Everything you need to know about eco-friendly insulation

Insulation is a key building component that keeps our homes energy efficient and saves on fuel bills. However, with conventional insulation packed with adhesives and chemicals, many homeowners are now switching to eco-friendly insulation instead.

Here, we share everything you need to know about going green with your insulation. There are also tips on finding an insulation installer near you.

Why choose eco-friendly insulation?

Advancements in eco-friendly insulation (also known as green or sustainable insulation) have come on leaps and bounds. Nowadays, there are many options to choose from.

Benefits of choosing eco-friendly insulation include:

• Cost savings – Increasing the energy efficiency of your home means a reduction in your energy bills
• Keeps your home warmer – According to the Energy Saving Trust, 33% of heat is lost through uninsulated walls
• Kind to the planet – Some types of standard insulation may take up to ten times the energy to produce than green options. Eco-friendly insulation only requires small amounts of energy to produce and is also recyclable
• Safety – Green insulation doesn’t contain chemical fire retardants and other additives, meaning you’ll be improving your air quality
• Increase the value of your home – A well-insulated home is attractive for home buyers keen to reap the benefits of an insulated home without the cost or upheaval of fitting insulation retrospectively

Best eco-friendly insulation options for UK homes

There are many types of green insulation on the market today, and each material has its own benefits. That’s why picking the right option for your home requires a little research.

Let’s run through the most popular eco-friendly options, along with some pros and cons:

1. Recycled cellulose insulation

• Qualities – Made from recycled newspaper and other plant-based fibres. Its loose-fill or blown-in application makes it ideal for lofts and cavity walls
• Pros – Very affordable, fireproof and offers great heat insulation
• Cons – Susceptible to moisture damage if not properly installed. Also, the manufacturing process uses more energy to make it fire-resistant, so it might not be as ‘green’ as some of the other options
• Cost – Prices for recycled cellulose insulation (100mm thick) start at £12 per square metre

2. Sheep wool insulation

• Qualities – 100% natural and biodegradable. It’s often used for insulating solid walls and timber-frame homes
• Pros – Resistant to mould and fire and very insulating
• Cons – More expensive than some synthetic options and can attract moths if not properly installed and treated
• Cost – Prices for sheep wool insulation (100mm thick) start at £12.50 per square metre

3. Cork insulation

• Qualities – Harvested from the bark of cork oak trees, this is one of the most sustainable options. It comes in boards or rolls, so it offers flexibility when installing
• Pros – Great at reducing noise pollution, damp-proof, lightweight and long-lasting
• Cons – More pricey and harder to come by than other eco-friendly options. It’s also prone to crumbling if installed incorrectly
• Cost – Prices for cork insulation (100mm thick) start at £60 per square metre

5. Wood fibre insulation

• Qualities – Made from wood chips and sawdust, it’s available in boards or flexible batts
• Pros – Excellent soundproofing qualities, breathability reduces the risk of damp and mould
• Cons – It is heavier than other eco-friendly insulation options, so might not be suitable for all homes
• Cost – Prices for wood fibre insulation (100mm thick) start at £33 per square metre

6. Glass wool (aka fibreglass or blanket) insulation

• Qualities – Manufactured with recycled glass
• Pros – Cost-effective and non-flammable. It’s possible to install yourself, though you’ll need to invest in professional protective gear as fibreglass can irritate your skin or lungs if inhaled
• Cons – The making of fibreglass is an energy-intensive process
• Cost – Prices for glass wool blanket insulation (100mm thick) start at £22 per square metre

Other green insulation types include eco-friendly spray foam made from non-toxic, renewable liquid (not to be confused with the 70s version, which is prone to ventilation issues and dampness), hemp, and denim.

If in doubt, an experienced insulation specialist can advise on the best option for your home.

What type of eco-insulation is best for your home?

