Free cavity wall insulation: You could save energy and money.

Imagine standing next to an open window on a chilly, blustery day, feeling that unwelcome draft. Now, picture that heat loss happening across every external wall in your home.
That’s often what’s going on if you don’t have cavity wall insulation. Think of cavity wall insulation like a big, snug blanket, gently wrapping your walls to keep the warmth where it belongs, inside your home!
Recent reports from the Department for Energy Security & Net Zero (DESNZ) tell us that only 71% of properties in the United Kingdom currently have cavity wall insulation installed. That means millions of homes are missing out on a chance to reduce their carbon footprint, save energy, and maybe chip away at their energy bills.1 We’ve put together an easy guide to explain what cavity wall insulation is all about, and how you can take those simple, tangible next steps to make your home a little more sustainable, all while saving energy, time, and potentially money. Let’s explore!
What is cavity wall insulation?
If your home was built in the last 70 or 80 years, chances are your external walls are made of two "skins" – an inside and an outside wall – with a handy little gap, or cavity, in between them. Cavity wall insulation is simply about filling that gap with insulating materials like shredded mineral wool (a bit like fluffy glass fibre), polystyrene beads, or a special insulating foam.
It's good to know that, thanks to a building regulation change, homes built after 1982 should already have cavity wall insulation. But the really good news is, if yours doesn't, there are loads of grants and schemes available to help you get there.
Now, how does cavity wall insulation work its magic? We simply fill that gap. Imagine our friendly installers carefully drilling small, neat holes into the outside walls of your home. Through these holes, they gently inject the insulation material, such as mineral wool, beads, or foam, into the cavity. This material then fills the space, creating a cosy barrier that significantly slows down the rate at which heat can escape through your walls. It’s a bit like giving your home a wonderfully warm winter coat! The insulation doesn’t stop your heating from doing its job, it just helps it do it better, so you can stay comfortable using less energy.
The benefits of cavity wall insulation.
Reduced energy bills.
Insulating your walls helps keep more heat in, meaning you’ll need to use less energy to stay warm. Less heating usually means lower bills. Simple as that.
Warmer in winter.
Cavity wall insulation helps your home hold onto its heat, making it feel warmer and more comfortable during colder months.
Cooler in summer.
Insulation works both ways. In hot weather, it can help keep your home cooler by reducing heat from outside sneaking in.
Reduced carbon footprint.
By using less energy to heat your home, you’ll be cutting carbon emissions too. It’s one small change that can make a big difference over time.
Could boost your home’s value.
Energy efficiency improvements are often a selling point. A well-insulated home with a good EPC score may appeal more to buyers or renters.
Helps tackle damp.
Cavity wall insulation can actually help combat damp and condensation issues. By keeping your internal walls warmer, you reduce the likelihood of warm, moist air condensing on cold surfaces, which is often a cause of damp and mould.
Is my home suitable for cavity wall insulation?
While many homes can benefit, not every property is a perfect fit. Our experienced surveyors will always give your home a thorough check-up, but here's a little heads-up on what we generally look for:
Wall type.
Most homes built between the 1920s and 1980s are likely to have cavity walls and be suitable. If your home is older, say pre-1920s, it's more likely to have solid walls, which require a different type of insulation. Newer homes (post-1982) usually have insulation already built into the cavity.
Wall condition.
Cavity walls should be in good condition. If there are signs of structural issues, extensive cracks, or existing damp problems, we'll need to address those first. Our insulation needs a stable, dry environment to do its best work and last for years to come.
Accessibility.
Our team needs safe and clear access to all external walls of your home to properly install the insulation. This usually means ensuring there are no major obstructions like overgrown bushes, sheds, or conservatories that would prevent us from reaching every part of the cavity.
Height restrictions.
While we're pretty good with ladders and scaffolding, there can sometimes be height limitations, especially for very tall buildings or those with tricky access points. But don't worry, we'll assess all of this during our survey.
Cavity wall insulation grants and funding.
We understand that investing in home improvements can feel like a big outlay, but there are some fantastic grants and funding options out there that could significantly reduce, or even cover, the cost of your cavity wall insulation.
