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.
The Cost of Cavity Wall Insulation
The cost of cavity wall insulation varies based on factors like property size, type, and the insulation material used. On average, prices can range significantly depending on where you live in the UK. Here is a visual representation of the potential costs associated with installing cavity wall insulation.
Here’s a breakdown of the typical costs depending on the type of property having its cavity walls insulated:
- Detached property – £4,300
- Semi-detached house – £2,700
- Mid-terrace house – £1,500
- Detached bungalow – £2,000
- Mid-floor flat – £1,100
Additionally, the cost may increase if existing insulation needs to be removed first.
If you need to remove failed cavity wall insulation, the process is straightforward but requires skilled labour and an industrial vacuum to safely extract the material.
We’ve created a user-friendly cavity wall insulation cost calculator in Google Sheets that allows you to input estimates and instantly calculate the cost of cavity wall insulation for your property.
DOWNLOAD FREE CAVITY WALL INSULATION COST CALCULATOR HERE
The Key Benefits of Insulating Your Home
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 expenses: 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.
Common Misconceptions About Cavity Wall Insulation
- Myth: “Cavity wall insulation causes damp.”
- Fact: Properly installed cavity wall insulation rarely causes damp. In fact, it can help prevent condensation by keeping walls warmer. However, it’s crucial to have a professional assessment to ensure your home is suitable.
- Myth: “It’s not worth it for older homes.”
- Fact: While homes built before 1920 may not have suitable cavities, many homes built between 1920 and 1990 can benefit significantly from cavity wall insulation.
- Myth: “The savings aren’t worth the investment.”
Fact: With potential annual savings of up to £680 on energy bills, most homeowners recoup their investment within 2-3 years.
Types of Cavity Wall Insulation
There are various forms, each offering unique benefits in terms of energy efficiency and cost-effectiveness. Choosing the right type for your home depends on factors like budget, insulation needs, and environmental impact. Here’s a brief overview of the most common types.
Most Popular Types of Cavity Wall Insulation in the UK
| Type of cavity wall insulation | What is it? | Pros | Cons |
| Expanding polystyrene granules or beads (EPS) | Beads or granules of polystyrene that are inserted into the cavity. | Eco-friendly and recyclable Damp resistant Easy to install Durable and lightweight Water resistant (prevents damp) | Not good at insulating sound You need to clean the cavity before installation Can cause gaps in your cavity |
| Polyurethane foam (PIR) | A type of spray foam that expands as it sets. | Incredibly efficient at insulating Easy to install Won’t cause mould Comes in a range of sizes and different types of materials | Not environmentally friendly and can’t be recycled More expensive than other options Material shrinks over time |
| Cavity wall boards | Insulation boards that are fitted whilst the house is being built. | An affordable option Fire resistant and usually water resistant Easy to install | Hard to retrofit, so more suited for new builds Less good at insulating than other options |
| Wool fibre | Insulation made from sheep wool. Usually comes in rolls, like a blanket, or as loose fibre. | Eco-friendly, renewable, and sustainable Fire resistant Soundproof Good at protecting from moisture / damp + mould development Resistant to rot | More expensive than other options Less thermal efficient than other options |
| Mineral fibre | Mineral fibres are molten rock that has been bound together and turned into sheets or loose fibres. | Can be blown into the cavity, which makes it easy to install Cheap to install Environmentally friendly | Cavity must be clean and spacious Prone to clumping, which can cause damp Repair is expensive |
In the UK, homeowners use a variety of materials for wall insulation to improve energy efficiency and reduce heat loss. The most common types of insulation used across the country include:
Mineral Fibre (Pink): The most widely used material, accounting for a significant portion of the insulation market due to its affordability and effectiveness in preventing heat loss.
Expanding Polystyrene Granules or Beads (EPS) (Blue): Popular for its lightweight properties and ease of installation, EPS is also commonly used.
Polyurethane Foam (PIR) (Yellow): Known for its high thermal performance, PIR foam is a preferred option for those looking for advanced insulation.
Cavity Wall Boards (Green): These boards provide excellent thermal resistance and are often used in properties that require stronger insulation.
Wool Fibre (Purple): Less commonly used, wool fibre offers one of the best natural and sustainable alternative for cavity wall insulation.
How to Check Your Home’s Suitability
Before you start looking at the cost for cavity wall insulation, it is important to check that your home is suitable.
Visual Inspection:
- Look for regular pattern of bricks (stretcher bond) on exterior walls
- Check wall thickness (typically over 260mm for cavity walls)
- Examine windows and door openings for visible gap between inner and outer walls
Professional Assessment:
- Borescope Inspection: A small camera inserted into a drill hole to visually inspect the cavity
- Thermal Imaging: Used to detect heat loss and identify areas where insulation might be missing or ineffective
- Cavity Width Measurement: Using specialised tools to ensure the cavity is wide enough (typically needs to be at least 50mm)
Pre-Installation Checks:
- Damp Assessment: Checking for any existing moisture issues that need addressing before insulation
- Wall Tie Inspection: Ensuring wall ties are in good condition to support insulation
- Ventilation Review: Assessing current ventilation to ensure it’s adequate post-insulation
Suitability Factors:
- Age of Property: Most homes built after 1920 are suitable, but those built before 1990 are most likely to benefit
- Location: Homes in exposed areas may require additional considerations
- Current Insulation: Checking if any existing insulation needs removal or can be topped up
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.
