What is loft and cavity wall insulation?

Loft and cavity wall insulation are energy-saving measures that reduce heat loss through your roof and external walls. Loft insulation is fitted between and over joists in your attic, while cavity wall insulation is installed in the gap between the inner and outer layers of your external walls. Together they help keep your home warmer for longer and can significantly reduce your heating bills.

How much can I save on my energy bills with loft and cavity insulation?

The exact saving depends on your property size, construction and current insulation levels, but many UK households save up to hundreds of pounds per year by upgrading both loft and cavity wall insulation. Because heating makes up the largest share of most energy bills, improving insulation usually delivers one of the fastest returns on investment and can quickly pay for itself through lower monthly costs.

Am I eligible for free or grant-funded insulation?

You may be eligible for free or heavily subsidised loft and cavity wall insulation through government-backed energy efficiency schemes in the UK. Eligibility is typically based on factors such as your household income, whether you receive certain benefits, the energy performance of your home, and your current insulation levels. Use the checker or enquiry form on the EnergyPlus website to see if you qualify and to get personalised advice.

How long does loft or cavity wall insulation installation take?

Most standard loft insulation jobs can be completed within a few hours, and cavity wall insulation in an average-sized home is often finished in less than a day. An installer will assess access, existing insulation and any preparation work required during your initial survey, so you know exactly how long the process will take and what to expect on the day.

Will the installation be messy or disruptive?

Professional installers aim to keep disruption to a minimum. Loft insulation is usually accessed via your loft hatch, and cavity wall insulation is injected from outside the property through small drill holes that are filled afterwards. There may be some minor noise and dust while work is carried out, but reputable installers will protect your home where necessary and tidy up before they leave.

How do I get a quote or survey for loft and cavity insulation?

To get started, complete the short enquiry or eligibility form on the EnergyPlus loft and cavity insulation page, or contact the team by phone or email. A specialist advisor will discuss your property, confirm whether you may qualify for funding, and arrange a free, no-obligation survey so you can receive a tailored quotation before deciding to go ahead.

Loft & Cavity Wall Insulation in the UK

Cut heat loss, lower your energy bills and make your home warmer — with professional insulation advice and installation support from EnergyPlus.

Stop Heating the Street — Keep the Warmth You Pay For

In many UK homes, up to one third of all heat is lost through uninsulated walls and roofs. Loft and cavity wall insulation are among the fastest, most cost-effective upgrades you can make to reduce energy bills and improve comfort.

EnergyPlus provides clear cost-saving advice and connects homeowners, landlords and tenants with trusted insulation installers and available grant schemes across the United Kingdom.

• Reduce annual heating costs by up to £600+ per year*
• Improve your home’s EPC rating and property value
• Enjoy a warmer, more comfortable home all year round
• Cut your home’s carbon footprint significantly

*Typical savings based on a gas-heated, semi-detached UK home upgrading from little/no insulation to recommended levels. Actual savings will vary.

Check Your Insulation Options

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What Is Loft Insulation?

Loft insulation is a protective layer of material laid in your roof space to slow down heat loss through the ceiling. In a typical uninsulated UK home, around 25% of heat escapes through the roof. By fitting or topping up loft insulation to the recommended thickness of around 270mm, you keep more warmth in for longer.

Most modern loft insulation in the UK uses mineral wool rolls or blown insulation made from glass or rock fibre. These materials trap tiny pockets of air, which significantly reduce heat transfer.

Loft insulation is ideal if:

You have an accessible loft space above the top floor.
You don’t regularly use the loft as a living space (or can insulate the roof instead).
You want a relatively quick, low-disruption upgrade with strong payback.

What Is Cavity Wall Insulation?

Many UK homes, especially those built between 1920 and 1990, have what are known as cavity walls: two layers of brick or block with a gap — the cavity — in between. If this cavity is left empty, up to 35% of heat can escape through the walls.

Cavity wall insulation fills this gap with a specialist insulating material, such as mineral wool, polystyrene beads or foam. The insulation is usually installed from the outside through small, carefully drilled holes in the external brickwork, which are filled in afterwards to leave a neat finish.

Cavity wall insulation is suitable if:

Your home was built with cavity walls (common from the 1920s onwards).
The walls are in good condition with no significant damp problems.
You want a high-impact measure that can drastically reduce heat loss.

Why Loft & Cavity Insulation Make Such a Difference

Insulation is often the first step recommended in UK home energy surveys — and for good reason.

Lower Energy Bills

By reducing heat loss through the roof and walls, your boiler or heating system doesn’t need to work as hard, cutting annual fuel bills.

