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What Are The Benefits Of Cavity Wall Insulation

concept image of cavity wall insulation

The Benefits of Cavity Wall Insulation

Are you tired of high energy bills and a home that’s never quite comfortable? The benefits of cavity wall insulation might be the answer to your problems.

In this blog post, we’ll explore the science behind cavity wall insulation, its benefits, material options, installation process, and the financial aspects, providing you with a comprehensive guide that will help you make an informed decision.


Short Summary


Cavity wall insulation is an effective way to improve the energy efficiency of a home and reduce heat loss.

It comes in various materials, each with its own unique characteristics and advantages.

Government grants and incentives are available to cover installation costs, potentially improving energy efficiency by up to 20%.

Understanding Cavity Wall Insulation

A diagram of a cavity wall showing the two walls and the insulation between themCavity wall insulation is a major energy saver for homeowners, as it prevents heat loss through conduction and convection by trapping warm air within the insulation material, effectively turning your home into a cosy fortress against the elements.

But how does this process work, and what types of cavity walls are suitable for insulation? Let’s find out.


Conduction and Convection

Conduction and convection are the two primary ways heat is lost through your home’s walls.

Conduction refers to the transfer of heat through a solid material, while convection is the transfer of heat through a liquid or gas.

Cavity wall insulation works its magic by filling the gap between the inner and outer walls of a building with an insulating material, reducing the amount of heat that can be transferred through both conduction and convection, ultimately making your home more energy efficient.

Now, how can you tell if your home has cavity walls?

The brickwork pattern is a significant clue. If you spot an even pattern with only the long edge of bricks exposed, you’re likely dealing with cavity walls, which are usually over 260mm thick.

Meanwhile, solid walls often have a mix of long and short brick ends and typically measure narrower than cavity walls.


Types of Cavity Walls

Cavity walls are a prevalent construction type in modern masonry homes, consisting of an inner blockwork wall, a cavity, and an outer wall of brick or rendered blockwork.

Most homes built after 1935 will have cavity walls.

To determine if a house is suitable for standard cavity wall insulation, the property should have cavity walls with a gap of at least 50mm and no narrow or uneven cavities and should not be located in an exposed site or have a risk of flooding.

There are several types of cavity wall insulation available, with the most suitable option depending on your budget and building type.


Advantages of Cavity Wall Insulation

Cavity wall insulation is a win-win solution for homeowners. It provides an array of benefits, such as improved energy efficiency, reduced environmental impact, and enhanced home comfort.

It siginificantly improves the energy rating on an Energy Performance Certificate (EPC). This makes it easier to reach a C energy rating required by The Minimum Energy Efficiency Standard and more and more mortgage lenders.

In the following sections, we’ll delve deeper into these advantages and how they can make a significant difference in the energy efficiency of your home.


Energy Efficiency

Energy efficiency is all about using less energy to achieve the same outcome.

By improving your home’s insulation, you’re effectively reducing the amount of heat lost through the walls and, subsequently, the energy required to maintain a comfortable indoor temperature.

Cavity wall insulation offers substantial energy efficiency benefits. It is estimated that around 35% of the heat lost in an uninsulated home escapes through the walls.

By insulating cavity walls, you can dramatically cut energy costs and save money on your heating bills, while also contributing to a greener environment.


Environmental Impact

Our homes have a significant impact on the environment due to their intensive energy and resource consumption during construction and operation.

This also contributes to greenhouse gas emissions, air, water, and noise pollution, and waste production. Cavity wall insulation can help mitigate these negative effects by decreasing energy consumption and CO2 emissions.

The environmental impact of the materials used for cavity wall insulation varies.

Mineral wool, a natural material, has a low environmental impact, whereas polystyrene beads and polyurethane foam, being synthetic, have a higher environmental impact.

Furthermore, the installation process itself can have detrimental environmental effects due to energy and resource consumption, as well as the potential for air, water, and noise pollution.


Increased Home Comfort

Home comfort is all about maintaining a pleasant temperature indoors, regardless of external weather conditions, and cavity wall insulation plays a crucial role in achieving this goal.

By reducing heat loss through the walls, it helps keep your home warm in winter and cool in summer, lessening the impact of weather variation on your indoor environment.

Moreover, cavity wall insulation can help reduce drafts and external noise, making your home a more comfortable and peaceful space to live in.

It can also contribute to lower energy bills by reducing the energy required for heating and cooling your home.

Lastly, cavity wall insulation can help decrease condensation and dampness in your home, minimising the risk of mold and mildew growth.

Material Options for Cavity Wall Insulation

man installing cavity wall insulationWhen it comes to cavity wall insulation, you have several material options to choose from, each with its unique properties and benefits. Popular materials include mineral wool, polystyrene beads, and polyurethane foam.

Let’s take a closer look at each of these materials and what they have to offer.


Mineral Wool

Mineral wool is a non-metallic inorganic material made from a combination of materials such as stone and glass. It is widely used for insulation in external walls, basements, and loft spaces.

Mineral fibre cavity wall is treated with a waterproof repelant which makes it suitable for the application of cavity wall insulation in both existing and new buildings.

Mineral wool insulation offers excellent insulation properties and is fire-resistant, making it a safe and effective choice for cavity wall insulation.

However, it thermal value, although good, may not be as high as other materials.


Polystyrene Beads

Polystyrene bead insulation is a type of insulation material consisting of small beads of polystyrene.

These beads are bonded together with an adhesive during the installation process, providing superior insulation while not retaining moisture.

