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How much is cavity wall insulation? This is a commonly asked question whenever people are considering ways to increase the heat and energy efficiency of their homes. Cavity wall insulation costs can range from a few hundred pounds for a small flat to several thousand for a large detached property but there are many benefits to insulating cavity walls that make it a worthwhile investment.

In this article, we will discuss how much cavity wall insulation costs, why you should consider it and how to get help with the costs through the insulation funding schemes.

Considering cavity wall insulation for your home? Enter your postcode here to see if you are entitled to receive 100% of the costs.

What is a Cavity Wall?

There are two main types of walls found in British homes; cavity walls and solid walls. A cavity wall is made up of two layers with a small gap or ‘cavity’ in between them. The inner leaf is usually brickwork and the outer leaf can be either brickwork or stone. Most homes built after the 1920s are likely to have cavity walls.

Why Does Your Home Need Insulating?

As houses age, the original insulation will start to degrade and become less effective. This is especially true for houses built before the 1990s when insulation standards were not as high as they are today.

There are many benefits of installing cavity wall insulation including:

  • Reducing your energy bills – Insulation works by trapping heat in your home, making it easier and cheaper to keep your house warm. With UK energy bills at an all-time high, insulating your cavity walls is a great way to reduce your costs.
  • Improving the comfort of your home – By trapping heat in your home, wall cavity insulation will help to even out the temperature, making it more comfortable to live in. As we head towards another cold winter, this is an increasingly important consideration.
  • Reducing your carbon footprint – By using less energy to heat your home, wall insulation will also help to reduce your carbon emissions. This is not only good for the environment but can also help to insulate you from future energy price rises.
  • Increasing the value of your property – Energy-efficient homes are becoming more and more popular, so insulating your home could make it more valuable if you ever decide to sell as the next inhabitants won’t have to do it themselves.

why does your home need cavity wall insulation

How to Check Your Home’s Suitability

Before you start looking at the cost of cavity wall insulation, it is important to check that your home is suitable. Not all homes are suitable for cavity wall insulation and if your property does not have cavity walls, you will need to look at alternative methods of insulation such as solid wall insulation or insulating external walls.

To check whether your home has cavity walls, you can:

  • Look at the outside of your property – If the outer layer of your wall is made up of small bricks or stones, then it is likely that you have cavity walls.
  • Check your home’s age – Most homes built after 1920 should have cavity walls but if you are unsure, you can check with your local authority or housing association.

If you are still unsure, you can contact a professional insulation company who will be able to advise you on the best way to insulate your home.

Considering cavity wall insulation for your home? Enter your postcode here to see if you are entitled to receive 100% of the costs.

Types of Cavity Wall Insulation

The cost of cavity wall insulation depends on the size and type of property you have. A small flat will inevitably cost considerably less to insulate than a large detached house. The type of insulation you choose will also affect the price. There are three main types of cavity wall insulation: Blown Mineral Fibre, Polystyrene beads or granules and Polyurethane Foam.

Blown Mineral Fibre is the most popular type of cavity wall insulation and is made from recycled glass or rock wool. It is blown into the cavity using a special machine and can be used on properties of any size.

Polystyrene beads or granules are also popular and are made from recycled plastic. They are poured into the cavity through small holes drilled in the outer wall. They are less effective than other types of insulation but are cheaper and can be used on properties with limited access.

Polyurethane Foam is a foam that expands to fill the cavity. It requires specialist equipment so should be left to expert cavity wall insulation installers rather than be attempted as a DIY installation. It is commonly used as an alternative to Urea Formaldehyde foam which has traditionally been used in cavities but typically fails over time.

How Much Does Cavity Wall Insulation Cost?

The cost of cavity wall insulation installation will depend on the size and type of property you have as well as the type of insulation you choose. As you can see from the chart above created by the Energy Savings Trust, a small mid floor flat will cost around £1000 to insulate while a detached house will cost around £4,600. However prices have been known to be as low as £410 for a mid floor flat and £2,500 for a detached area, depending on where you live in the UK. Deals can certainly be found, and if you enter your postcode with us today, we can help you find it. 

Costs of adding cavity wall insulation can also be impacted if you have existing installation that needs removing first. Removing cavity wall insulation that has failed is relatively straightforward in the right hands, but still requires skilled labour and an industrial vacuum to remove the cavity wall insulation material.

cavity wall insulation costs without a grant

How to Choose an Insulation Installer

When you have decided to insulate your home, the next step is to choose an insulation installer. There are a few things you should consider when making your choice:

  • Accreditations – The installer should be accredited by the Cavity Insulation Guarantee Agency (CIGA) or the British Board of Agreement (BBA). This shows that they are trained and qualified to install insulation.
  • Warranties – The installer should offer a warranty for their work. This will give you peace of mind that if there are any problems, you will be covered.
  • Cost – The cost of the installation should be competitive. However, it is important to remember that the cheapest option is not always the best as you want to make sure that the job is done properly. Get quotes from several installers before making your decision to ensure that you get the best possible price. You can save on cost with a cavity wall insulation grant.
  • The type of insulation – Not all installers will be able to install all types of insulation so make sure you choose a company that can install the type of insulation you have chosen.
  • The company’s reputation – Ask family and friends for recommendations and read online reviews to get an idea of what other people think of the company.

When you have chosen an installer, they will visit your property to assess it and give you a quote. Once you have accepted the quote, they will arrange a date to carry out the work. The installation process is usually quick and shouldn’t take more than a few hours.