Improved Comfort

Insulation helps keep your home warmer in winter and cooler in summer, reducing draughts and cold spots around rooms.

Better EPC Rating

Adding or upgrading loft and cavity wall insulation can significantly improve your Energy Performance Certificate (EPC) score.

Lower Carbon Emissions

Using less energy to heat your home means fewer CO₂ emissions, supporting the UK’s net zero targets.

Typical UK Insulation Savings & Payback

The figures below are illustrative examples for a gas-heated, semi-detached house in Great Britain upgrading from little or no insulation to recommended levels.

Measure	Typical Installed Cost*	Estimated Annual Saving*	Indicative Payback
Loft insulation (top-up or new install)	£400 – £700	£150 – £300 per year	2 – 4 years
Cavity wall insulation	£800 – £1,500	£250 – £600 per year	2 – 5 years
Loft + cavity wall insulation combined	£1,200 – £2,000	£400 – £800 per year	2 – 5 years

*Costs and savings are general estimates based on publicly available UK data and typical domestic properties. Actual figures depend on your property size, existing insulation levels, fuel tariffs and installer prices.

Grants & Funding for Loft and Cavity Insulation

Depending on your circumstances and where you live in the UK, you may be able to get free or subsidised insulation through government-backed schemes and local initiatives.

Examples of support that may be available:

ECO4 and ECO+ — energy company obligation schemes that can help eligible households with insulation and heating upgrades.
Local Authority & regional grants — councils and devolved governments in England, Scotland, Wales and Northern Ireland sometimes offer additional support.
Landlord & social housing programmes — funding or obligations to improve the energy efficiency of rental and social housing stock.

Grant eligibility can depend on factors such as household income, benefits received, existing EPC rating and property type. EnergyPlus can help you understand what you may qualify for and how to apply.

Ask Us About Insulation Grants

Is Your Home Suitable?

Most UK homes can benefit from some form of loft or cavity insulation, but the best solution depends on your building’s construction and current condition.

Loft insulation suitability checklist:

Accessible loft space with safe access.
Reasonable condition of roof structure and joists.
No unresolved leaks or significant condensation issues.
Space around electrical fittings and water tanks considered during design.

Cavity wall insulation suitability checklist:

Walls are cavity construction (not solid stone/brick).
Brickwork and pointing in sound condition.
No significant existing damp penetration or flooding risk.
Property is not exposed to severe driving rain without proper assessment.

Our recommended installers will always conduct a pre-installation survey to confirm suitability and identify the safest, most effective approach for your home.

How the Insulation Process Works

From your first enquiry to final sign-off, EnergyPlus helps make the journey simple and transparent.

1. Initial Advice

Share basic details about your home and current insulation. We’ll help you understand the best options and potential savings.

2. Property Survey

A qualified surveyor inspects your loft and/or walls, checks for any issues and confirms suitability for insulation.

3. Quotation & Funding Check

You receive a clear quotation and, where applicable, we explore grant or funding options to reduce the cost.

4. Installation & Aftercare

Accredited installers complete the work, with minimal disruption, and provide any manufacturer or installer guarantees.

Loft & Cavity Insulation — Frequently Asked Questions

Most loft insulation jobs for an average UK home can be completed in half a day to one full day. Cavity wall insulation usually takes around 2–4 hours, depending on the size and layout of the property. Your installer will confirm timings during the survey.

When specified and installed correctly on a suitable property, cavity wall insulation should not cause damp. Reputable installers carry out checks for exposure to wind-driven rain, existing damp issues and the condition of brickwork before any work is done. EnergyPlus only recommends accredited installers who follow industry guidelines and best practice.

Yes. If your loft is insulated at joist level, your installer can create raised boarding above the insulation for storage. It’s important not to compress the insulation with heavy boards or items, as this reduces its effectiveness. During your survey, you can discuss the best layout for both insulation and storage needs.

Modern loft and cavity wall insulation products are designed to last for decades. In many cases, the insulation will remain effective for the lifetime of the building. Some systems are backed by 25-year or longer guarantees from manufacturers or independent guarantee bodies.

In most cases, loft and cavity wall insulation for existing homes is considered a permitted improvement and does not require planning permission. However, installers are expected to comply with relevant building regulations, such as fire safety and ventilation requirements. Your installer will advise if any notifications are needed for your specific project.

Ready to Cut Your Heating Bills with Better Insulation?

Whether you’re a homeowner, landlord or tenant, EnergyPlus can help you understand the best loft and cavity wall insulation options for your property, what it’s likely to cost and which funding schemes you may be able to use.

Request Your Free Insulation Consultation

No pressure sales — just clear, practical advice tailored to UK homes.

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Updated on 7 Dec 2025