1. What’s the insulation for?

Insulation options include everything from walls and floors to roofs and lofts. Let’s look at some of the most common insulation jobs:

• Lofts – You’ll want something lightweight and flexible, like sheep wool or glass wool
• Walls – Wood fibre insulation might be the best option. Supplied in large sheets, it’s heavy-duty and will provide a neat finish

2. What wall type do you have?

Whether your home has solid walls (most common in pre-1920s homes) or cavity walls will significantly impact the type of eco-friendly insulation you choose:

• Solid walls – Generally speaking, sheep wool insulation is considered the best option for solid walls
• Cavity walls – Recycled cellulose is a great option for filling cavity walls due to its flexibility. Loose-fill or blown-in applications are both possible with cellulose insulation

3. What qualities are most important?

Is your home currently plagued by dampness and mould? Or is your chief concern energy efficiency? Shop around and choose the best green insulation to match your home’s needs:

• Dampness and mould – Breathability is an important quality to look for to help regulate humidity levels and prevent condensation. Wood fibre and sheep wool are both good options
• Thermal performance – Look into sheep wool or recycled cellulose, which both retain heat very well
• Sound insulation – Cork insulation can help minimise noise disruption alongside retaining that vital heat

4. What’s your budget?

As explored briefly above, the cost of eco-friendly insulation can vary hugely:

• Most expensive – Expanded cork board insulation is the most expensive at £60 per square metre
• Cheapest – Loose-fill cellulose insulation comes in the cheapest costing £12 per metre and can be installed yourself. However, if you’re not a confident DIY-er, we always recommend getting a professional to do the job.

To help you budget confidently, next we look at some approximate costs.

How much does insulation cost to be installed by a professional?

Upgrading your home’s insulation is a worthwhile investment that will save you money and help the environment.

Getting some ballpark figures is handy before contacting a tradesperson to install new eco-friendly insulation. Some approximate costs for insulation in the home include:

Cavity wall insulation

• Cost: The average cavity wall insulation cost is between £950 – £4,600 (depending on the size of your property)

Solid wall insulation

• Cost: On average, external wall insulation costs between £6,000 – £25,000 (depending on the size of the property)

Loft installation

• Cost: Loft insulation starts in the region of £725 for basic quilt installation.

However, it’s important to note these are approximate costs, and how much you pay for your insulation upgrade will depend on various factors. That’s up next.

Factors affecting the cost of your eco-friendly insulation

How much you’ll pay for eco-friendly insulation will depend on numerous factors, including:

• Where the insulation is being fitted in your home
• The type of insulation you choose
• If you need to remove existing insulation
• How large your home is
• Where you are in the UK

For more context, our cavity wall insulation cost guide and our loft insulation cost guide both have average figures you can expect to pay.

Are the costs mounting up more than you hoped? Before scrapping your insulation plans entirely, it’s worth checking if you’re eligible for some of the government grants below.

Grants and funding for eco-friendly insulation

You may be eligible to apply for grants depending on where you live in the country and your home circumstances.

The good news is various certified installers, local authorities, energy companies, and other bodies can help with the cost of your external wall insulation – as long as you know where to look.

Here are some current schemes to check out:

• ECO4 (Energy Company Obligation) scheme – Lasting until 2026, this grant has the potential to shave 25% off your quote for external wall insulation
• The Great British Insulation Scheme – Scheduled to run until 2026, it provides free or cheaper insulation to help households reduce their energy bills
• The Warm Home Local Grant – Providing funding for local authorities to deliver energy performance and low-carbon heating upgrades to low-income homes in England. Applications open in April 2025
• 0% VAT – While not a grant, the UK government offers 0% VAT on installing eligible energy-saving home upgrades until March 2027

Our green grants guide has the most up-to-date information about the schemes available, including eligibility criteria and how to apply.

An experienced insulation installer will also be able to help advise you on the current grants available and if you might be eligible. Keep reading to find an insulation expert specialising in eco-friendly options near you.

Your eco-friendly insulation summary

• Recycled cellulose and sheep wool insulation are considered the most eco-friendly
• If you want to insulate your home naturally and improve your air quality, sheep wool and cork are best
• If you live in wetter, more damp environments (for instance, coastal towns), cork has excellent moisture-resistant qualities
• An experienced eco-friendly insulation installer is best placed to advise on what type is right for your home

Ready to give the green light on your eco-friendly insulation project? Search your postcode below to get started.