Internal Wall Insulation Grants: Improve Home Efficiency in 2025

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With energy prices remaining high across the UK, improving your home’s insulation is one of the smartest steps you can take to save money and stay warm. For many properties—especially older or solid wall homes—internal wall insulation is a practical and cost-effective solution. And thanks to government-backed insulation grants, you could get this upgrade for little or no cost.

This article explains everything you need to know about internal wall insulation grants, including eligibility, benefits, and how to apply under the ECO 4 scheme and other UK energy efficiency programs.

What Is Internal Wall Insulation?

Internal wall insulation (IWI) involves adding a layer of thermal insulation to the inside-facing side of external walls. This is especially useful for properties with solid walls, which allow heat to escape much faster than cavity walls.

The insulation boards or stud walls with mineral wool are typically covered with plasterboard and redecorated to blend in seamlessly with your home interior.

Why Consider Internal Wall Insulation?

Around 35% of UK homes have solid walls, particularly those built before the 1920s. These homes lose a significant amount of heat, making them expensive to heat and uncomfortable in winter.

Adding internal insulation to these walls can:

• Reduce heat loss by up to 45%

• Improve energy efficiency (EPC rating)

• Lower your carbon emissions

• Cut your heating bills significantly

• Make your home warmer and more comfortable year-round

And with internal wall insulation grants, this upgrade may be fully funded for eligible households.

What Are Internal Wall Insulation Grants?

Internal wall insulation grants are part of various UK energy efficiency grant schemes designed to help homeowners reduce energy bills and tackle fuel poverty.

Main grant programs include:

• ECO 4 Scheme (Energy Company Obligation)

• Great British Insulation Scheme (GBIS)

• LA Flex (Local Authority Flexibility)

• Home Upgrade Grant (HUG) – for off-gas grid properties

• Local Authority Delivery (LAD) scheme

These programs provide free or subsidised internal wall insulation to qualifying households, particularly those with solid wall properties and lower incomes.

Who Qualifies for Internal Wall Insulation Grants?

Eligibility criteria vary slightly by scheme, but the ECO 4 scheme has the most comprehensive coverage and is available until March 2026.

You may qualify if:

• You own your home or are a private tenant (with landlord consent)

• Your home has solid external walls

• Your property has an EPC rating of E, F, or G

• You or someone in your household receives a means-tested benefit, such as:

  • Universal Credit

  • Pension Credit

  • Income Support

  • Jobseeker’s Allowance (JSA)

  • Employment and Support Allowance (ESA)

  • Housing Benefit

  • Working or Child Tax Credits

Even if you don’t receive benefits, you may still qualify under LA Flex, which allows local councils to approve funding for low-income or vulnerable residents.

What Does the Grant Cover?

The grant can cover all aspects of internal wall insulation installation, including:

• Free energy performance survey (EPC)

• Thermal insulation boards or stud wall systems

• Plastering and redecorating work

• Damp and ventilation assessments

• Optional extra measures like loft insulation or draft-proofing

Installations must be carried out by TrustMark-registered and PAS 2035-compliant installers to ensure safety, quality, and energy efficiency standards.

Benefits of Internal Wall Insulation

🏠 Energy Bill Savings
Internal wall insulation can reduce annual heating bills by £250–£450 depending on your home size and existing heating system.

🌡️ Improved Comfort
Homes stay warmer in winter and cooler in summer with better-regulated internal temperatures.

💸 Increased Property Value
An improved EPC rating can increase your home's market value and make it more attractive to buyers and tenants.

🌍 Lower Carbon Footprint
Using less energy means you’ll produce fewer emissions, contributing to the UK’s Net Zero 2050 targets.

🧱 Discreet Appearance
Unlike external insulation, internal wall insulation doesn’t alter your home’s exterior, making it ideal for conservation areas or listed buildings.

What’s the Difference Between Internal and External Wall Insulation?

Both internal and external wall insulation help improve energy efficiency, but there are key differences:

If you're restricted from changing your home's exterior, internal insulation is the best option.

How to Apply for an Internal Wall Insulation Grant

The application process is typically managed by certified installers or energy efficiency providers.

Step-by-step process:

1. Check your eligibility on a government-backed website or through a registered installer.

2. Arrange a free home survey to assess your energy performance and insulation needs.

3. Your installer submits a grant application on your behalf.

4. If approved, you’ll be scheduled for installation—at no or minimal cost.

5. Work is completed by an accredited installer, and you begin saving!

Internal Wall Insulation Grant FAQs

❓ Is internal wall insulation disruptive?

Some disruption is expected, as installers will need to work inside your home. However, most projects can be completed room-by-room to minimise inconvenience.

❓ How long does it take to install?

It depends on your property size, but internal insulation can usually be installed within 5–10 working days.

❓ Do I need planning permission?

No—internal wall insulation doesn’t require planning permission, making it ideal for flats, terraced houses, and listed buildings.

❓ Will I have to pay anything?

If you meet the full criteria under ECO 4 or another grant scheme, the installation is often 100% free. In some cases, a small contribution may be required.

Other Energy Efficiency Measures You Can Combine

In many cases, grant-funded internal insulation is paired with other upgrades for maximum impact:

• Loft insulation

• Room-in-roof insulation

• Air source heat pumps

• First time central heating

• Smart thermostats and heating controls

Combining upgrades boosts your EPC rating and cuts bills even further.

Final Thoughts

The UK government’s commitment to improving housing efficiency makes now a great time to apply for internal wall insulation grants. Whether you're battling with high heating bills, living in a cold solid-wall home, or simply want to make your property more eco-friendly, grants under the ECO 4 scheme and other programs could help you insulate your home for free.

Don’t miss out on the chance to upgrade your home, lower your bills, and stay warm for less—check your eligibility today and take the first step toward a greener, warmer future.