Insulation Grants in 2026: ECO4 and What Changed

Your gas bill has just hit £1,847 for the year, and you've noticed the upstairs bedroom feels distinctly cooler than the rest of the house.

A neighbour mentioned they got their loft insulated for free through some government scheme, but when you search online, you're met with a maze of acronyms, conflicting eligibility criteria, and companies promising the world.

Is ECO4 still running in 2026?

Did you miss the boat?

And crucially—if you don't qualify for a grant, is insulation still worth paying for yourself?

What Exactly Is ECO4 in 2026?

The Energy Company Obligation (ECO) is a government-mandated scheme requiring large energy suppliers to fund energy efficiency improvements in British homes.

ECO4 is the fourth iteration, launched in April 2022 and originally scheduled to run until March 2026.

However, the scheme has been extended and modified, with the current phase now running through to March 2027, giving households additional time to apply.

Unlike previous iterations that allowed "able-to-pay" households to access subsidised insulation, ECO4 focuses almost exclusively on low-income and vulnerable households.

The scheme targets homes with poor energy efficiency—specifically those rated EPC D, E, F, or G—and aims to lift them up the energy performance scale.

The key difference in 2026 is the tightened targeting: suppliers must now demonstrate that at least 50% of their obligated measures go to households in the "core group" of means-tested benefit recipients.

Energy suppliers obligated under ECO4 include the "Big Six" plus several medium-sized suppliers: British Gas, EDF, E.ON, Octopus Energy, OVO Energy, Scottish Power, Shell Energy, Utilita, and others with over 150,000 domestic customers.

These suppliers pass the cost of the scheme onto all bill-payers through a small levy on energy bills—roughly £35-45 per year per household—so in a sense, you're already contributing to the pot whether you benefit or not.

Who Qualifies: The 2026 Eligibility Rules

Eligibility for ECO4 falls into two main categories: the "core group" and "flexible eligibility." Understanding which bracket you fall into determines not just whether you qualify, but how much funding is available and what measures you can access.

Core Group Eligibility

The core group consists of households where someone receives at least one of the following means-tested benefits:

A significant change in 2026 is how Universal Credit eligibility is assessed.

Previously, you qualified if you received UC at all.

Now, the Department for Work and Pensions shares earnings data with energy suppliers, and qualification depends on your assessed income period.

If your earnings fluctuate—common for self-employed people on UC—you may qualify in some months but not others.

The eligibility check uses your earnings from the assessment period ending in the month before your application.

Flexible Eligibility (ECO4 Flex)

Here's where things get interesting for households not on benefits.

Local authorities can nominate households for ECO4 Flex if they meet certain criteria related to low income and high energy costs, or vulnerability to the effects of living in a cold home.

In 2026, approximately 25% of ECO4 measures can be delivered through this flexible route.

Each local authority must publish a "Statement of Intent" outlining their specific criteria.

Most use a combination of income thresholds (typically household income below £31,000 after tax) and EPC ratings.

Some councils are more generous than others—Leeds City Council, for example, uses a £35,000 threshold for households with children, while more constrained councils stick rigidly to the £31,000 figure.

The referral process for ECO4 Flex differs from the core group.

You cannot apply directly through an energy supplier; instead, you must be referred by your local authority or an organisation they've authorised to make referrals.

This might be a Citizens Advice bureau, a housing association, or a charity like Age UK or Scope.

Some installers have partnerships with local authorities and can handle the referral paperwork, but always verify this independently.

What Insulation Measures Are Covered?

ECO4 takes a "whole-house" approach, meaning the measures installed must improve the property's EPC rating by at least one band where possible.

This differs from earlier schemes that allowed piecemeal installations.

The primary insulation measures available are:

Loft insulation: The most common measure and the easiest to install.

Current standards require 270mm of mineral wool insulation.

If your loft has 100mm or less, you qualify for a top-up.