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: Ensure the installer is accredited by the Cavity Insulation Guarantee Agency (CIGA) or the British Board of Agreement (BBA), showing they are qualified to install insulation.
- Warranties: Choose an installer who offers a warranty, providing peace of mind that you’re covered in case any issues arise after the installation.
- Cost: The installation cost should be competitive. Get multiple quotes to compare, but remember that the cheapest option isn’t always the best for quality. Consider applying for a cavity wall insulation grant to reduce costs.
- Type of Insulation: Ensure the company can install the specific type of insulation you’ve chosen, as not all installers offer every type.
- Company Reputation: Look for recommendations from family and friends and read online reviews to gauge the reputation of the installer before making your choice.
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.
How to Pay for Insulation through the GBIS and ECO Scheme
If you’re struggling to cover the cost of insulation, there are government programs that may help, such as the Energy Company Obligation (ECO) Scheme and the Great British Insulation Scheme (GBIS). These schemes are designed to assist low-income or low-energy-efficiency households by reducing the heating bills and improving home energy efficiency.
ECO Scheme
- Under the ECO scheme, eligible households can receive cavity wall insulation grants.
- To qualify, you must be receiving certain benefits like Pension Credit, Jobseeker’s Allowance, or Employment and Support Allowance.
- Your property will also need to have an Energy Performance Certificate (EPC).
GBIS Scheme
- The GBIS aims to help households not currently benefiting from government ECO measures.
- Approximately 80% of the funding is allocated to households with lower energy efficiency, including those with an EPC rating of D or below or in the lower Council Tax bands.
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.
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.
Access Grants and Save on Energy Bills Today
As you can see, total cavity wall insulation costs depend on a number of factors. With the help available through the free funding schemes and the availability of grants, this is a great time to look at getting your property insulated effectively.
With the Free Insulation Scheme, homeowners can significantly reduce installation costs or even access wall cavity wall insulation grants completely free. These programs help lower your energy bills and improve your home’s efficiency, making it a smart investment.
Get your personalised cavity wall insulation quote today by clicking the button below and start saving!
FAQs
How much does wall insulation cost?
The average cost to install cavity wall insulation depends on the type of insulation and the size of your property. Cavity wall insulation prices generally range from £1,100 to in excess of £4,000. The overall house insulation cost can vary based on your home’s specific needs.
How to insulate cavity walls?
Insulating cavity walls involves injecting insulating material, such as foam or mineral wool, into the gap between the external and internal walls. This process helps to reduce heat loss and improves your home’s energy efficiency by addressing all your cavity wall insulation needs.
How do I know if I have cavity walls?
Homes built after the 1920s typically have cavity walls. You can check by looking at the brick pattern on your external walls. If the bricks are all laid lengthwise, your home may have cavity walls.
How long does it take to insulate cavity walls?
The process usually takes between 2 to 4 hours, depending on the size of the property. Larger homes with more walls to insulate may take longer.
How much does it cost to remove cavity wall insulation?
Cavity wall insulation removal can range from £1,000 to in excess of £2,500, depending on your home’s size and the type of insulation used. Removing cavity wall insulation that has failed is a simple and straightforward process if left in the right hands.
What insulation is best for cavity walls?
Mineral fibre insulation, urea formaldehyde foam and polyurethane foam are considered the best loft insulation for cavity walls. Each type has its own benefits, and the best option depends on the specific type of wall insulation and your property’s needs.
Can you get free cavity wall insulation?
Yes, under certain government schemes, households may be eligible to upgrade or have cavity wall insulation installed at little to no cost. It’s worth checking if you qualify for grants that can cover the cost, especially if you are on a low income or meet other eligibility criteria.
How much energy does cavity wall insulation save?
It can reduce heat loss by up to 35%, leading to significant savings on energy bills. On average, homeowners can save around £150 to £250 per year, depending on the costs and the efficiency of their heating system.
What are the building regulations for cavity walls?
Cavity wall insulation must comply with building regulations, ensuring that it meets thermal performance standards. The insulation should improve the U value of the walls, which measures how effective the insulation is at preventing heat loss.
What is the U value of cavity wall insulation?
The U value for cavity wall insulation typically ranges between 0.3 to 0.5 W/m²K, depending on the material used. A lower U value indicates better insulation, which reduces the cost over time by saving energy.
What should I do if I have problems after the installation?
If you experience issues after cavity wall insulation installation, such as damp patches on the walls, condensation on windows, or bubbling and flaking paintwork, these could be caused by poor ventilation, leaks, or faulty installation. The first step is to contact your installer, as they should assess and fix any problems, especially if the work is under warranty. It’s crucial to choose a qualified installer who provides a warranty or guarantee, ensuring that you have protection against any post-installation issues and that the problem can be resolved quickly.
