What the ECO4 Scheme Is and Why It Matters in 2026
The ECO4 scheme (Energy Company Obligation 4) has delivered free or heavily subsidised home energy upgrades to over 300,000 UK households since its launch in April 2022. That makes it one of the largest domestic energy efficiency programmes ever run in Britain. Administered by Ofgem and funded by the UK’s largest energy suppliers, ECO4 targets low-income and fuel-poor households with measures like insulation, heat pumps, and boiler replacements, entirely at no cost to eligible homeowners. With energy bills remaining a significant burden across the country and the scheme extended through to March 2026, understanding exactly how ECO4 works, who qualifies, and what you can get from it has never been more important.
ECO4 replaced the previous ECO3 scheme and introduced a fundamentally different approach. Rather than offering individual measures in isolation, ECO4 requires a whole-house retrofit philosophy, meaning installers must assess your entire home and prioritise the upgrades that will deliver the biggest overall improvement to your property’s energy performance. This shift in approach means that if you qualify, you could receive multiple measures in a single installation, potentially transforming your home’s Energy Performance Certificate (EPC) rating from an F or G up to a C or above.
How ECO4 Works, A Plain English Explanation
The ECO4 scheme operates through a legal obligation placed on large UK energy suppliers, including British Gas, EDF, E.ON, Octopus Energy, and Scottish Power, to fund a set amount of energy efficiency improvements each year. Ofgem sets the targets, energy companies fund the work, and a network of approved installers carries it out. You don’t pay the energy companies directly; the cost is spread across all customers’ bills, which is why ECO4 can offer free measures to those who qualify.
Here’s how the process works in practice:
- Eligibility check, You confirm you meet the income or property criteria (more on these below).
- Application, You apply either directly through an energy supplier, via a government-approved local authority referral, or through an ECO4-registered installer.
- Assessment, A qualified energy assessor visits your home to carry out a full survey and produce a Whole House Plan (WHP).
- Measure selection, Based on the assessment, a package of improvements is proposed. ECO4 prioritises measures that improve the property’s SAP (Standard Assessment Procedure) score the most.
- Installation, Approved contractors carry out the work. All installations must meet PAS 2035 quality standards.
- Sign-off and notification, The installer notifies Ofgem via the system TrustMark registers, and your upgraded EPC is lodged on the national register.
The whole-house approach is a genuine innovation. Under ECO3, a household might receive loft insulation and nothing else. Under ECO4, the same household would receive loft insulation plus cavity wall insulation plus possibly a new heating system, whatever the assessment shows is needed to achieve a meaningful EPC improvement. For properties in EPC bands E, F, and G, the scheme aims to bring them up to at least band D, ideally band C.
ECO4 Eligibility, Who Qualifies in 2026
ECO4 eligibility falls into two main routes: the benefits-based route and the local authority flexible eligibility (LA Flex) route. Understanding both is essential, because many homeowners who assume they don’t qualify actually do via LA Flex.
Benefits-Based Eligibility
You automatically qualify for ECO4 if you or someone in your household receives one of the following:
- Universal Credit (with a net earnings threshold of £31,000 per year or less)
- Income-related Employment and Support Allowance (ESA)
- Income-based Jobseeker’s Allowance (JSA)
- Income Support
- Pension Credit (Guarantee Credit or Savings Credit)
- Working Tax Credit or Child Tax Credit (with income below £16,105 per year)
- Housing Benefit
- Child Benefit (subject to income caps, typically under £31,000)
Local Authority Flexible Eligibility
LA Flex allows local councils to refer households that are fuel-poor or at risk of fuel poverty, even if they don’t receive qualifying benefits. This route accounts for roughly 50% of all ECO4 measures delivered. Councils use their own criteria, which might include low household income, high energy costs relative to income, or living in a property with very poor energy efficiency, to make referrals. If you’re on a low income but not on benefits, or if your property is in a particularly poor condition, contact your local council’s housing team to ask about LA Flex referrals.
Property Eligibility
ECO4 measures are available to both homeowners and private renters, though for rented properties the landlord must consent. The property must be in England, Scotland, or Wales. Social housing is generally excluded. There’s no specific age requirement for the property itself, but the EPC must show room for significant improvement, properties already at EPC band C or above are unlikely to qualify unless the heating system is inadequate.
