A guide to cavity wall insulation


In this series of retrofit measures blogs, we’ll be explaining different retrofit measures which can improve the energy efficiency of homes – reducing energy usage to cut energy bills and carbon emissions, and improve the comfort of your home.

We’ll include information on how the measure works, what types of homes it may be right for, what installation looks like, and more. In this post we’re looking at cavity wall insulation.

What is cavity wall insulation?

In uninsulated homes, around a third of heat loss is through the walls. This is particularly an issue in homes with cavity walls – which are made up of two walls (the outer usually brick; the inner usually brick or concrete) with a gap between them. Cavity wall insulation reduces this heat loss by filling the gap between the two walls – the ‘cavity’ with insulating material which prevents or reduces the leakage of heat.

How does cavity wall insulation work?

The most common method for fitting cavity wall insulation is for insulation material to be injected into the cavity – usually mineral wool, polystyrene beads, or polyurethane foam. This is done by drilling small holes in the outside walls at various intervals, injecting the material through the holes, and then filling the holes back up so they are not noticeable.

This procedure must be done by a professional and reputable installer to ensure it does not cause issues. If you work with Cosy Homes Oxfordshire on your home retrofit you’ll have access to our network of trusted contractors, who we will contact and manage for you.

What types of home does cavity wall insulation suit?

Cavity wall insulation is only relevant for homes which have cavity walls. If your home was built after the 1920s it will likely have cavity walls. If your home was built before 1920 it will probably have solid walls, and so solid wall insulation is more relevant for you.

Some homes with cavity walls will already have them insulated – it was common practice from the 1990s onwards to add insulation into cavity walls during construction.

Cavity wall insulation is not suitable for flats, unless you have agreement from the owners of all flats in your block to insulate the whole block.

If you aren’t sure what type of walls your home has, Cosy Homes Oxfordshire can help with that through our home assessment and Whole House Plan service.

What are the expected costs and savings?

As with any retrofit measure, the potential carbon and cost savings vary depending on the type and size of your home. Cavity wall insulation is a relatively simple measure which makes a big difference, and can reduce heat loss by up to a third – so it’s likely you can make substantial savings within 5 years of the insulation being installed.

The Energy Savings Trust predicts costs and savings as below (April 2019 data). Please note that you might be able to reduce these costs by carrying out the work at the same time as other home retrofit improvements through our Whole House Plan approach.

Detached houseSemi-detached houseMid terraceBungalowFlat
Typical cost (£)£610 £475£390£460£345
Energy bill savings (£/year)£280£165 £105£110 £85
Carbon emissions diverted (kgCO2/year)1150kg680kg 430kg460kg 335kg
GPT Rewrite

Title 1: Unleash the Power of Cavity Wall Insulation: A Cozy Solution to Save Energy and Money!

Title 2: Keep the Cold Out and the Savings In: Cavity Wall Insulation to the Rescue!

Say Hello to Lower Energy Bills with Cavity Wall Insulation

Did you know that your walls could be costing you money? In homes without insulation, a whopping one-third of heat loss happens through the walls. That’s like throwing your hard-earned cash out the window! But fear not, because we have a fantastic solution: cavity wall insulation. It’s time to take control of your energy efficiency and enjoy a cozier home while saving some pennies along the way.

So, how does cavity wall insulation work its magic? Picture this: a team of experts injecting insulation material into the cavity between your walls. They use high-tech methods like mineral wool, polystyrene beads, or polyurethane foam to fill every nook and cranny. It’s like giving your walls a warm, cozy hug. The best part? Once the job is done, those tiny holes they drilled in the exterior walls are barely noticeable. Your home will look as good as new!

Now, we know you might have some concerns about the process. That’s why we partner with only the most professional and reputable installers at Cosy Homes Oxfordshire. Our network of trusted contractors will ensure a seamless and hassle-free experience, leaving you with peace of mind.

But is cavity wall insulation right for your home? If your house was built after the 1920s, chances are you have cavity walls that are just begging to be insulated. However, if your humble abode predates the 1920s, solid wall insulation might be a better fit. Don’t worry if you’re unsure about your walls; our home assessment and Whole House Plan service can help you figure it out.

Let’s talk about the best part: the savings! Cavity wall insulation is like a superhero cape for your home, protecting it from energy waste and sky-high bills. By reducing heat loss by up to a third, you can expect substantial savings within just five years of installation. Imagine what you could do with that extra cash—treat yourself to a well-deserved vacation or indulge in your favorite hobbies!

To give you an idea of the potential costs and savings, here are some figures from the Energy Savings Trust (data from April 2019):

Detached house: Typical cost of £610, energy bill savings of £280 per year, and a carbon emissions reduction of 1150kg per year.
Semi-detached house: Typical cost of £475, energy bill savings of £165 per year, and a carbon emissions reduction of 680kg per year.
Mid terrace: Typical cost of £390, energy bill savings of £105 per year, and a carbon emissions reduction of 430kg per year.
Bungalow: Typical cost of £460, energy bill savings of £110 per year, and a carbon emissions reduction of 460kg per year.
Flat: Typical cost of £345, energy bill savings of £85 per year, and a carbon emissions reduction of 335kg per year.
Please note that these figures are just estimates and can vary depending on the size and type of your home. But don’t worry, we’re here to guide you through the process and find the best solution tailored to your needs.

Ready to say goodbye to chilly drafts and hello to cozy savings? Reach out to Cosy Homes Oxfordshire today and let us transform your home into an energy-saving haven. Don’t let your walls be the reason for your high energy bills—insulate and start enjoying the comfort and savings you deserve!