Installation of polystyrene beads insulation is relatively quick and can be done using a long nozzle to inject the insulation into hard-to-reach areas.

However, it may be more expensive than other materials, and very often can be the only system that can be used if the property has difficult access issues, such as conservatories, areas where a ladders can’t be used or plant life that makes access to the wall difficult.


Polyurethane Foam

Polyurethane foam is an insulation material that is injected into a cavity wall, forming a water-resistant insulation barrier with excellent thermal performance.

It is highly effective at retaining heat, water-resistant, and straightforward to install.

On the downside, some polyurethane foams may not be as durable in the long term.

Nevertheless, polyurethane foam insulation is a versatile and efficient material option for cavity wall insulation, offering homeowners a high-performance solution for maintaining a comfortable and energy-efficient home.

Installation Process and Considerations

cavity wall insulation surveyor

To ensure the success of your cavity wall insulation project, it’s essential to identify the wall type, seek professional assessment and installation, and consider maintenance and ventilation.

In this section, we’ll explore these crucial aspects in more detail.


Identifying Wall Type

Determining your home’s wall type is crucial for successful insulation installation.

As we mentioned earlier, the brickwork pattern can help you identify if your home has cavity walls, with an even pattern indicating cavity walls and an alternating pattern suggesting solid walls.

If you’re unsure about your wall type or if your home has steel-frame, timber-frame, or pre-fabricated concrete construction, it’s best to consult a specialist insulation installer for guidance.


Professional Assessment and Installation

Filling cavity walls is not a DIY job; it requires the expertise of a registered installer. Professional bodies such as the National Insulation Association (NIA), the Cavity Insulation Guarantee Agency (CIGA), and the British Board of Agrément oversee cavity wall insulation and ensure that installers adhere to professional practice standards.

A qualified professional can complete the installation of cavity wall insulation in approximately two hours for a standard home with easily accessible walls. The installation comes with a 25-year guarantee from the CIGA, giving you peace of mind and assurance of quality work.


Maintenance and Ventilation

Proper maintenance and ventilation are vital for the long-term success of cavity wall insulation. Regular home maintenance checks should include looking for wall cracks, defective window seals, leaking gutters, and ensuring vents are not obstructed. If you experience issues with your cavity wall insulation, contacting the company that carried out the installation is recommended.

In addition to maintenance, adequate ventilation is essential for maintaining a fresh, dry, and healthy environment in your home. Building regulations require the provision of sufficient ventilation when installing wall insulation, which may involve installing additional vents if the existing number is inadequate.

Financial Aspects of Cavity Wall Insulation

saving energy with cavity wall insulation

Cavity wall insulation is an investment that pays off in the long run.

While there are initial costs involved, the long-term savings on energy bills and potential government grants and incentives make it a wise choice for homeowners.

Let’s explore the financial aspects of cavity wall insulation further.


Initial Costs

The initial costs of cavity wall insulation may vary from a few hundred pounds for a smaller flat to several thousand pounds for a larger detached property, with the typical cost for a semi-detached house being approximately £610.

The price range for different insulation materials, such as blown mineral wool, can also vary, with some options being more affordable than others.

While the initial costs may seem daunting, it’s essential to consider the long-term benefits and savings that cavity wall insulation can provide.


Long-term Savings

Cavity wall insulation can provide homeowners with annual savings of between £165 and £300 on their heating bills, depending on the size of their home and other factors. The initial cost of installation can generally be recovered within five years through energy bill savings.

In addition to the financial savings, cavity wall insulation also contributes to a more environmentally friendly home by reducing energy consumption and greenhouse gas emissions, making it a responsible choice for both your wallet and the planet.



Government Grants and Incentives

government grants for insulation

Homeowners and private renters may be eligible for government grants and incentives for cavity wall insulation, with funding amounts varying depending on their existing energy efficiency rating, tenure, and fuel type.

These grants can cover the full costs of installation and may improve the energy efficiency of a property by up to 20%.

The Energy Company Obligation (ECO) is one of the main government initiatives that provides funding for cavity wall insulation.

Individuals receiving specific means-tested benefits may also be entitled to 100% funding for insulation grants.


In conclusion, cavity wall insulation is a smart investment for homeowners looking to improve their home’s energy efficiency, reduce environmental impact, and enhance overall comfort.

By understanding the science behind cavity wall insulation, exploring material options, and considering professional assessment and installation, you can make an informed decision that will benefit your home and wallet for years to come.

Don’t let those high energy bills and uncomfortable living conditions get the best of you – consider cavity wall insulation today and enjoy a cosier, more efficient home.

Frequently Asked Questions


What is the downside to cavity wall insulation?

The downside to cavity wall insulation is that if it is not installed properly, or the damp-proofing measures are inadequate, it can lead to condensation and mould, reducing the insulating properties of the insulation.

In extreme cases, this can cause structural damage to the walls.


Does cavity wall insulation stop damp?

Cavity wall insulation does not guarantee that the property will be 100% waterproof, as damp can still occur due to other building defects.

Depending on the type of wall and insulation used, it can provide a degree of protection from penetrating damp but is not a complete solution to prevent it from occurring.

It will help to reduce black mould on walls caused by condensation forming on cold external walls.


Is it worth topping up cavity wall insulation?

Once installed, cavity wall insulation requires no topping up, this is because the insulation is injected to the correct density to prevent it settling or shinking.


Is cavity wall insulation a good idea?

Cavity wall insulation can be a great way to save money on your heating bill by providing an effective thermal barrier in a house.

However, it is important to ensure that it is installed correctly by an approved and accredited installer.


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