What Measures Are Available Under ECO4
The range of measures available under ECO4 is broader than many homeowners realise. The scheme covers both insulation and heating improvements, and in most cases a successful application results in more than one measure being installed.
| Measure Type | Description | Typical SAP Score Improvement | Availability Under ECO4 |
|---|---|---|---|
| Loft Insulation | 200–270mm of mineral wool or blown insulation installed in accessible loft spaces | +5 to +10 points | Yes, very common |
| Cavity Wall Insulation | Injected insulation into unfilled cavity walls of standard brick or block construction | +8 to +15 points | Yes, very common |
| Solid Wall Insulation (Internal) | Insulated plasterboard or framing fixed to inner face of solid walls | +15 to +25 points | Yes, for eligible solid-wall properties |
| Solid Wall Insulation (External) | Insulated render or cladding applied to the outside of the building | +15 to +25 points | Yes, subject to planning and suitability |
| Air Source Heat Pump | Replaces gas or electric heating with a highly efficient heat pump system | +20 to +40 points | Yes, increasingly prioritised from 2024 onwards |
| Gas Boiler Replacement | New high-efficiency condensing boiler where heat pump is not suitable | +5 to +15 points | Limited, only where heat pump unsuitable |
| First Time Central Heating | Installation of full central heating in properties with no existing system | +25 to +40 points | Yes |
| Underfloor Insulation | Insulation beneath suspended timber or solid floors | +3 to +8 points | Yes, as secondary measure |
| Flat Roof and Room-in-Roof Insulation | Specialist insulation for non-standard roof structures | +5 to +12 points | Yes |
| Solar PV Panels | Photovoltaic panels generating on-site renewable electricity | +10 to +20 points | Yes, where combined with heat pump |
Gas boiler replacements have been increasingly restricted under ECO4, with the scheme steering eligible households towards heat pumps wherever the property and location make them viable.
How Much Does the ECO4 Scheme Cost in 2026
For eligible households, the core principle of ECO4 is free installation, you should not be charged for measures approved under the scheme. However, the reality is slightly more nuanced. Some households may be asked to contribute a “top-up” payment if they want a measure that goes beyond what the ECO4 funding covers, or if their property requires additional preparatory work. This is legal under the scheme rules but should always be clearly explained in writing before work begins.
The table below shows the typical market value of common ECO4 measures, i.e., what you would pay if you were having these installed privately, compared to what an ECO4-eligible household receives.
| Measure | Typical Private Cost (2026) | ECO4 Customer Cost | Average Annual Bill Saving |
|---|---|---|---|
| Loft Insulation (semi-detached, 270mm) | £300 – £600 | Free | £150 – £280 per year |
| Cavity Wall Insulation (3-bed semi) | £700 – £1,400 | Free | £200 – £400 per year |
| Internal Solid Wall Insulation (3-bed terrace) | £7,500 – £13,000 | Free (or small top-up) | £300 – £500 per year |
| External Solid Wall Insulation (3-bed semi) | £10,000 – £18,000 | Free (or top-up likely) | £300 – £500 per year |
| Air Source Heat Pump (average 3-bed home) | £10,000 – £15,000 installed | Free for fully eligible households | £500 – £1,200 per year (vs electric) |
| First Time Central Heating System | £3,500 – £6,000 | Free | £400 – £800 per year (vs electric panel heaters) |
| Solar PV (4kWp system) | £6,000 – £9,000 | Partial funding; top-up likely | £400 – £600 per year |
| Underfloor Insulation | £800 – £2,500 | Free (secondary measure) | £50 – £130 per year |
If you are asked to make a top-up contribution, get at least two quotes and make sure any payment is properly invoiced. Reputable installers will not ask for large upfront payments before work starts. The scheme does not cover cosmetic reinstatement beyond standard finishing, so if you have particularly expensive wallpaper, for example, you may need to factor in redecorating costs after internal wall insulation.
Benefits of ECO4, The Real-World Impact
The benefits of ECO4 go significantly beyond the obvious fact that the work is free. The scheme’s whole-house approach means eligible households see substantially larger improvements than any single measure could deliver on its own.
Energy Bill Reductions
According to the Department for Energy Security and Net Zero (DESNZ), households that receive a comprehensive package of ECO4 measures see average annual energy bill savings of between £400 and £1,000 per year, depending on property size, existing energy use, and the measures installed. For households in particularly inefficient homes, EPC bands F and G, savings can exceed £1,500 per year when combined with a heat pump and solid wall insulation.
EPC Rating Improvements
ECO4 is explicitly built to improve EPC ratings. The scheme targets a minimum improvement of at least two EPC bands for properties starting at band E, F, or G. A property moving from EPC band G to band D, for instance, could see its assessed heating costs fall from over £3,200 per year to under £1,400, a saving of over £1,800 annually on paper, with real-world savings typically 60–70% of the assessed figure.
Property Value
Research from the Nationwide Building Society and multiple academic studies consistently shows that an EPC band improvement of one to two levels can increase property value by 1.7% to 5%. For an average UK home worth £285,000, that’s an additional £4,800 to £14,250 in value, achieved at no direct cost to you.
