The Energy Company Obligation 4 — commonly known as ECO4 — is the UK government's flagship scheme for delivering free energy efficiency improvements to low-income and vulnerable households. Running from April 2022 to March 2026, it places a legal obligation on the largest energy suppliers to fund upgrades that reduce energy bills and carbon emissions. If your home is poorly insulated, relies on an inefficient heating system, or receives certain means-tested benefits, you may be entitled to significant improvements at no cost to you.
What Is the ECO4 Scheme?
ECO4 is the fourth iteration of the Energy Company Obligation programme, which has been running in various forms since 2013. Under the scheme, energy suppliers with more than 150,000 domestic customers are required to meet energy-saving targets by funding improvements in eligible homes. Unlike previous phases, ECO4 takes a whole-house approach: rather than installing a single measure in isolation, assessors look at the home as a system and recommend a package of upgrades that work together. This means a household might receive both cavity wall insulation and a new heat pump in the same referral, rather than one or the other.
Who Is Eligible for ECO4?
Eligibility for ECO4 is determined by two main criteria: household income and the energy performance of the property. To qualify, you generally need to meet at least one of the following conditions.
- You receive a qualifying means-tested benefit, such as Universal Credit, Pension Credit, Child Tax Credit, Working Tax Credit, Housing Benefit, Income Support, Income-based Jobseeker's Allowance, or Income-related Employment and Support Allowance.
- A child under 16 in the household receives Child Benefit and household income falls below a defined threshold (which varies by family size).
- Your home has an Energy Performance Certificate (EPC) rating of D, E, F, or G — indicating it is among the least energy-efficient properties.
- You have been referred through the ECO4 Flex route, where local authorities can extend eligibility to households in fuel poverty that do not receive qualifying benefits.
What Measures Can ECO4 Fund?
ECO4 covers a broad range of energy efficiency and heating measures. The exact combination installed depends on what the property needs and what will achieve the greatest improvement in its EPC rating. Commonly funded upgrades include the following.
- Loft insulation and top-up loft insulation
- Cavity wall insulation
- Solid wall insulation (internal or external)
- Underfloor insulation
- Air source heat pumps, replacing inefficient gas or oil boilers
- Biomass boilers in rural areas without access to the gas grid
- First-time central heating systems in homes currently relying on room heaters
- Smart heating controls
- Solar photovoltaic (PV) panels, in some cases as part of a package
How Does ECO4 Differ From Previous ECO Phases?
Earlier phases of the scheme, particularly ECO3, permitted energy companies to fund boiler replacements including gas boiler upgrades. ECO4 deliberately moves away from fossil fuel heating. Gas boiler replacements are no longer an eligible measure under the standard ECO4 rules. Instead, the scheme prioritises low-carbon heating such as heat pumps and, where appropriate, biomass boilers. This shift reflects the UK's legally binding commitment to reach net zero by 2050 and the role that domestic heating — currently responsible for a significant share of the country's carbon emissions — must play in that transition.
How to Apply for ECO4
There is no single central application portal for ECO4. The process typically begins with one of the following routes.
- Contact your energy supplier directly. All major suppliers participating in the scheme — including British Gas, E.ON, EDF, Octopus Energy, OVO, and others — have dedicated ECO teams. They will carry out an initial eligibility check and, if you qualify, arrange a home survey.
- Use a government-registered ECO4 installer or managing agent. Many MCS-certified installers and energy companies work as managing agents, handling referrals on behalf of suppliers. A brief phone consultation is usually enough to begin the process.
- Apply through your local authority via the ECO4 Flex route. Contact your council's housing or energy efficiency team to ask whether they operate a local flex scheme and how to be referred.
Once a referral is accepted, a surveyor will visit your home to assess its current energy performance and identify which measures are appropriate. The survey is free. If the property qualifies, the installing company will arrange the works at no cost to you.
The Role of MCS Certification in ECO4 Installations
Not every contractor is permitted to carry out ECO4-funded work. Installers must be certified under the relevant quality assurance framework for the measure being installed. For heat pumps — one of the primary technologies promoted under ECO4 — MCS (Microgeneration Certification Scheme) certification is a mandatory requirement. MCS certification means the installer has been independently assessed against recognised standards for both the technology they install and the quality of their workmanship. It also means the equipment itself meets minimum performance standards. When you are contacted by a company offering ECO4 work, always verify that they hold the appropriate certification for the specific measure they are proposing.
ECO4 and Other Available Schemes
ECO4 sits alongside several other government programmes, and in some cases households can benefit from more than one scheme. The Great British Insulation Scheme (GBIS), launched in 2023, targets a broader group of households — including those in the lower council tax bands — and focuses specifically on a single insulation measure rather than the whole-house approach of ECO4. For households above the ECO4 income thresholds who wish to install a heat pump or biomass boiler, the Boiler Upgrade Scheme offers a grant of up to £7,500 towards an air or ground source heat pump, or up to £5,000 towards a biomass boiler. These schemes are not mutually exclusive in all cases, and a local installer or energy advisor can help identify the best combination for your situation.
Common Questions About ECO4
- Does ECO4 cover rented properties? Yes. Both private and social rented homes can qualify, but the landlord's agreement is required before works can proceed. Landlords cannot be asked to contribute to the cost for eligible tenants.
- Will I need to repay the grant if I sell my home? No. ECO4 funding is a grant, not a loan. There is no repayment obligation if you move.
- How long does the installation take? This varies by measure. Loft insulation can typically be completed in a day. Heat pump installations are more involved and may take several days, including a design survey and any necessary adjustments to the heating distribution system.
- Is ECO4 available in Scotland and Wales? The scheme applies across Great Britain. Scotland and Wales also have their own additional programmes — Home Energy Scotland and Nest Warm Homes Wales respectively — which can supplement ECO4 funding.
If your home is draughty, expensive to heat, or you are struggling with energy bills, it is worth checking your ECO4 eligibility before the scheme closes in March 2026. A free home assessment carried out by an approved, MCS-certified installer is the simplest starting point — it costs nothing, commits you to nothing, and may result in thousands of pounds of improvements being funded in full. Use the Renovation Register to find MCS-certified heat pump and insulation installers working in your area, and ask them directly whether they can initiate an ECO4 referral on your behalf.
