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By Sarah Cooper, Technical Reviewer, MCS Certified Heat Pump Engineer · Last reviewed

ECO4 Flex 2026: Free or Low-Cost Heat Pumps UK Guide

First published
UK terraced homes that may qualify for an ECO4 Flex funded heat pump

TL;DR

  • ECO4 Flex is not a separate grant. It is a route into the main ECO4 scheme that lets your local council set its own eligibility rules, so you can qualify without being on benefits.
  • Households earning under roughly £31,000 are commonly accepted under LA Flex, though every council publishes its own Statement of Intent with local income and vulnerability criteria.
  • A funded heat pump under ECO4 usually means air source, with 100% funding for the pump in many cases, but you may need to top up for extra work such as radiators or a hot water cylinder.
  • Your home needs a low EPC (typically D to G) and enough insulation to run a heat pump well. ECO4 can sometimes fund the insulation first.
  • You apply through your council or an ECO4 installer, not directly to gov.uk. The scheme is scheduled to run until 31 March 2026, so timing matters.

Updated July 2026.

In 2026 a lot of UK households sit in an awkward gap. They earn too much to claim means-tested benefits, but not enough to comfortably spend £8,000 or more on a heat pump. ECO4 Flexible Eligibility, usually shortened to ECO4 Flex or LA Flex, exists to close that gap. It hands local councils the power to nominate households for funded energy efficiency work, including air source heat pumps, based on local judgement rather than a national benefits checklist.

The confusion is understandable. ECO4 Flex is talked about as if it were its own scheme, but it is really a side door into the same Energy Company Obligation that funds the standard route. This guide explains what ECO4 Flex actually is, who qualifies in 2026, how it compares with the Boiler Upgrade Scheme, and the exact steps to apply before the scheme closes. I have surveyed enough homes to know that the funding is only half the story, so I will also cover what a heat pump needs from your property to work once it is installed.

Table of Contents

What ECO4 Flex Actually Is

ECO4 is the fourth phase of the Energy Company Obligation, the government scheme that forces larger energy suppliers to pay for efficiency improvements in low income and vulnerable homes. The main route qualifies households automatically if someone receives a qualifying benefit such as Universal Credit or Pension Credit. ECO4 Flexible Eligibility is the part of that scheme where local authorities can nominate households who do not receive those benefits but still live in a cold, expensive to heat home.

In plain terms, ECO4 Flex lets your council vouch for you. Each local authority publishes a document called a Statement of Intent that sets out the local rules it will use. Once your council declares you eligible, an installer working with an obligated energy supplier can deliver measures under the same ECO4 funding pot. The full framework sits with the regulator, and you can read the scheme structure on the Ofgem ECO pages.

The important passage to remember is this. ECO4 Flex is a qualification route, not a pot of money of its own. The funding, the measures and the quality rules are identical to standard ECO4. What changes is only how you prove you deserve it.

Why the Government Created a Flexible Route

The benefits based route misses a large group of struggling households. Pensioners on modest private incomes, self employed people with low take home pay, and families just above the benefit threshold all live in leaky homes but fail the automatic test. Flexible Eligibility was designed to catch them. Councils know their own housing stock and can target streets of solid wall Victorian terraces or off gas rural homes that suffer the highest bills.

Who Qualifies for ECO4 Flex in 2026

There is no single national income figure, because the whole point of Flex is local discretion. That said, a few criteria appear in almost every council Statement of Intent. Most authorities use one or more of these gateways.

  • Low income. A common threshold is a gross household income under roughly £31,000 a year. Some councils set it lower, some adjust it for household size.
  • Health conditions made worse by cold. Households with a resident who has a respiratory, cardiovascular or limited mobility condition are frequently prioritised.
  • NHS or local referral. Some areas accept referrals from health services or debt advice charities.
  • Proxy targeting (LA Flex routes). Councils can use data such as postcode deprivation indices to identify eligible streets.

The property side matters just as much as the household side. To receive a heat pump under ECO4 your home usually needs an EPC rating of D, E, F or G, because the scheme is aimed at inefficient homes. You can check the eligibility gateways for the wider scheme on the gov.uk ECO4 eligibility page.

The single most useful thing you can do is read your own council's Statement of Intent. Search the name of your local authority followed by ECO4 flexible eligibility statement of intent. That document tells you the exact income limit, the vulnerability criteria and how to submit a declaration in your area.