Comfort and Health
Cold, damp homes are directly linked to respiratory illness, cardiovascular disease, and mental health problems. ECO4-funded improvements reduce heat loss, eliminate cold spots, and decrease the risk of condensation and mould, all of which contribute to measurably better health outcomes, particularly for elderly residents and children.
Carbon Reduction
Ofgem’s ECO4 obligation requires energy suppliers to collectively deliver a minimum of 13 megatonnes of lifetime carbon savings over the scheme period. Individual households typically see a reduction of 1.5 to 3.5 tonnes of CO2 per year after a full package of measures, equivalent to taking a small car off the road entirely.
How to Choose the Right Installer for ECO4 Work
Choosing the right installer is arguably the most important decision in the ECO4 process. Because the work is free to you, it can be tempting to simply accept the first offer that comes through the door, but the quality of installation varies significantly, and a poor installation can cause problems for decades.
Key Accreditations to Look For
- TrustMark registration, All ECO4 installers must be registered with TrustMark, the government-endorsed quality scheme. You can verify any installer at trustmark.org.uk.
- MCS certification, Required for heat pump and solar PV installations. MCS-certified installers meet strict technical standards and must issue a warranty.
- PAS 2035 compliance, The British Standard for retrofit work. Every ECO4 project must follow this framework, which includes a Retrofit Assessor, Retrofit Coordinator, and approved installer working as a team.
- CHAS or Constructionline, Additional health and safety accreditations that reputable contractors often hold.
Red Flags to Avoid
- Cold callers claiming you are “definitely eligible” without checking your details
- Requests for large cash payments upfront
- No written specification or Whole House Plan provided before work starts
- Pressure to sign documentation quickly or claims that “the offer expires today”
- Installers who cannot provide their TrustMark registration number on request
The energy company funding your measures may appoint an installer directly, but you have the right to request a different TrustMark-registered contractor if you have concerns. Don’t be afraid to ask for references, check online reviews, and verify accreditations independently before agreeing to any work.
ECO4 Installation, What to Expect Step by Step
Once your application has been accepted and an installer appointed, the installation process follows a defined sequence under the PAS 2035 framework. Knowing what to expect helps you ask the right questions and ensures the work is done properly.
- Retrofit Assessment, A qualified Retrofit Assessor visits your home. This typically takes 1.5 to 2.5 hours. They inspect the fabric of the building (walls, roof, floor, windows), the heating system, ventilation, and any existing energy improvements. They produce a formal assessment report.
- Whole House Plan, A Retrofit Coordinator produces a Whole House Plan based on the assessment. This document sets out a sequenced plan of measures, some to be installed under ECO4 now, some potentially for the future. You should receive and review this plan before any work begins.
- Pre-installation survey, For specific measures, a more detailed survey may be needed. For cavity wall insulation, for example, a drill test and wall inspection confirms the cavities are suitable. For heat pumps, a heat loss calculation is mandatory.
- Scheduling, Work is scheduled at a time that suits you. Most insulation measures are completed in a single day. Heat pump installation typically takes 2–3 days. Solid wall insulation can take 5–10 days depending on the property size and whether it’s internal or external.
- Installation, The approved contractor carries out the work. All waste materials should be removed from site. For heat pumps, this includes commissioning the system and demonstrating it to you.
- Handover documentation, You should receive certificates for all work completed, including Building Regulations compliance where applicable (required for heat pumps and new heating systems), MCS certificates, and any product warranties.
- Post-installation inspection, Under PAS 2035, a proportion of all ECO4 installations are subject to independent quality inspections. If yours is selected, an independent assessor will visit to verify the work meets the required standard.
- Updated EPC, A new EPC should be lodged on the national register reflecting your home’s improved energy performance. Check this has been completed at epcregister.com.
Grants and Funding That Work Alongside ECO4
ECO4 is the largest but not the only government energy efficiency funding stream available to UK homeowners in 2026. Understanding how other schemes interact with ECO4 can help you access additional support, particularly if you don’t fully qualify for ECO4 or if you want to go further than ECO4 alone covers.
The Great British Insulation Scheme closed on 31 March 2026. It funded insulation measures only and never covered windows or glazing. The Great British Insulation Scheme closed on 31 March 2026. It funded insulation measures only and never covered windows or glazing.
The Boiler Upgrade Scheme (BUS) offers grants of £7,500 for air source heat pumps and £7,500 for ground source heat pumps to homeowners in England and Wales who don’t qualify for ECO4. If your income is above the ECO4 threshold but you want to install a heat pump, BUS is likely your best route.
The Home Upgrade Grant (HUG2) targets low-income households in off-gas-grid properties in England, similar in intent to ECO4 but administered through local authorities rather than energy companies. If you heat your home with oil, LPG, or electric storage heaters and your local authority is participating, HUG2 may offer additional or alternative funding.
