Wales is fully covered by the UK Government’s Energy Company Obligation Phase 4 (ECO4) scheme. Whether you own your home or rent privately, you could qualify for fully funded energy efficiency improvements, including insulation upgrades, heating systems, and air source heat pumps, at no cost to you. Welsh households also benefit from the Welsh Government’s own Warm Homes Programme, known as Nest, which runs alongside ECO4 and provides an additional route to free home improvements for eligible residents.
This guide explains how both schemes work in Wales, who qualifies, what improvements are available, and how to apply before the December 2026 deadline.
Summary: ECO4 is a UK-wide scheme that covers Wales. Eligible Welsh households can receive fully funded insulation, heating, and renewable energy improvements through ECO4 and, separately, through the Welsh Government’s Nest scheme. ECO4 runs until 31 December 2026.
What Is the ECO4 Scheme in Wales?
ECO4, short for Energy Company Obligation Phase 4, is a programme that places a legal obligation on the UK’s largest energy suppliers to fund energy efficiency improvements in eligible homes across England, Scotland, and Wales. It does not cover Northern Ireland, which has its own separate arrangements.
The scheme launched in April 2022 and was extended by nine months following a government consultation. The new end date, confirmed by the Department for Energy Security and Net Zero (DESNZ) on 23 January 2026, is 31 December 2026. There will be no further extension and no successor supplier obligation after ECO4 ends.
In Wales, the scheme is particularly important. The country has a high proportion of older, solid-wall properties, many in rural areas not connected to the gas grid. These homes are among the hardest and most expensive to heat, which makes ECO4 funding a meaningful source of support.
ECO4 Wales Eligibility
There are two routes to ECO4 eligibility in Wales: a standard route based on qualifying benefits, and a discretionary route administered by local councils, known as ECO4 Flex.
Standard Eligibility: Benefits-Based Criteria
To qualify through the standard route, at least one person in your household must receive one of the following benefits:
- Universal Credit
- Pension Credit (Guarantee Credit or Savings Credit)
- Income-based Jobseeker’s Allowance (JSA)
- Income-related Employment and Support Allowance (ESA)
- Income Support
- Working Tax Credit
- Child Tax Credit
- Housing Benefit
- Child Benefit (subject to household income thresholds)
Child Benefit Income Thresholds
If Child Benefit is the only qualifying benefit received, household income must fall below the following limits:
| Number of Children | Single Claimant | Member of a Couple |
| 1 | £19,900 | £27,500 |
| 2 | £24,800 | £32,300 |
| 3 | £29,600 | £37,200 |
| 4 or more | £34,500 | £42,000 |
Property Requirements
In addition to the benefit criteria, the property must have an Energy Performance Certificate (EPC) rating of D, E, F, or G. The improvements funded through ECO4 must raise the property’s energy rating by at least two SAP bands, to a D or above. Homeowners and private tenants can both apply. Tenants require their landlord’s written consent before any works can proceed.
ECO4 Flex Wales: The Discretionary Route
Not everyone who needs support will receive one of the standard qualifying benefits. ECO4 Flex, also referred to as Local Authority Flex (LA Flex), allows Welsh councils to refer households that fall outside the standard criteria but are still in genuine need.
In Wales, councils can use several proxy criteria to assess eligibility, including the Welsh Index of Multiple Deprivation. Households in the most deprived areas of Wales, those with a council tax reduction due to low income, residents with chronic health conditions worsened by cold homes, and families with children eligible for free school meals may all qualify under this route.
Contact your local council directly to find out whether they participate in ECO4 Flex and what their specific eligibility criteria are. Availability and funding under this route can vary by area.
What Improvements Are Funded Under ECO4 in Wales?
ECO4 takes a whole-house retrofit approach, meaning the improvements are designed to raise the overall energy performance of a property rather than address a single issue in isolation. The measures available include:
- Loft insulation
- Cavity wall insulation
- Solid wall insulation (internal or external)
- Room-in-roof insulation
- First-time central heating installation
- Air source heat pumps
- Modern heating controls and smart thermostats
- Solar panels (in some cases)
Wales has a significant number of older stone-built properties that lack cavity walls. Solid wall insulation is therefore a particularly relevant measure for rural Welsh communities and historic housing stock. For properties off the gas grid, first-time central heating using an air source heat pump is a common outcome.