Considering cavity wall insulation for your home? Enter your postcode here to see if you are entitled to receive 100% of the costs.

What if You Have Problems After Installation?

There are various common issues that you may unluckily encounter after your new insulation has been installed. These may include:

  • Damp patches appearing on the walls
  • Condensation on windows
  • Bubbling or flaking paintwork

These problems can be caused by a number of things such as poor ventilation, leaks or faulty installation. If you do encounter any problems, the first step is to contact your installer as they may be able to rectify the problem. This is why it is important to choose the right installer and make sure they offer a warranty or guarantee on the work. You will then be able to have the problem fixed without having to pay for it yourself.

Ventilation Considerations

Cavity wall insulation works by trapping heat in your home but if your property is not properly ventilated, this can lead to problems such as dampness and mould. It is important to make sure that you have adequate ventilation on your property before you have cavity wall insulation installed.

There are two main types of ventilation: natural and mechanical. Natural ventilation relies on air being able to circulate freely through your property. This can be achieved by opening windows and doors or by installing vents in the walls or ceilings. Mechanical ventilation uses fans to force air through your property. It is more expensive than natural ventilation but is sometimes necessary for properties with cavity wall insulation so check with your installer.

How to Pay for Insulation through the ECO Scheme

If you are struggling to afford the cost of insulation, you may be able to get help through the government’s Energy Company Obligation (ECO) Scheme or the Great British Insulation Scheme (GBIS). The schemes are designed to help low-income or low energy efficiency households reduce their energy bills and make their homes more energy-efficient.

Under the ECO scheme, eligible households can get free or discounted cavity wall insulation. To be eligible, you must be receiving certain benefits such as Pension Credit, Jobseeker’s Allowance or Employment and Support Allowance. You will also need to have an Energy Performance Certificate (EPC) for your property.

GBIS aims to help households not currently benefiting from government support for home ECO measures. Around 80% of the funding is earmarked for households considered some of the least energy-efficient in the country, including those with an EPC rating of D or below or in the lower Council Tax bands.

You can apply for free cavity wall insulation funding with the help of a Free insulation Scheme recommended installer. Once your application has been approved, the installer will arrange a date to carry out the cavity wall insulation work.

Considering cavity wall insulation for your home? Enter your postcode here to see if you are entitled to receive 100% of the costs.

What Else is Available through ECO?

As well as cavity wall insulation, the ECO scheme also offers other energy-saving measures such as loft insulation and solid wall insulation. You may be able to get these installed for free or at a discounted rate if you meet the eligibility criteria.

You can also get a free boiler or money towards a solar power or wind turbine system. Click here to find out more about what is available and who is eligible.

Tips for Keeping Your Home Warm

Once you have had your insulation installed, there are a few things you can do to keep your home warm and reduce your energy bills even further:

  • Install draught excluders around doors and windows – This will help to keep heat in and cold draughts out.
  • Get your boiler serviced regularly – This will ensure that it is running efficiently and isn’t wasting energy.
  • Seal any gaps in floorboards, skirting boards and around pipes – This will help to prevent heat from escaping.
  • Insulate your loft – Heat rises so it is important to make sure that your loft is well insulated.
  • Install double glazing – Double glazed windows are more energy-efficient than single glazed and will help to keep heat in.
  • Hang curtains over doors and windows – Curtains help to keep heat in and can also be used to block out sunlight in the summer.

Tips for Reducing Your Energy Bills

There are also a number of things you can do to reduce your energy bills. This is particularly important during the UK’s current cost of living crisis will average household energy bills set to hit £3,000 per year by October. Some simple money-saving tips include:

  • Turn off appliances when you’re not using them – This includes things like TVs, computers and lights which actually use a lot of energy when they’re left on standby.
  • Wash your clothes at a lower temperature – Most washing machines have a 30-degree setting which is just as effective as washing at a higher temperature but uses less energy.
  • Dry your clothes naturally – If the weather is good, dry your clothes outside on a washing line or clothes horse. Not only will this save you money, it’ll also make your clothes smell fresher.
  • Insulate your home – As we’ve already discussed, insulation is a great way to save money on your energy bills.
  • Switch to a cheaper energy tariff – There are a number of different energy tariffs available and switching to a cheaper one could save you a lot of money. You can do this easily by using an online comparison site.
tips for reducing your energy bills with cavity wall insulation

Considering cavity wall insulation for your home? Enter your postcode here to see if you are entitled to receive 100% of the costs.

installing cavity wall insulation

As you can see, the answer to “How much is cavity wall insulation” depends on a number of factors. However, there are many benefits to insulating your home, including reducing your heating bills and making your home more comfortable. With the help available through the free funding schemes and the availability of cavity wall insulation grants, this is a great time to look at getting your property insulated effectively. To find out what assistance you are eligible to receive, enter your postcode here.

In this Article

Oliver Creevy

Oliver Creevy

Ollie has been writing content in the home improvement sector for over 3 years and over the last 18 months has really specialised in Government grants, researching the different funding available to UK citizens. Ollie is well placed to provide households with access to the right advice when it comes to improving the energy efficiency of your home. With knowledge of the various grant schemes past and present, including Boiler Upgrade Scheme, ECO4, LAD Scheme, Green Homes Grant and more, his knowledge will be invaluable to those looking for ways to reduce their energy bills and reduce their carbon footprint through eco home improvement measures such as solar panels, insulation & heat pumps.

Free Funding to Install Home Insulation