A Quick Self Check

Before you apply, run through this short list. If you tick two or more, ECO4 Flex is worth pursuing:

  1. Your annual household income is under about £31,000.
  2. Your home has an EPC of D or below, or has never had one.
  3. Someone in the home has a long term health condition affected by cold.
  4. Your home is off the gas grid or heated by an old boiler, electric storage heaters or oil.

ECO4 Flex vs Standard ECO4 vs the Boiler Upgrade Scheme

Homeowners often mix these up, then apply for the wrong one and lose weeks. Here is how the three routes compare in 2026.

FactorStandard ECO4ECO4 Flex (LA Flex)Boiler Upgrade Scheme
How you qualifyOn a means tested benefitNominated by your councilAny homeowner, no income test
Typical cost to youOften £0 for an air source pumpOften £0, top ups possible£7,500 grant, you pay the rest
Income limitBenefit dependentAround £31,000, set locallyNone
EPC requirementLow EPC (D to G)Low EPC (D to G)No EPC condition beyond loft and cavity insulation
Extra measures fundedInsulation, radiators possibleInsulation, radiators possibleHeat pump only
Scheme end date31 March 202631 March 202631 March 2028

The takeaway is simple. If you can be nominated under Flex, it is almost always the cheapest route because it can cover the whole install rather than leaving a bill. If your income is comfortably above the local cap, the Boiler Upgrade Scheme £7,500 grant is your realistic option instead. Our fuller breakdown of the standard benefits route lives in the ECO4 free heat pump guide, and the grant mechanics are covered in the Boiler Upgrade Scheme complete guide.

Different Nations, Different Schemes

ECO4 and its Flex route run UK wide, but each nation layers its own support on top. Scottish households should also look at Home Energy Scotland support, covered in our Scotland heat pump grants guide. Welsh households have the Nest scheme, explained in the Wales heat pump grants guide. Read the national option alongside ECO4 Flex, because you cannot always stack them but you can choose the more generous one.

What "Free" Really Covers Under ECO4 Flex

The word free does a lot of heavy lifting in this market, and I have seen it disappoint people. Under ECO4 Flex, the funding pays the energy supplier's contribution towards approved measures. For a straightforward air source heat pump in a suitable home, that can mean no cost to you at all. The complications appear when your home needs supporting work.

What is commonly fully funded:

  • The air source heat pump unit and its installation.
  • Loft or cavity wall insulation where needed to make the home heat pump ready.
  • A heating controls upgrade.

What may need a top up from you:

  • Larger radiators or a complete radiator upgrade for low flow temperature operation.
  • A new hot water cylinder if your current one is unsuitable.
  • Solid wall insulation, which is expensive and not always fully covered.
  • Ground source heat pumps, which ECO4 rarely funds in full because they cost far more than air source.

Ground source is the usual sticking point. Because the scheme prioritises cost effectiveness, air source pumps win almost every time. If you specifically want ground source, expect to contribute. The reasons behind that choice are set out in our air source vs ground source comparison.

A realistic expectation for 2026 is this. A well insulated three bedroom home with decent radiators can often get a genuinely free air source install under Flex. A cold solid wall home with tiny microbore radiators might still face a few hundred to a couple of thousand pounds of top up work, because the pump will not perform without it.

Does Your Home Suit a Heat Pump?

Funding is wasted if the heat pump then runs badly and racks up bills. This is where my survey experience matters more than any grant paperwork. A heat pump works best at a low flow temperature, which means it heats water to around 45 to 50 degrees rather than the 70 plus a gas boiler uses. To deliver enough warmth at that lower temperature, the home needs three things.

  • Reasonable insulation. Loft insulation topped up to current standard and cavity walls filled where possible. ECO4 can fund this.
  • Adequately sized emitters. Radiators large enough to give off heat at low temperature, or underfloor heating.
  • A proper heat loss survey. Every credible install starts with a room by room heat loss calculation, not a rule of thumb.

Do not skip the heat loss survey, and do not accept an installer who sizes a pump from the floor area alone. An oversized pump short cycles and wears out. An undersized one leaves you cold in January. Our EPC and heat pump requirements guide explains how the rating interacts with funding, and you can gauge your starting point with the home suitability check.

The Insulation First Principle

If your council or installer suggests insulating before or alongside the heat pump, take the advice. It is not upselling. A pump in a leaky home will run at higher flow temperatures, lose efficiency and cost more to run. Getting the fabric right first is the difference between a heat pump that saves money and one that quietly disappoints.

