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How Much Is Cavity Wall Insulation?

cavity wall insulation cost

Are you unsatisfied with the amount of heat your home appears to be retaining? Or perhaps you are experiencing an unforeseen increase in your energy bills? If so, it might be time to consider purchasing cavity wall insulation.

Designed specifically to ensure that your home retains more heat, cavity wall insulation can reduce your energy bills, minimise your carbon footprint, and make your house more comfortable to live in. In this article, we will outline: what cavity wall insulation is, the different types of materials available, the pros and cons of cavity insulation, how much it may cost, how much you can save, and how long cavity wall insulation is predicted to last for.

What Is Cavity Wall Insulation?

Cavity wall insulation refers to a material that is placed in the gap (or the cavity) of the walls in your property. You may not know this, but there could be a gap between the internal and external walls of your home that may be making your property less energy efficient. Cavity wall insulation aims to minimise heat loss by trapping heat inside your home, and preventing air from circulating within the cavities of your property.

Types Of Cavity Wall Insulation

Now that you know what cavity wall insulation is, you may be wondering what types of materials are used to complete the installation. There are three main types of cavity wall insulation used in residential properties, which are: blown mineral fibre, polystyrene beads, and polyurethane foam.

Blown Mineral Fibre

One of the most popular forms of cavity wall insulation is blown mineral fibre, which typically uses either strands of fibreglass or mineral wool. Then, using compressed air, the material is forced into the cavities of your home. Finally, after being inserted, the fibre expands to fill the cavities. This insulation material is known for being cost effective and easy to install.

Polystyrene Beads

Similar to the previous method, polystyrene beads are also blown into the cavities of your walls using compressed air. Again, the expanding polystyrene beads will then fill the cavity in your walls. However, this method is more common when installing insulation in a more narrow wall cavity.

Polyurethane Foam

Polyurethane foam is injected into your cavity walls, with the foam forming instantly. This type of insulation material has been known to provide even results that do not require an extensive amount of maintenance once installed.

How Do I Know If My House Has Cavity Walls?

Residential properties throughout the United Kingdom will either feature solid walls or cavity walls. If your property features solid walls, you will not be able to have cavity wall insulation installed on your property.

But how will you know if you have cavity walls? Typically, homes that were built from the 1920s will feature cavity walls. Pre 1920s buildings typically feature solid walls. Additionally, you should take notice of your brick walls. If your brick walls are all laid lengthways in an even pattern, you more than likely have cavity walls.

If you are still unsure, then you can also hire an engineer to come out and determine whether you require cavity wall insulation. This is a service we provide at ZOA Eco Grants, so why not get in touch.

Pros And Cons Of Cavity Wall Insulation

Benefits Of Insulating Cavity Walls

Advantages of cavity wall insulation
Advantage Example
Reduce your energy bills The aim of cavity wall insulation is for it to help retain heat in your home. This should make you less reliant on your central heating system, which will lead to a reduction in your energy bills.
Minimise your carbon footprint By making your home more energy efficient, and reducing your reliance on your central heating system that may use fossil fuels to run it, you will be able to reduce your household’s carbon footprint.
More comfortable home Not only will cavity wall insulation make your home warmer in the winter months, but it will also help your property keep cooler in the summer months. Which will overall make your home a more comfortable place to live.
Quick installation time Depending on the size of your property, installing cavity wall insulation will more than likely take less than 24 hours to install. 


Drawbacks Of Insulating Cavity Walls

Disadvantages of cavity wall insulation
Disadvantage Example
High initial costs Like any other energy efficiency method, installing cavity wall insulation comes with a high initial cost. However, insulation can save you money in the long run.
Risk of cold spots Due to the hard to reach nature of the cavity in your walls, ensuring that there is even distribution of insulation is difficult to achieve. If part of your wall hasn’t been insulated properly, it can lead to the development of a cold spot, which could result in condensation or even mould.
Installation issues Installing cavity wall insulation is a difficult task, but if the job hasn’t been completed correctly, it could lead to a host of issues. The final consequence of these problems may cost you money either when fixing the issues or you may have to pay higher heating bills because you have received insufficient insulation.
Unsuitable properties Not all properties are suitable to have cavity wall insulation. If your home has solid walls or the cavity is too small, you will not be able to receive the benefits of the insulation method.


Cavity Wall Insulation Cost

Now that you know about the different types of cavity wall insulation as well as the pros and cons of adding cavity wall insulation, you may be wondering how much the investment will cost you. However, the cost of your cavity insulation will depend on a variety of different factors, including the:

  • Size Of Your Home: Of course the size of your property will have a huge influence on the cost of your cavity wall insulation installation. The bigger your property, the more wall cavities that will need to be filled, the more expensive the cavity wall insulation work will be.
  • Type Of Walls In Your Home: In order for your home to qualify for cavity wall insulation, you need the gap between your inner walls and exterior wall to measure at 50 mm. If your property’s cavity is too small, then you will not qualify for cavity wall insulation.
  • Insulation Material You Choose: The three main types of cavity wall insulation material cost various prices. We will outline the average cost of each material further below.


How Much Will It Cost To Install Cavity Wall Insulation In My Home?

As we have previously stated, there are many variable impacts that can influence your final cavity wall insulation cost. However, to give you a guideline on how much cavity wall insulation may cost you, the table below outlines the average cost of cavity wall insulation depending on the property type you live in:

How much does cavity wall insulation cost on average?
Property type Average cost of cavity wall insulation
Flat £950
Bungalow £2,400
Terrace house £1,800
Semi-detached house £2,700
Detached house £3,200

If you are yet to consider which cavity wall insulation materials you wish to install in your home, the table below will provide you with a general guideline as to how much each material may cost you on average:

How much does each cavity wall insulation material cost?
Insulation material Cost per m2
Polystyrene beads £18 to £22 per m2
Polyurethane foam £22 to £26 per m2
Mineral fibre £13 to £18 per m2

If you are looking for more specific figures relating to how much cavity wall insulation will cost your household, then why not get in touch with ZOA Eco Grants today? Our insulation experts can provide you with guidance as to how much cavity wall insulation may cost you.