All installations must be carried out by TrustMark-accredited installers who comply with PAS 2035, the UK standard for retrofit work.
The Warm Homes Programme (Nest): Wales-Specific Support
Alongside ECO4, Welsh households benefit from an additional layer of support provided directly by the Welsh Government. The Warm Homes Programme, delivered through its Nest service, has been running since 2011 and has provided free home energy improvements to over 60,000 households across Wales, with total Welsh Government investment exceeding £251 million.
On 1 April 2024, Nest was relaunched with a stronger focus on low-carbon technologies, reflecting Wales’s ambition to become net zero by 2050. The updated scheme individually assesses each property and recommends the most suitable improvements, which may include insulation, heat pumps, or solar panels.
Nest is open to homeowners and private tenants in Wales. To qualify for free improvements (rather than advice only), you or someone in your household must receive a means-tested benefit, and your property must typically have an EPC rating of E, F, or G. Households where a member has an eligible health condition and an EPC rating of D may also qualify, subject to income thresholds.
Fuel Poverty in Wales: The Scale of the Challenge
The importance of ECO4 and Nest in Wales is underlined by official fuel poverty statistics published by the Welsh Government. According to modelled estimates based on October 2024 data, 340,000 households in Wales (25%) were living in fuel poverty. A further 215,000 households (16%) were estimated to be at risk of fuel poverty, and 63,000 households (5%) were in severe fuel poverty.
In Wales, a household is defined as fuel poor if it would need to spend more than 10% of its total household income on maintaining a satisfactory heating regime. Single pensioner households are disproportionately affected: 43% of this group were estimated to be fuel poor in 2024.
These figures reflect the reality for households across Wales, where some of the UK’s oldest and least efficient housing stock combines with lower average incomes to make keeping a home warm genuinely unaffordable for a significant portion of the population.
How to Apply for ECO4 in Wales
Applying for ECO4 in Wales is a straightforward process delivered through accredited installers rather than a central government portal. Here is what to expect:
- Complete the application form on ECO4.co.uk to check your initial eligibility.
- A member of the team will contact you to discuss your circumstances and confirm next steps.
- An accredited assessor will carry out a free property survey to evaluate your current EPC rating, insulation levels, and heating system.
- The assessor will recommend the most suitable measures for your property based on the survey findings.
- Once approved, qualified installers will carry out the work. All costs are covered for eligible households.
What Happens When ECO4 Ends?
ECO4 will close permanently on 31 December 2026. The government has confirmed there will be no ECO5 scheme and no successor supplier obligation. For England, the primary replacement is the Warm Homes Local Grant. This scheme is administered by local councils in England and does not apply to Wales.
Welsh households will continue to be served by the Nest scheme under the Warm Homes Programme, which remains the Welsh Government’s primary mechanism for tackling fuel poverty beyond the ECO4 deadline. If you believe you may be eligible, it is strongly advisable to apply for ECO4 now rather than wait. Installer capacity fills up in the months before major scheme deadlines, and once energy suppliers have met their individual targets, they are under no obligation to fund further installations, even before December 2026.
Conclusion
ECO4 is fully available in Wales and represents a significant opportunity for eligible households to receive free insulation, heating, and renewable energy upgrades before the scheme closes in December 2026. Welsh residents also benefit from the additional support provided by the Welsh Government’s Nest scheme, which runs alongside ECO4 and offers its own route to free home improvements for qualifying households.
With one in four Welsh households estimated to be living in fuel poverty, the need for these programmes is clear. If you own your home or rent privately in Wales, receive a qualifying benefit, and live in a property with an EPC rating of D, E, F, or G, you could qualify for fully funded improvements that make your home warmer, cheaper to run, and better for the environment.
Apply through ECO4.co.uk to find out whether you are eligible.