Energy bills continue to be a significant concern for millions of UK households. With the average annual energy bill still well above pre-2022 levels, many homeowners are searching for practical ways to reduce their costs. The ECO 4 scheme, formally known as the Energy Company Obligation, is one of the most effective routes to achieving this, yet many eligible households have never heard of it.

This guide covers exactly what ECO 4 is, who qualifies, what improvements are available, and how to get started with your application.

What Is the ECO 4 Scheme?

ECO 4 is a government-backed energy efficiency programme that requires large energy suppliers to fund home improvements for eligible households across England, Scotland, and Wales. The scheme launched in April 2022 and runs until March 2026, with a total estimated value of around £4 billion.

The core aim is straightforward: improve the energy performance of the UK's least efficient homes, particularly those occupied by low-income or vulnerable households. Under ECO 4, qualifying properties can receive insulation, heating upgrades, and other measures at no cost to the homeowner.

Unlike previous iterations of the scheme (ECO 1, 2, and 3), ECO 4 focuses specifically on a "fabric first" approach. This means priority is given to insulation and draught-proofing before heating system replacements, as reducing heat loss delivers longer-lasting savings.

What Improvements Are Available Under ECO 4?

The range of measures funded through ECO 4 is broad. The specific improvements offered to your home will depend on its current Energy Performance Certificate (EPC) rating and which upgrades would deliver the greatest efficiency gains.

Insulation Measures

Loft insulation – topping up or installing loft insulation to the recommended 270mm depth
Cavity wall insulation – filling the gap between inner and outer walls to prevent heat loss
Solid wall insulation – internal or external insulation for older properties without cavity walls
Underfloor insulation – reducing heat loss through suspended timber or solid floors
Room-in-roof insulation – insulating converted loft spaces

Heating Upgrades

First-time central heating – for properties that have never had a full central heating system
Boiler replacement – upgrading broken or inefficient boilers (typically rated D or below)
Air source heat pumps – low-carbon heating alternatives for suitable properties
Heating controls – programmable thermostats and smart heating controls

Additional Measures

Draught-proofing around doors, windows, and letterboxes
Hot water tank insulation and pipe lagging
Ventilation improvements to address condensation issues

Who Qualifies for ECO 4?

Eligibility for ECO 4 is determined by a combination of property conditions and household circumstances. There are two main qualifying routes.

Route 1: Benefits-Based Eligibility

If you or anyone in your household receives one of the following benefits, you are likely eligible:

Universal Credit (with income thresholds)
Pension Credit (Guarantee Credit)
Income-based Jobseeker's Allowance (JSA)
Income-related Employment and Support Allowance (ESA)
Income Support
Child Tax Credit (with income below £16,480)
Working Tax Credit (with income below £16,480)
Housing Benefit

Route 2: Local Authority Flex (LA Flex)

Even if you do not receive qualifying benefits, your local council may refer you through the LA Flex pathway. This route is designed for households that are fuel-poor or vulnerable but fall outside the standard benefits criteria. Councils assess factors such as household income, health conditions, and property efficiency.

Property Requirements

Your property must also meet certain conditions:

An EPC rating of D, E, F, or G (the least efficient bands)
Located in England, Scotland, or Wales
Suitable for the proposed improvement measures

For a detailed breakdown of eligibility criteria, see our ECO 4 services page.

How Does the Application Process Work?

Applying for ECO 4 is simpler than many homeowners expect. Here is the typical process:

Initial eligibility check – confirm that your household and property meet the basic criteria
Property survey – a qualified assessor visits your home to evaluate its current energy performance and identify suitable measures
EPC assessment – if your property does not already have a valid EPC, one will be arranged
Measure recommendation – based on the survey, specific improvements are proposed
Installation – approved installers carry out the work, typically within a few weeks of approval
Post-installation inspection – quality checks ensure the work meets required standards

The entire process, from initial enquiry to completed installation, usually takes between four and eight weeks, depending on the measures involved and installer availability in your area.

How Much Can You Save with ECO 4?

The savings vary depending on your property type and the measures installed, but the figures are meaningful:

Cavity wall insulation can save approximately £295 per year on a typical semi-detached home
Loft insulation (from 0mm to 270mm) can save around £590 per year
Solid wall insulation can reduce annual bills by up to £640
A new efficient boiler replacing a G-rated model can save £400 or more annually

These figures are based on Energy Saving Trust estimates for a gas-heated semi-detached property. Actual savings depend on your home's size, construction, and energy usage patterns.

Common Questions About ECO 4

Is ECO 4 really free?

Yes. For qualifying households, the full cost of approved measures is covered by the energy supplier funding the scheme. You will not be asked to make a financial contribution.

Can private tenants apply?

Private tenants can benefit from ECO 4, but the landlord must give written consent for work to be carried out on the property. The landlord does not need to contribute financially.

Does it matter which energy supplier I use?

No. Your eligibility is not linked to your energy provider. The obligation falls on the largest suppliers, but any qualifying household can apply regardless of who supplies their gas or electricity.

Will ECO 4 affect my benefits?

No. Receiving ECO 4 improvements does not count as income and will not affect your benefit entitlements.

Take the First Step

If your home feels cold, your energy bills are too high, or your property has a low EPC rating, the ECO 4 scheme could make a genuine difference. At NAASS, we connect eligible homeowners with trusted ECO 4 installers and guide you through every step of the process.

Check your eligibility today and find out what improvements your home could receive at no cost.

What Is the ECO 4 Scheme? A Complete Guide for UK Homeowners