Cavity Wall Insulation: Is it worth the investment?

Unlock up to £160 per year in extra savings

Did you know that you could be as warm as toast and save up to £160 per year in heating bills just by insulating your walls?

If you are looking to reduce your heating bills then having your cavity walls insulated is one of the easiest, most cost-effective ways to do this. It will improve your home’s energy efficiency, meaning you stay warmer, and you save money. At Utility Saving Expert, we make it easy to find out how to insulate your cavity walls. To find out more complete the form on this page.

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What is cavity wall insulation and how does it work?

Cavity wall insulation is where an insulating material is pumped into the outer walls of a property for the purpose of stopping the heat escaping, but this can only be done if your property has cavity walls.

Originally, the purpose of the gap in your cavity walls was to help prevent rainwater from penetrating through the outer wall to the inside, which would make the internal walls of a property damp.

However, if the cavity is empty then it will retain the temperature of the outside winter air, and as heat is attracted to cold, the warmth from inside the property will escape through the bricks to the colder air outside, as nothing is keeping the warmth inside.

Also, when the heat from inside hits the cold internal walls, it creates condensation on the walls, making the room feel damp and creating mould on the cold walls.

Unfilled cavity walls could be responsible for around 35%, approximately one-third, of all heat lost from your home, meaning that you are spending more in energy to keep your home warm.

The colder it is outside, the faster the warmth home will escape. In a situation like this, you might turn up the heating thermostat to be warmer, only to find that more heat escapes through the uninsulated walls, which raises your energy usage and adds to your fuel bills.

Can I get cavity wall insulation?

Most houses in the UK have either solid walls or cavity walls, but it depends on when the house was built. For instance, if your house was built after the 1920s, you are most likely to have cavity walls. But, if your house was built in the past ten years, it’s likely that the cavity walls have already been insulated.

Older houses, build before the 1920s, are more likely to have stone walls without a cavity and are therefore not suitable for cavity wall insulation. However, there are alternative to insulating your home than filling the cavity.

Do you know if your home has a cavity wall or a solid wall? There is a way to tell. A cavity wall is made up of two walls with a cavity in between, usually at least 50mm wide. The outer wall will usually be made of brick and the inner layer of brick or concrete block.

You can tell if a cavity exists in your walls by measuring the width of the wall via a window or door on one of your external walls. If a wall is more than 260mm thick, then it probably has a cavity but if it is narrower than 260mm it probably doesn’t have a cavity. Stone walls may be thicker than the 260mm but are usually solid. A registered installer will be able to tell you if your property is suitable for cavity wall insulation.

Whatever the type of wall you have, you should be able to insulate it in some form, but you would need to seek specialist advice on how to do this. For further advice or to find an installer who can help you, contact the National Insulation Association.

To find out if you have cavity walls, or indeed if you already have insulation, you can ask a registered installer for a boroscope inspection, whereby a small hole is drilled in your external wall to see if your walls are hollow or filled.

How is cavity wall insulation installed?

Unfortunately, filling cavity walls is not a job for a DIY enthusiast. You will need to find a registered installer to do the job for you.

To insulate your cavity walls, the installer will drill small holes at 1-metre intervals into the outside wall of your home. The installer then blows insulating material into the cavity, usually mineral wool, polystyrene beads or foam, using special equipment.

It is important that the installer has access to all your external walls. Once all the insulation is in, the installer fills the holes in the brickwork.

The job should take no longer than around two hours for an average house with easily accessible walls.

What are the costs and savings?

According to the Energy Saving Trust, cavity insulation typically costs around £500 to install but you could save up to £155 per year in heating bills just by insulating the walls of a 3-bedroom, semi-detached property, or up to £275 for a detached property.

You’ll also be reducing your carbon emissions, so you’ll be doing your bit for the planet too. Estimates by the Energy Saving Trust show a reduction by approximately 660 KG of CO2 per year, for a three-bedroomed semi-detached house.

In previous years, many people benefitted from government-backed schemes which offered free or discounted cavity wall insulation. Though most of these offers have now ended, some cavity wall insulating companies still have access to Government funding and so can offer free or subsidised cavity wall insulation to some householders.

At Utility Saving Expert, we make it easy to find out how to insulate your cavity walls and save money on your energy bills. To get more information or to see if you qualify for help with your cavity wall insulation then complete the form on this page.