The Warm Home Discount is not an installation grant but provides a £150 rebate on electricity bills for eligible low-income households, it can be claimed simultaneously with ECO4 and provides immediate short-term relief while longer-term measures are installed.
Common Problems With ECO4 and How to Avoid Them
Despite the scheme’s good intentions, ECO4 is not without its challenges. Being aware of the most common issues means you can take steps to protect yourself.
Cavity Wall Insulation Problems
Cavity wall insulation, when installed in unsuitable properties, can lead to damp ingress and condensation, a significant and costly problem. Walls that are exposed to driving rain, have existing damp issues, or have non-standard cavity widths may not be suitable. Always ensure a proper pre-installation survey is carried out and that the installer checks for existing moisture before proceeding. If you experience damp after installation, report it immediately to your installer, TrustMark, and your energy supplier.
Cold Calling and Scams
The ECO scheme has attracted a persistent problem with fraudulent cold callers who claim to offer “free government grants” and then carry out substandard work or charge hidden fees. Never accept work from unsolicited callers. Always verify an installer’s TrustMark registration number independently before agreeing to anything.
Incomplete Installations
Some households have reported receiving partial measures, for example, loft insulation installed without the accompanying cavity wall insulation that the assessment recommended. This may be due to funding constraints at the installer level. If your Whole House Plan specified multiple measures, push for all of them to be delivered. If the installer refuses, escalate to your energy supplier or contact Ofgem.
Ventilation Issues After Insulation
Sealing a home tightly against heat loss can inadvertently reduce ventilation, leading to condensation, mould, and poor indoor air quality. Under PAS 2035, Retrofit Coordinators are supposed to assess ventilation as part of the Whole House Plan and specify additional ventilation measures (such as extractor fans or trickle vents) where needed. Ask explicitly whether ventilation has been assessed and whether any supplementary measures are recommended.
Disputes and Complaints
If you have a problem with ECO4 work, the first step is to raise a formal complaint with the installer. If unresolved, escalate to the energy supplier funding the work. TrustMark also operates a Consumer Code dispute resolution process. Ofgem has powers to investigate non-compliance by energy suppliers and can be contacted if you believe the scheme rules have been breached.
Maintenance After ECO4 Measures Are Installed
ECO4 improvements are largely low-maintenance, but a small amount of attention will ensure they continue to perform well for decades.
- Loft insulation, Check annually that insulation hasn’t been disturbed by loft access, pests, or water ingress. Keep the loft hatch well insulated and sealed. Properly installed mineral wool loft insulation has a lifespan of 40+ years with no active maintenance required.
- Cavity wall insulation, No ongoing maintenance required, but monitor for signs of damp on internal walls, particularly after periods of heavy rain. Ensure external rendering and pointing remains intact to prevent moisture entering the cavity.
- Air source heat pumps, Annual servicing by a qualified engineer is recommended (and often required to maintain the manufacturer’s warranty). Keep the external unit clear of debris, vegetation, and ice. Check that the refrigerant circuit is inspected every 12 months by an F-Gas registered engineer.
- Solar PV panels, Panels are largely self-cleaning in the UK climate, but an occasional rinse with water and a check of mounting fixings every 2–3 years is sensible. Have the inverter inspected every 5 years. Panels typically carry a 25-year performance warranty.
- New boilers, Annual Gas Safe service is essential for safety, efficiency, and warranty compliance. Bleed radiators annually and check system pressure monthly.
How to Apply for ECO4 in 2026
There are three main routes to applying for ECO4, and the best one depends on your circumstances:
- Apply directly through your energy supplier, Contact your current energy supplier (or any of the big six) and ask about ECO4. Most have dedicated phone lines and online application portals. This route is most efficient if you’re clearly eligible on benefits grounds.
- Apply through your local authority, Contact your council’s housing or energy team and ask about LA Flex referrals. This is the best route if you’re fuel-poor but not claiming qualifying benefits. Your council may also be running its own referral programme in partnership with approved installers.
- Contact an Ofgem-registered ECO4 installer directly, Many registered installers handle the entire application process on your behalf. Search the TrustMark database or the Ofgem ECO register at ofgem.gov.uk to find registered contractors in your area.
When you apply, have the following ready: proof of benefits (or low income), your current EPC rating if you have it, your council tax reference, and details of your property type and construction. The assessment and application process, from first contact to installation start, typically takes 6 to 16 weeks, so apply as early as possible, particularly as the scheme’s March 2026 deadline approaches.
ECO4 is a rare opportunity for eligible households to receive thousands of pounds worth of genuine home improvements at no direct cost. With energy prices expected to remain elevated and the UK’s housing stock one of the leakiest in Europe, the improvements it funds deliver lasting value, reduced bills, higher comfort, better health outcomes, and a more valuable property, that will still be paying dividends long after the scheme itself has closed.
