What Is the Most Sustainable Insulation in the UK?

Insulating your home is an upgrade that comes with a wealth of benefits. Slashing your energy bill, creating a comfortable home environment, and reducing your carbon footprint are just some of the perks you can enjoy with this handy investment. 

However, not all home insulation materials are sustainable. While providing your home with better heat retention, some synthetic materials cancel out the positives with their environmental risks and lack of recyclability. So what materials are most sustainable to use as insulation?

This ultimate guide by GreenMatch UK will explain everything you need to know about eco-friendly insulation materials on the UK market, their properties, benefits, and more.

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There is a wide range of environmentally friendly insulation materials on the UK market today, each boasting various suitability, properties and price ranges. The most sustainable materials today are recycling-based materials, such as cellulose and wood wool.

Alternatively, you also have nature-derivative materials, such as cork board, or hemp wool, made from all-natural products. While these are just as environmentally friendly, various degrees of sustainable production are worth considering.

Ultimately, there are plenty of good insulation materials for the job, each with its properties, pros, and cons to consider, which make choosing the single most sustainable material difficult. 

To help, here’s a breakdown of the top sustainable insulation materials you may find today:

All natural, renewable, and sustainably produced, corkboards are some of the most environmentally friendly material options for insulation. Costing around £17 - £22 per m2, corkboard boasts impressive thermal retention, material durability, and even properties such as moisture and flame resistance. 

The only downside may be that the corkboard has a higher price tag, but this is compensated for by its exceptional thermal performance.

This loose-fill material is made entirely from recycled paper and wood products, making it a great choice for eco-conscious insulation measures. Costing around £10 - £12 per m2, cellulose is also one of the most affordable insulation materials available today. 

Cellulose is often used as insulation for loft spaces that aren’t as accessible. As a con, cellulose is a lot more fire and moisture-prone than other materials, but a professional insulation job can help avoid such problems easily.

Praised for its contribution to home health, sheep wool is a more traditional yet just as effective solution for home insulation. Costing £17.5 - £22 per m2 of treated wool, this material is hypoallergenic, releases no harmful toxins, and is entirely biodegradable. 

One key detail to look out for is to make sure your wool is treated. Failure to do so can cause an infestation, as pests may choose to burrow and nest in the sheep wool. Luckily, the majority of insulation-prepped sheep wool will be pre-treated for the purpose.

Hemp wool is made from the fibres of the hemp crop, one of the most versatile and fast-growing crops in the world. Costing between £10 - £25 per m2 depending on the material density and thickness, hemp wool is biodegradable, durable, and non-toxic.

As a downside, hemp wool has poor fire and moisture resistance when compared to other eco-materials, but a professional insulation job goes a long way in preventing such issues.

Made from recycled rock or glass, mineral wool is one of the most popular insulation materials on the market, and for good reason. Costing around £13 - £17.5 per m2, mineral wool can be sustainably produced and it's a recyclable insulation material. 

It also boasts flame and mould resistance and has decent thermal efficiency, making it a popular option for insulating walls, especially cavity wall insulation. The main downside is that mineral wool can cause mild to severe skin irritation or respiratory difficulties if handled without necessary protective gear.

Similar in consistency to mineral wool, fibreglass is made of recycled glass products that have been woven into strands to make blanket-like sheets. Costing around £10 per m2, fibreglass is one of the most budget-friendly sustainable materials.

As a con, fibreglass is less thermally efficient than other materials and will require a larger thickness to achieve desired heat retention. Nevertheless, its very favourable price tag makes it a popular option for sustainable insulation measures.

Sometimes also called blue jean insulation, denim has become a popular material to repurpose into insulation sheets and compressed boards. Costing a hefty £50 - 60 per m2, these are made by recycling old denim products and transforming them into loose cotton strands. This is then compressed to form sheets and boards.

Due to denim dye being notoriously toxic for the planet, denim insulation is a great sustainable way of repurposing and reducing textile waste. However, the downside would be its price tag, surpassing common insulation materials in investment.

While polyurethane (PU) spray foam is known for its toxicity and harm to the environment, there are several bio spray foam worth considering. Some examples are Icynene foam insulation, which is castor oil-based, or Soy foam made from soybean. 

As a con, these bio-spray foam alternatives tend to cost quite a penny. Standard polyurethane spray foam costs around £21.5 per m2, and bio alternatives may cost even more due to the complexity of the manufacturing process.

This isn’t an exhaustive list of eco-materials, and there are far more unique and experimental sustainable insulation materials on the market. New ones are emerging every year as energy conservation and sustainability become important focus points. 

Sustainable insulation materials are not just beneficial for your home, but also for your health and the planet at large. Huge savings, home comfort and sustainability are just some of the benefits you could enjoy. Here’s some more:

With all there is to be gained, it’s also important to acknowledge that poor insulation decisions can quickly become a financial nightmare. For example, a shabby DIY job can leave you paying more for repair costs than your initial insulation. That’s why we recommend working with a professional installer who can create a tailored course of action for your home.

However, finding the right installer is no easy task. Prospective customers often find themselves stuck in an endless loop of vetting installers via websites and phone calls. Luckily, GreenMatch UK can free you from this burden.

Spend just 30 seconds filling out our online form, and we’ll send you up to 3 free home-tailored quotes from our nationwide network of accredited professionals. No charges or obligations apply. Click below to begin!