How Much Does External Wall Insulation Cost in 2024

External wall insulation is one of the most effective methods to improve your home's energy efficiency, reduce heat loss, and significantly lower energy bills. By installing external insulation, you can cut heat loss by up to 35% and save between £140 and £700 annually on energy costs.

However, external wall insulation cost can be substantial, making it crucial to understand the factors that influence pricing. Various elements contribute to the overall expense, from the size and type of your property to the materials chosen and the labour required.

This guide will explore these factors in detail, offering a comprehensive breakdown of what you can expect to pay for external wall insulation. By understanding the external insulation costs involved and how to budget effectively, you'll be better equipped to decide whether this investment suits your home.

If you're ready to move forward with external wall insulation and want an accurate estimate of costs while working with the best insulation specialists, GreenMatch is here to help. Fill out our quick 30-second form, and we'll connect you with up to four free quotes from top insulation experts in your area. No hidden fees, no obligations. Click the button to begin.

In the UK, external wall insulation costs between £6,000 and £22,000, depending on your property. For a 3-bedroom semi-detached home, the average cost is around £11,000. The total cost is influenced by factors such as property size, materials used, installation complexity, finishing options, and location.

More materials are needed to cover the increased exterior wall space when insulating larger homes. This can raise project costs. Furthermore, due to the size and height of the property, extensive scaffolding may be required, leading to added complexity and expenses. 

Architectural features such as multiple stories, bay windows, and extensions also increase labour costs. They may need more expensive materials due to the extra work and precision involved.

On the positive side, larger homes can potentially save more. Below is a breakdown of the external wall insulation prices and savings for different property types.

When planning to insulate your external walls, understanding the cost per square metre is crucial for budgeting. The UK's average external wall insulation cost per m² is around £100. This price includes the cost of materials, labour, and installation. However, the final cost can vary depending on the type of insulation material you choose.

Here are the prices of the top exterior wall insulation materials used in the UK:

Consider using EPS boards to reduce your external wall insulation costs. EPS is known for being the cheapest wall insulation material available due to its simple production process and easy installation. It is widely used in packaging, construction, and insulation industries, benefiting from broad application and high production volumes that drive down costs through economies of scale.

Understanding the breakdown is essential for accurate budgeting when planning for external wall insulation costs. External wall insulation involves multiple layers, each contributing to the overall expense. While you can choose materials that fit your budget, the costs of additional layers must be factored in:

It's essential to consider labour costs in addition to material costs. Professional installers usually charge around £250 per person per day. For larger properties or more complex projects, labour costs will increase. Unlike other insulation projects, it is not recommended to attempt DIY external wall insulation due to its complexity.

If your home has more than one story or hard-to-reach areas, scaffolding will be necessary. The cost is typically between £200 to £500 per week, including both the erection and dismantling of the scaffolding. Additionally, if the insulation work generates significant debris, you may need to hire a skip. The cost of hiring a skip can range from £125 to £320 per week, depending on the size of the skip needed.

Planning permission may also impact costs. While external wall insulation generally falls under permitted development, if your home is listed or in a conservation area, you'll need to apply for planning permission, which has a flat fee of £548, increasing if the site exceeds 0.5 hectares.

Several factors significantly influence the overall cost when budgeting for external wall insulation costs. Understanding these can help you budget more effectively and choose the best options for your home.

Walls in poor condition may require repairs before insulation can be applied, adding to the project's overall cost. Cracks, dampness, or structural issues must be addressed to ensure the insulation performs effectively. Patch repairs can add between £100 to £400 to your external wall insulation costs. This can increase depending on the extent of damage on your external wall.

You won't need planning permission for most external wall insulation projects as they are considered permitted development. However, if your home is in a conservation area, is a listed building, or has unique architectural features, you may need to obtain planning permission.

In the UK, the cost for planning permission is typically around £548. However, the price can increase if the site area exceeds 0.5 hectares. The fee for sites between 0.5 and 2.5 hectares is £624 per 0.1 hectare. For sites over 2.5 hectares, the cost is £15,433, plus an additional £186 per 0.1 hectare, with a maximum fee of £202,500. It's important to note that the planning process can also extend project timelines and add complexity.

The size of your property is a significant factor. Larger homes have more external wall areas, requiring more insulation material and increasing labour costs. For multi-story homes, the need for scaffolding further adds to overall external wall insulation cost.

Weather conditions can also impact external wall insulation costs. If you reside in an area prone to severe weather conditions, such as heavy rain or high winds, extra protective measures may be necessary during installation. This could result in extended project timelines or installation delays, increasing labour costs and potentially requiring more weather-resistant materials.

The ease of access to your property and the walls to be insulated can influence costs. Difficult-to-access areas may require special equipment or additional labour, increasing the overall cost. Transportation of materials in remote areas may also increase the overall external wall insulation costs.  The cost of materials, labour, and permits can vary depending on your location within the UK, with prices generally higher in urban areas or regions with a higher cost of living.

External wall thickness enhances thermal efficiency, though it comes at a higher initial cost. Insulation thickness typically ranges from 50mm to 100mm. While opting for thinner insulation may seem more cost-effective initially, it offers lower thermal efficiency. For example, 50mm thick insulation can reduce energy bills by approximately 30%, In comparison, 100mm thick insulation can reduce cost by up to 50%.

Although thinner insulation may appear cheaper upfront, investing in thicker insulation provides more substantial long-term savings. Upgrading from 50mm to 100mm insulation typically adds only about £200 to the overall cost, making it a valuable investment for improved energy efficiency.

The choice of external finish, render or cladding also impacts the price. Render is usually more affordable but may need more maintenance in the long run. On the other hand, cladding offers durability and a modern appearance but comes at a higher price. On average, you can expect to spend around £14 per m² on rendering external wall insulation. Still, this cost can increase depending on the material you choose.

The type of external finish you choose, such as decorative render or specific cladding, can also impact the overall cost. Custom or high-end finishes will be more expensive than standard options. While, on average, it can cost between £10 to £20 per m², adding decorative finishes can increase your property's appeal and increase your home's value.

Depending on the size of the project, you may need to hire a skip to manage waste and debris. Skip hire typically costs between £125 and £320 per week, depending on the size needed. Additionally, any preparatory work like removing old render or fixing wall damage will add to the cost.

External wall insulation is a highly effective way to improve your home's energy efficiency significantly, but it can be costly. The high external wall insulation cost is mainly due to the complex installation process, which includes multiple layers such as insulation boards, adhesive, reinforcing mesh, render, and a final finishing layer. This thorough process ensures that your home is well-insulated against heat loss and has the potential to save you up to £700 annually on energy bills.

The overall external wall insulation cost is further influenced by factors such as the quality and type of materials used, the size and condition of your property, and the necessity for skilled labour, often involving scaffolding and professional installers. While the initial investment may be steep, the long-term savings on energy bills and the enhanced comfort within your home make it valuable.

Fortunately, various grants for external wall insulation are available to help offset these costs, offering financial assistance to eligible homeowners and reducing the upfront burden. These grants can cover part or even all of the expenses, making external wall insulation more accessible to those aiming to improve their home's energy efficiency. To be eligible for these grants, engaging a certified insulation specialist is essential, as UK government grants are only available for work carried out by installers with PAS 2030 – 2035 certification.

To find the best certified external wall insulation installers in your area, click below and fill out our quick 30-second form. We'll connect you with up to four free quotes from installers that match your budget and needs. No hidden costs, no obligations. Click below to get started.