If it's completely uninsulated, the grant covers the full installation.

Cost to the scheme: typically £300-800 depending on loft size and access.

Cavity wall insulation: For homes built between 1920 and 1990 with unfilled cavity walls.

The installer injects insulation material (usually blown mineral wool or polystyrene beads) into the cavity through drilled holes.

Cost to the scheme: £500-1,500 for a typical semi-detached house.

Note that cavity wall insulation has become more controversial due to damp issues in inappropriate properties—more on this later.

Solid wall insulation: For homes built before 1920 with solid walls (no cavity).

This can be external (insulation boards fixed to the outside, then rendered) or internal (insulation boards attached to interior walls).

External wall insulation transforms the appearance of a property and costs the scheme £8,000-15,000.

Internal wall insulation is cheaper at £5,000-10,000 but requires removing and refitting skirting boards, radiators, and sockets.

Underfloor insulation: Suspended timber floors can be insulated from below by attaching insulation between the joists.

This requires adequate crawl space (at least 600mm) and costs the scheme £1,000-3,000.

Solid concrete floors cannot be insulated retrospectively without major disruption.

Room-in-roof insulation: For converted lofts used as living space.

Insulation is fitted between rafters and over the existing plasterboard.

Particularly valuable for dormer bungalows and chalet-style houses.

Cost: £2,000-6,000.

The Great Cavity Wall Insulation Debate

Cavity wall insulation has been the subject of significant controversy, and for good reason.

When installed in appropriate properties, it reduces heat loss through walls by approximately 35% and saves the average household £150-250 per year on energy bills.

However, when installed in unsuitable properties, it can cause penetrating damp, mould, and structural damage that costs far more to rectify than the energy savings.

Properties unsuitable for cavity wall insulation include: those in areas with driving rain (exposed coastal locations, hillsides facing prevailing winds); walls already showing signs of damp; walls with structural problems or ties that have corroded; and cavities narrower than 50mm.

The British Board of Agrément (BBA) maintains a list of postcodes where cavity wall insulation is not recommended due to exposure to wind-driven rain.

"We had cavity wall insulation installed in 2019 through an earlier ECO scheme.

Within 18 months, we noticed damp patches on internal walls on the south-west facing side of the house.

A surveyor confirmed the insulation was holding moisture.

The removal cost £2,800, and we're still dealing with the internal redecoration.

The installer went into liquidation, so the guarantee was worthless." — Margaret Thornton, Plymouth, interviewed for this guide

The key protection is the Cavity Insulation Guarantee Agency (CIGA) guarantee, which runs for 25 years and covers rectification work if the insulation causes damp problems.

However, claiming on this guarantee can be a slow, frustrating process, and some installers have been known to cut corners on pre-installation surveys to maximise the number of installations.

What Changed from ECO3 to ECO4?

Understanding the changes helps explain why some people who qualified under ECO3 (which ended in March 2022) no longer qualify, and why the application process feels different now.

The most significant change is the move from "carbon reduction" as the primary metric to "bill savings" for low-income households.

Under ECO3, suppliers could meet their obligations by installing any measure that reduced carbon emissions, including relatively cheap measures like LED bulbs and smart heating controls.

ECO4 requires suppliers to focus on insulation and heating measures that deliver meaningful bill reductions—LEDs and smart controls no longer count.

Another change is the minimum installation standard.

Under ECO3, a supplier could install loft insulation in a home with an EPC rating of E and walk away.

Under ECO4, if that measure alone wouldn't lift the property to EPC D or better, the supplier must install additional measures.

This "minimum pathway" requirement means households often receive more comprehensive improvements, but it also means some properties are rejected as too expensive to bring up to standard.

The eligibility criteria have also narrowed.

ECO3 allowed anyone receiving any form of tax credit to qualify.

ECO4 introduced income thresholds for Working Tax Credit and Child Tax Credit recipients—£16,380 gross annual income.

This threshold