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How much does it cost to insulate my home and is it worth it?

Ashton Berkhauer
Written by  Ashton Berkhauer
Collette Shackleton
Reviewed by  Collette Shackleton
4 min read
Updated: 25 Apr 2025

Read our guide to find out how insulating your home could save you money

Key takeaways

  • Loft insulation starts from £300 and cavity wall insulation from £400 in the UK, with floor and solid walls costing significantly more, depending on factors like the size and age of your property

  • Fibreglass and mineral wool rolls are a budget-friendly option for lofts and stud walls

  • Great British Insulation Scheme (GBIS) and Energy Company Obligations (ECO) scheme offer free or subsidised insulation for those on certain benefits

Woman in bed using a tablet

Where does your home need insulation?

There are certain areas of your home that need insulation, including: 

They account for a third of heat loss, but with cavity wall insulation, you can significantly reduce this. Cavity walls are exterior walls with two layers and a narrow gap in between. They lose less heat than solid walls, but can still be improved with insulation.

A quarter of heat escapes here, but loft insulation can keep that heat where it belongs.

They might be underfoot, but don't overlook them; 10% of heat loss can occur here.

Windows, doors, and chimneys can be sources of heat loss if not properly draught-proofed.

Types of home insulation 

There are different types of insulation materials available, depending on which area of your home you're insulating. The most common materials include:

A popular choice due to its affordability, often used in batts or rolls, relatively easy to install.

Similar to fibreglass but made from rock or slag, offering good insulation and fire resistance.

Made from recycled paper, a more eco-friendly option, often used for loose fill in walls and lofts. 

These come in various forms like polystyrene, polyurethane, or PIR, offering high R-value and good moisture resistance, suitable for walls, floors, and roofs. 

Applied by professionals, spray foam creates a continuous insulation layer, effectively sealing gaps and air leaks.

Materials like fibreglass, mineral wool, or cellulose can be blown into wall cavities and lofts, providing insulation where access is limited. 

How much does home insulation cost?

The cost of house insulation varies widely depending on the type of insulation, the size and type of your home, and whether you are insulating walls, lofts, or floors.

Generally, you'd expect to pay anywhere from £300 for loft insulation to over £14,000 for external wall insulation on a larger property. 

Type of insulation

Average installation cost

Estimated annual energy savings

Benefits

Loft insulation

£300 – £500

£150 – £250

One of the quickest returns on investment

Cavity wall insulation

£400 – £800

£120 – £270

Great for homes built after 1920s

Solid wall insulation (internal)

£4,000 – £7,000

£250 – £450

Higher cost but significant energy savings

Solid wall insulation (external)

£8,000 – £12,000

£260 – £480

Improves appearance too

Floor insulation

£1,200 – £2,000

£60 – £120

Best for ground floors and basements

Draught proofing

£100 – £200

£20 – £50

Simple, low-cost energy saver

What home insulation grants are currently available in the uk?

​As of April 2025, UK residents have access to several government-backed energy schemes offering free or subsidised home insulation to improve energy efficiency and reduce heating bills.

The main schemes currently available are:​

Launched in April 2023 and running until March 2026, GBIS (formerly ECO+) is a £1 billion initiative aimed at helping households insulate their homes.

It targets properties with low energy efficiency (EPC ratings D–G) and Council Tax bands A–D in England (A–E in Scotland and Wales). The scheme offers free or heavily discounted insulation measures, including:​

  • Loft insulation

  • Cavity wall insulation

  • Solid wall insulation (internal or external)

  • Underfloor and solid floor insulation

  • Room-in-roof insulation

Eligibility is divided into two groups:​

  • General Group: Households meeting the EPC and Council Tax criteria may receive a single insulation measure, with a possible contribution required.​Wikipedia

  • Low-Income Group: Households receiving certain means-tested benefits may receive a single insulation measure, potentially including heating controls, with no contribution required.​Wikipedia

To check eligibility and apply, visit the official GBIS page on GOV.UK.

Running until March 2026, ECO4 is a long-standing scheme obligating large energy suppliers to fund energy-saving measures for low-income and vulnerable households.

It focuses on improving the least energy-efficient homes (EPC ratings D–G) through a whole-house approach, which may include:​

  • Insulation (loft, cavity wall, solid wall)

  • Heating upgrades

  • Solar panels​

Eligibility typically requires households to receive certain income-based benefits, such as:​

  • Universal Credit

  • Pension Credit

  • Income Support

  • Child Tax Credit

  • Working Tax Credit​

Local authorities can also refer households under the ECO4 Flex scheme. For more information, visit the Ofgem ECO4 page.

Offers up to £15,000 for energy efficiency upgrades in low-income households.

What are the benefits of insulating your home?

There are many advantages of insulating your home, such as:

  • Reduced energy bills

  • Smaller carbon footprint

  • Warmer and cooler home throughout the changing of the seasons

  • Noise reduction

  • Improved air quality

  • Moisture control

  • Increased property value

Is home insulation worth it in the UK?

Yes, although the initial investment cost is quite high, home insulation in the UK is generally worth it long term. It offers significant cost savings and other benefits. Insulating your home can reduce heat loss, lower energy bills, and improve comfort and health.

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Frequently asked questions

Which insulation is best for old houses?

For insulating old houses, mineral wool (like rockwool or glasswool) is often the best choice, especially for cavity walls, as it's breathable and fire-resistant.

Other good options include sheep's wool or hemp, which are natural, renewable, and breathable. Cellulose insulation, made from recycled paper, is also a good, environmentally friendly option, especially for blown-in applications.

What is the cheapest way to insulate a house?

The cheapest way to insulate your home on a budget is to focus on areas with significant heat loss, like windows and doors, and use cost-effective materials like draught-proofing and thermal curtains.

If you need to upgrade your loft insulation or install floor insulation with underlay, check if you're eligible for free insulation grants.

How long does home insulation last?

Home insulation can last between 15 to 100 years, depending on the material and installation quality. Fibreglass and cellulose insulation typically last 20-30 years, while mineral wool and spray foam can last up to 100 years. Cavity wall insulation is designed to last the lifetime of the building, often 20-100 years.

Is cavity wall insulation still recommended?

Yes, insulating cavity walls is generally recommended. By filling the gap between the two walls of a cavity wall, you can significantly reduce heat loss, saving money on heating bills and reducing your carbon footprint.

However, it's crucial to ensure proper installation and address any existing damp issues before proceeding, as incorrect installation can lead to damp problems.


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