Additional Cavity Wall Insulation Costs

While the previous figures have outlined how much the initial cost of the cavity wall insulation itself may cost you, there are additional costs that you will also need to take into account.

Removing Cavity Wall Insulation Previously Installed

If your household already has cavity wall insulation, but it needs replacing, this will come at an additional cost. Alternatively, there may be debris located in the wall cavity that needs removing before insulation installation can begin. Both of these issues could cost you around £50 to £100 depending on the nature of the job.

Booking The Initial Survey

As we have previously mentioned, if you cannot determine whether you have cavity walls, or if you are just looking for a second opinion, then you will want to book an initial survey. Typically, this will set you back £75 on average.

Pre-Installation Repairs

During either the survey or installation process, you may discover that your wall ties need replacing. Wall ties are present in properties with cavity walls as they are used to tie your internal and external walls together. If one or more of your wall ties have been damaged, you will need to have them replaced before your cavity wall insulation can be installed. This could set you back between £1,000 to £2,000 depending on the damage and size of your walls.

Roof Insulation

Typically when you are having cavity wall insulation installed, you may want to consider also opting for loft insulation. All engineers would recommend having your roof insulated as heat rises, meaning an uninsulated loft space can lead to an excessive amount of heat loss. If you are interested in purchasing roof insulation, or wondering about the cost of loft insulation, ZOA Eco Grants also provides this service and we can even help you access grants to make the whole thing cheaper.


Can I Get Free Cavity Wall Insulation?

In the UK, there are a variety of cavity wall insulation grants available to reduce insulation cost. Here at ZOA Eco Grants, we are committed to saving you as much money as possible on your cavity wall insulation. There are three main grants that you can apply for to save money on your insulation, which are:

  • ECO4 scheme.
  • LA Flex scheme.
  • Great British Insulation Scheme.

How Can The ECO4 Scheme Save You Money On Your Cavity Wall Insulation?

The ECO4 scheme was designed by the UK government to help low income families and the most vulnerable members of our community to improve their home’s energy efficiency levels. Not only will this help them save money on their energy bills, but also reduce their carbon footprint. To be eligible for this grant, you must:

  • Have at least one member of your household claim means-tested benefits.
  • Have an energy performance certificate (EPC) rating of D or lower.
  • Your household income must fall below a specific number.

LA Flex Scheme

The LA Flex scheme is a branch off of the ECO4 scheme, which aims to achieve the same objectives. However, the LA Flex initiative provides local authorities with additional powers to provide specific households with energy efficiency funding. This power is to be used in cases where a household does not fulfil the ECO4 scheme eligibility criteria, but there are extenuating circumstances which means they should be eligible.

How Can The Great British Insulation Scheme Help Save Me Money?

The final government grant you can apply for to get a reduction in the cost of your cavity wall insulation is the Great British Insulation Scheme. Similar to the ECO4 scheme, this initiative also targets household’s with low energy efficiency ratings as well as low income families. In order to meet the eligibility criteria for this scheme you must:

  • Have an EPC rating of D or lower, and live in a council tax band of either A to D in England, or A to E in Scotland and Wales.
  • OR one member of your household must receive means-tested benefits, and you must have an EPC rating of D or lower.


How Much Money Can I Save By Installing Cavity Wall Insulation?

Now that you know about cavity wall insulation cost, you may be wondering how much money the insulation can save you once installed. Similar to the cost of cavity wall insulation, how much it can save you also depends on a variety of factors, including:

  • The size of your house.
  • What type of cavity wall insulation you have installed.
  • If the insulation was correctly installed.

But to give you a general idea of the amount of savings that your household can make, the table below details the average amount of savings depending on the type of property you may live in:

How much money could I save by installing cavity wall insulation?
Property type Average saving on your energy bills
Terrace house £235 a year
Bungalow £310 a year
Semi-detached house £395 a year
Detached house £310 a year


How Long Does Cavity Wall Insulation Last For?

While the insulation installer and the type of insulation material you opt to have installed may influence the longevity of your insulation, correctly fitted and installed cavity wall insulation should last the entire lifespan of the property. In addition, you should also ensure that your insulation installer is certified by the Cavity Insulation Guarantee Agency (CIGA), as they should provide you with a 25 year guarantee as standard. The only issues that could negatively impact the lifespan of your wall cavity insulation is if it has been installed incorrectly, or if your home has had a dampness issue.


How Much Is Cavity Wall Insulation Summary

Have you decided to enhance your household’s energy efficiency rating by installing cavity wall insulation? We believe that the amount of money you will save on your heating bills, teamed with the long predicted lifespan of cavity wall insulation, makes installing insulation in your cavities a no-brainer.

Depending on what type of insulation you opt for, the measure will cost you between £13 and £26 per m2 on average. In the table below, we have outlined how much cavity wall insulation will cost you depending on the property type you have, as well as how much you can save, on average:

How much will cavity wall insulation cost me?
Property type On average how much cavity wall insulation will cost On average how much cavity wall insulation will save you
Terraced house £1,800 £235 a year
Bungalow £2,400 £310 a year
Semi-detached house £2,700 £395 a year
Detached house £3,200 £310 a year

Have you decided to take the plunge? Why not get in touch with ZOA Eco Grants, where one of our insulation experts can start you on your journey towards insulated cavity walls, today.

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