so far, hope is still not lost! You may still qualify for a grant through the ECO4 Flex scheme.

This is a household referral program by which your Local Authority (LA) or Devolved Administration (DA) can make a case on your behalf for a grant if they still deem you a vulnerable household.

To learn more about the Authority Flex, visit the official website for the ECO4, or contact your energy provider for more information.

Government grants for cavity wall insulation

The two main government grants for cavity wall insulation in the UK are the Great British Insulation Scheme (GBIS) and the Energy Company Obligation (ECO4). Both grant schemes are active and running until March 2026

Although both grants provide free cavity wall insulation, they also have some key differences with each other:

  • The Great British Insulation Scheme (GBIS) works by delivering a single insulation measure per qualifying household. This is to maximise the reach of the scheme across the UK in an effective manner. To learn more and apply for the scheme, you can visit the official UK government website for more information.
  • Energy Company Obligation (ECO 4) takes a more whole-house approach by offering a combination of upgrades to improve the energy efficiency of each qualifying household. This includes insulation measures, but also energy system repairs, replacements, central heating solutions and other measures. To learn more and apply for this scheme, contact your energy provider directly for more information.

Qualifying applicants will likely get full-cost coverage for all cavity wall insulation types, but in some cases, complex projects might require a financial contribution from the household, depending on personal circumstances.

Cavity wall insulation removal grants


You can also apply for cavity wall insulation removal grants, also known as an extraction grant. This is for households with insulation that no longer meets energy efficiency standards, or is damaged, damp, or rotten.


It’s important to remove any old insulation from your cavity walls before you can install fresh new insulation. Usually, a grant scheme can provide comprehensive coverage for both the extraction of old insulation and the installation of new insulation.

Qualifying for cavity wall insulation removal is a bit more complex. In theory, if insulation by an installer has failed due to a faulty job, then you should be able to directly claim removal from the installer without the need for a grant. 

For cases where this is not an option - such as your installer being out of business - you can file a claim through the Cavity Insulation Guarantee Agency (CIGA), the official UK agency for enforcing cavity wall insulation guarantees. 

The process for filing a claim with CIGA is as follows:

  • Contact CIGA: By visiting the website of CIGA, you can fill out an online claim form and expect a first response back within 2 days. This is the quickest way to get in touch with CIGA, but you can call or email them via their official details.
  • Arrange an inspection: Within the first week of contact, CIGA will arrange a “Complaint Inspection Report” for your property. This assessment is free of charge and will thoroughly look into your reported cavity wall problem.
  • Receive an outcome: Within a month, a decision will be made based on the findings of the property assessment. CIGA will send you a full written report detailing their findings, recommended work, and whether they’re responsible for handling the issue.
  • Begin extraction: If CIGA concludes that your cavity wall insulation needs removing and that they’re responsible for handling it, they will commence remedial works. This will involve the insulation extraction and should take at most 90 days.

It’s also possible to receive cavity wall insulation extraction directly through the ECO4 scheme, however, this grant comes in two parts. The removal of old outdated insulation must be followed up with the installation of brand-new cavity wall insulation. 

Certain requirements must be met to remove cavity wall insulation via ECO4:

  • Guarantees: Any cavity wall insulation in place must either have an expired CIGA guarantee or no CIGA guarantee at all. If CIGA guarantees it, it’s first required to attempt and solve the issue via CIGA.
  • Insurances: Your cavity wall removal must not be covered by any other building or home insurance programmes that are external to ECO4.
  • Recommendations: It’s important to have an inspection conducted, and a recommendation granted by a competent person (Chartered Surveyor) that confirms that existing insulation requires removing to add new insulation.

If these conditions are met, it’s also possible to follow through with cavity wall insulation extraction via the ECO4 scheme, provided that it’s followed up with new insulation.

How can you apply for a cavity wall insulation grant?

To apply for a wall insulation grant, you must first decide which grant scheme you’d like to go ahead with. The GBIS and ECO4 schemes have slight differences in their provisions and eligibility, so make sure to choose what best fits your needs.

The general process for grant application is as follows:

  • Check eligibility: Before applying, make sure you meet most, if not all, of the eligibility criteria for your chosen scheme. This will save you plenty of time in the long run.
  • Get into contact: If you are applying for the GBIS scheme, you can visit the official UK government website to fill out their application form. If you are applying for the ECO4 scheme, you must contact your energy provider directly to learn how to apply.
  • Find the right installer: Once you have been granted eligibility for your chosen grant scheme, a retrofit insulation project will be carried out, in this case, cavity wall insulation.

It’s also important to note that you must work with a professional accredited installer if you plan on applying for a grant scheme. Installers must be PAS 2030-2035 certified, which is a seal of professionalism that is required to obtain grant support. It’s also suggested to get multiple quote prices from various installers to land the best bargain for your home.

However, finding the right professional installer at a favourable price can be a very difficult task. With the sea of installer companies on the market, one could find themselves spending endless hours researching and vetting options on websites and phone calls. That’s where GreenMatch UK comes in to help you! 

By filling out our 30-second simple online form, we’ll send you 3 free home-tailored quotes from our wide-spanning network of trusted installers in your area. The best part? Our services are completely free of charge and come with no obligations to follow through. Click below to begin, and land the best bargain for your home!

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