How to Apply for ECO4 Flex Step by Step

There is no national online form for Flex. The process runs through your council and an installer working with an obligated supplier. Here is the sequence that works.

  1. Find your council's Statement of Intent. Search your local authority name plus ECO4 flexible eligibility. Read the income and vulnerability criteria.
  2. Check the household and property gateways. Confirm your income, EPC and any health criteria against the local rules and the gov.uk ECO4 overview.
  3. Submit a declaration. Some councils have an online declaration form, others route you through an approved installer who submits on your behalf.
  4. Book a survey. An installer carries out a heat loss survey and an EPC or retrofit assessment.
  5. Get the measures approved. The installer and supplier agree the funded measures. You are told in writing what is covered and what, if anything, you pay.
  6. Installation and sign off. Work is completed by a TrustMark registered business and, for the heat pump itself, an MCS certified installer.

Two quality marks protect you here. The installer should be TrustMark registered for ECO work, and the heat pump install should be carried out under MCS certification. If either is missing, walk away. Our guide on how to find an MCS certified installer covers the checks in detail.

What to Have Ready

Speed matters because the scheme is closing. Have proof of income, any benefit or health documentation, your EPC certificate number if you have one, and details of your current heating system to hand before you contact anyone. It shortens the assessment and reduces the chance of a delayed application.

Deadlines, Risks and Common Mistakes

ECO4, and therefore the Flex route within it, is scheduled to run until 31 March 2026. Suppliers front load delivery, so funded slots for heat pumps get scarce well before the final deadline. If Flex is your route, treat 2026 as the year to act rather than a comfortable window.

A few mistakes come up again and again in the homes I visit.

  • Assuming Flex is automatic. You must be nominated. If your council has not published or updated its Statement of Intent, chase it.
  • Chasing ground source under a scheme built for air source. You will usually be disappointed on funding.
  • Ignoring the fabric. Taking the pump but refusing the insulation leaves you with high bills and blaming the technology unfairly.
  • Using a non certified installer. Without MCS and TrustMark you lose consumer protection and, in some cases, the funding itself.
  • Confusing ECO4 with the Boiler Upgrade Scheme. They have different eligibility and different deadlines. Applying to the wrong one wastes time you may not have.

The scale of ECO delivery is set out in the government's ongoing household energy efficiency national statistics, which track how many measures have been installed under the obligation. It is a useful reality check. Demand is high, the pot is finite, and the households that prepare their paperwork early are the ones that get funded. If your income sits above the local cap, redirect your energy towards the Boiler Upgrade Scheme rather than waiting for a Flex nomination that will not come.

If your income is low but you are unsure whether cold at home is affecting your health, it is also worth checking wider support such as the Warm Home Discount scheme, which can run alongside efficiency work.

FAQ

Is ECO4 Flex a separate grant from ECO4?

No. ECO4 Flex, sometimes called LA Flex or Flexible Eligibility, is a qualification route inside the main ECO4 scheme. It lets your local council nominate you when you do not receive qualifying benefits. The funding, measures and rules are the same as standard ECO4.

What income can I earn and still qualify for ECO4 Flex?

There is no single national figure because each council sets its own limit in its Statement of Intent. A gross household income under roughly £31,000 is a common threshold, but some councils set it lower or adjust it for household size and vulnerability. Always check your own local authority's published criteria.

Will a heat pump be completely free under ECO4 Flex?

Often yes for a straightforward air source install in a suitable home. However, extra work such as larger radiators, a new hot water cylinder or solid wall insulation may require a top up. Ground source heat pumps are rarely funded in full because they cost far more than air source.

Do I apply for ECO4 Flex directly on gov.uk?

No. You apply through your local council or an ECO4 installer working with an obligated energy supplier. Start by reading your council's ECO4 flexible eligibility Statement of Intent, then submit a declaration and book a survey.

When does ECO4 Flex end?

ECO4, and the Flex route within it, is scheduled to run until 31 March 2026. Funded heat pump slots tend to run low before the deadline, so it is best to apply early in 2026 rather than leaving it late.

What if my income is too high for ECO4 Flex?

If you earn above your council's cap, the Boiler Upgrade Scheme is the realistic alternative. It offers a £7,500 grant towards an air source heat pump with no income test, and runs until 31 March 2028.

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