The Great British Insulation Scheme (GBIS).
The Great British Insulation Scheme (GBIS) is designed to help a wide range of households improve their home's energy efficiency. If you meet certain eligibility criteria, which often relate to your household income or if you receive certain benefits, you could be eligible for a grant that covers a significant portion, or even the full cost, of your cavity wall insulation. It's all about making warmer, more affordable homes a reality for more people.
We're dedicated to making this process as smooth and straightforward as possible for you. Our team of experts can help you understand the various grants available, check your eligibility, and even guide you through the application process. We're here to help you unlock those potential savings!
Ready to find out if you could get help with the cost? It only takes a few moments to check your eligibility for grants. Why not take the first step today and see what support might be waiting for you?
Check your eligibility.The cavity wall installation process.
If your home’s a good fit and funding is sorted, here’s what to expect during the installation.
Survey.
We’ll start with a proper assessment of your home to make sure insulation is right for your walls, identify any potential issues, and confirm the best approach for your property.
Drilling holes.
Small 22-25mm holes are drilled in the outer wall so we can access the cavity. These holes are usually drilled into the mortar joints, not the bricks themselves, to keep everything tidy.
Injecting insulation.
Using specialised equipment, our installers will then inject the chosen insulation material (whether it’s mineral wool, beads, or foam) into the cavity through these holes.
Sealing holes.
Once all the insulation is in place, our team will carefully seal all the drilled holes with mortar that's colour-matched as closely as possible to your existing mortar.
Clean-up.
We pride ourselves on leaving your home as tidy as we found it. Our team will clear away any debris and ensure the area around your home is clean and neat before they leave.
Guarantee.
All our cavity wall insulation installations come with a comprehensive guarantee. We're proud to be Qualitymark accredited, meaning your insulation is covered by a 25-year guarantee.
Cavity wall insulation and air source heat pumps.
Insulation and heat pumps are a bit like tea and biscuits, they work better together. Air source heat pumps are fantastic at providing efficient heating, but they work best in a home that's already doing a great job of holding onto its heat. If your home is losing warmth through uninsulated walls, your heat pump will have to work harder to maintain a comfortable temperature, potentially using more electricity.
By adding cavity wall insulation, you're essentially plugging those heat-loss gaps. This means your air source heat pump can operate more efficiently, using less energy to keep your home toasty. It's a bit like giving your heat pump a power boost! The combination can lead to even greater energy savings and a significant reduction in your overall carbon footprint. It’s all about creating a harmonious, energy-efficient living space.
Why choose E.ON Next for cavity wall insulation?
We’ve helped thousands of households already get the most out of their homes with energy efficiency upgrades, and cavity wall insulation is just one part of the picture.
We're here for you. We pride ourselves on being approachable, trustworthy, and knowledgeable. We’re not just an energy company; we're a team of passionate individuals dedicated to helping you make smart choices for your home and the planet.
Expertise you can trust. Our installers are highly trained, Trust-mark registered accredited professionals who know cavity wall insulation inside and out. They use the latest techniques and high-quality materials to ensure your installation is done right, the first time. We’re Qualitymark accredited, giving you that extra layer of confidence.
Unlocking grants. We’re here to help you navigate the world of grants and funding. Our team can guide you through the process, helping you understand what support might be available and how to access it. We want to make insulation as affordable as possible for you.
A seamless journey. From your initial enquiry to the final clean-up, we aim for a smooth, hassle-free experience. We’ll keep you informed every step of the way, so you always know what’s happening.
Choosing us means choosing a partner who genuinely cares about helping you save energy, save money, and create a more comfortable home. Let's make your home a cosier place, together!
Check your eligibility.Cavity wall FAQs.
How long does cavity wall installation take?
What type of insulation material is used?
Will there be any disruption to my home?
How much does cavity wall insulation cost?
Does cavity wall insulation cause dampness?
How long does cavity wall insulation last?
How do I check if I already have cavity wall insulation?
Can I mount a TV on a cavity wall?
Ready to find out more?
Let’s see if cavity wall insulation’s the right fit for your home. It’s quick to check, and we’ll help you every step of the way.