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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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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.
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:
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 home | Average installation costs (£) | Energy bill savings (£/year) | CO2 cuts (kgCO2/year) |
---|---|---|---|
Flat/Apartment | £1,000 | £110 | 305 |
Mid-terrace home | £1,500 | £140 | 385 |
Semi-detached home | £2,700 | £235 | 650 |
Detached bungalow | £2,100 | £175 | 485 |
Detached home | £4,600 | £405 | 1,100 |
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.
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:
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:
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
General Group
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.
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.
The UK Government is set to unveil the Warm Homes Plan in spring 2025. This initiative aims to accelerate the shift to a low carbon future by replacing existing grant programs with a unified funding approach.
Beginning on April 1, 2025, and projected to last for 3 to 5 years, the plan will be implemented by local authorities. The scheme offers two primary types of support:
The Warm Homes Plan aims to significantly enhance the energy efficiency and sustainability of UK homes.
Although both grants provide free cavity wall insulation, they also have some key differences with each other:
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.
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:
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:
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.
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:
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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It’s possible to still get grants for cavity wall insulation through either the Great British Insulation Scheme (GBIS) or the Energy Company Obligation (ECO4) until March 2026. In any case, it’s best to apply as early as possible to increase your chances of qualifying in time.
Insulating cavity walls is a great home upgrade that comes with a wealth of benefits. Alongside cutting your home’s heat loss by up to 33%, cavity wall insulation in a detached home can bring up to £405 in energy bills, and 1.1 tonnes in domestic CO2 cuts every year.
You can claim compensation for cavity wall insulation through either the GBIS or ECO4 grant scheme, given that you meet the eligibility criteria. If you do not meet the criteria required, you might be able to get some grant coverage through the ECO Flex program administered by the ECO4 scheme.
Cavity wall insulation in a standard 3-bedroom semi-detached UK home costs around £2700. Naturally, this cost depends on your home size, location, installation difficulty, and whether there is any existing insulation in place that requires removal.
Akif is a copywriter at GreenMatch since 2023. With a keen interest in community sustainability, green solutions and the role of digital media in identifying climate trends, he aims to hone in on his background in International Studies and Digital Media to provide a multidisciplinary approach to written content rooted in credible research and accuracy.
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