Take a moment to imagine your home on a frosty morning. You’ve cranked the heating up, yet the walls still feel cold to the touch. The culprit? Heat escaping through uninsulated or poorly insulated cavity walls. Although modern homes often have insulation built in, millions of older properties have a gap (or cavity) between their inner and outer walls that’s ripe for improvement. Cavity wall insulation fills that space with an insulating material—usually mineral wool or polystyrene beads—dramatically cutting heat loss.
The result? A cosier home that requires less energy to heat. Less energy means lower bills, and lower bills mean more money in your pocket each month. So if your property has cavity walls and you haven’t yet insulated them, you’re likely missing out on some serious savings. The question is: Could you get a grant to help cover the cost?
The answer might be yes. Read on to learn how government-backed programmes like ECO4 (Energy Company Obligation) and the Great British Insulation Scheme could help—and then scroll to the bottom of the page to use our Eligibility Checker. In just a few clicks, you’ll know if you qualify for funding.
How to Get a Grant for Cavity Wall Insulation in the UK
Two major schemes in the UK currently focus on helping households improve energy efficiency:
ECO4 (Energy Company Obligation)This programme requires energy suppliers to fund or partially fund energy-saving improvements in eligible homes. Cavity wall insulation is often at the top of the list for cost-effectiveness.
Great British Insulation Scheme (GBIS)While the scheme covers a range of insulation types (loft, internal, solid wall), it also supports cavity wall insulation for qualifying households. The goal is to raise overall home energy performance, reducing both bills and carbon emissions.
How do you tap into these opportunities?
Check Your Eligibility: Scroll to the bottom of this page and use our Eligibility Checker. You’ll answer a few questions about your property and circumstances, and we’ll let you know if you’re in line for a grant.
Book a Home Assessment: If you qualify, a certified assessor will inspect your walls, measure your cavities, and confirm your home is suitable.
Receive Your Grant Offer: You’ll learn how much of the cost is covered by the scheme—sometimes 100%, other times a partial subsidy.
Professional Installation: A vetted installer drills small holes in your exterior walls, injects insulation, and then seals the holes—usually all within a day or two.
How Much Money Could I Save by Insulating My Cavity Walls?
Let’s talk figures. According to various energy advisory sources, insulating your cavity walls can knock £150 to £400 off your annual heating bill—sometimes even more, depending on your home’s size and existing insulation levels. Over a decade, that could add up to thousands in savings.
Beyond the monetary benefits, you’ll likely notice a more consistent indoor temperature, fewer draughts, and less strain on your boiler or heating system. That means not only lower bills but also a smaller carbon footprint. It’s a win-win for your wallet and the environment.
Common Pitfalls When Installing Cavity Wall Insulation
Cavity wall insulation might sound straightforward—drill holes, inject insulation, fill holes—but there are risks if it’s not done properly:
Damp and Condensation: If the installer doesn’t assess your property’s exposure to driving rain or check for cracks in the external brickwork, you could end up with moisture issues down the line.
Inappropriate Materials: Different cavities require different types of insulation (e.g., mineral wool vs polystyrene beads). The wrong choice can reduce effectiveness or create damp spots.
Uncertified Installers: Hiring someone who isn’t familiar with ECO4 or GBIS guidelines can lead to subpar work—or even disqualification from grant funding.
At Energy Grant Service, we connect you with certified installers who adhere to official standards, ensuring your cavity walls are insulated safely, effectively, and in compliance with scheme requirements.
Cavity Wall Insulation as Part of a Whole-Home Retrofit
The Great British Insulation Scheme emphasises a holistic approach. Insulating your cavity walls is a great start, but why not explore other improvements at the same time? Consider pairing it with:
Loft Insulation to stop heat escaping through the roof.
Internal Wall Insulation for areas with solid walls or tricky corners.
Heating Controls or a New Boiler to optimise energy usage.
Solar Panels to offset electricity costs if you have an electric-based heating system.
By combining multiple measures, you can drastically boost your home’s Energy Performance Certificate rating, often jumping from a D or E band to a more efficient C—or even higher. That means deeper savings, improved comfort, and a smaller carbon footprint.
The Dangers of Going It Alone
Some homeowners decide to skip the grant process, hiring the cheapest contractor they can find. This can backfire:
Shoddy Workmanship: If the cavity isn’t filled evenly or the wrong materials are used, you could face cold spots, damp, or even structural issues.
Long Disruption: Inexperienced teams might take days—or weeks—to complete a job that should only take a day or two.
Lost Funding: If the work doesn’t comply with ECO4 or GBIS standards, you could lose out on any grant you might otherwise have qualified for.
By working with Energy Grant Service , you gain access to reputable, accredited installers who know the schemes inside and out, ensuring a smooth experience and maximum financial benefit.
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