A Complete Guide to ECO-Friendly Insulation

guide to eco friendly insulation

If you are considering insulation, one of your main concerns, aside from reducing your heating bills, might be reducing your actual carbon footprint. The good news is that the insulating material itself can also be green, as in environmentally friendly.

Natural fibre insulation is the most environmentally friendly option to make your home more energy efficient. In most cases, less energy is required in the production of eco-friendly insulation, which minimises its carbon footprint.

Although eco-friendly insulation is commonly seen in newer construction, it is adaptable to any building style and can be installed retrospectively. In addition to decreasing a home’s environmental impact, most eco-friendly insulation products are fire-resistant and help delay the spread of a house fire.

Eco-friendly Insulation Alternatives

Some of the most common eco-friendly insulation solutions are treated sheep’s wool, which performs extraordinarily well as an insulator, and recycled plastic bottles reformed into insulation rolls. Both types of insulation are excellent thermal insulators, with sheep’s wool providing additional acoustic insulation.

Most homeowners leave the insulation selection to contractors. After all, insulation isn’t exactly aesthetically pleasing. However, a new wave of eco-friendly insulation choices has emerged, and they are well worth investigating for your green building or remodelling project.

Because insulation is intended to lower energy consumption, any insulation might be considered green. However, eco-friendliness also needs to take into account other factors such as production method including materials used, toxicity and carbon footprint.

Fibreglass insulation, is usually the least expensive alternative, but it is not particularly environmentally friendly. Fibreglass insulation production can require up to ten times more energy than some eco-friendly alternatives.

Furthermore, fibreglass insulation includes harmful filaments related to health problems such as skin, eye, and respiratory irritation. While fibreglass insulation can contain up to 30% recycled glass, it is far behind other insulation alternatives that may contain up to 80 per cent recycled material.

For many people, choosing the type of insulation for their home is about more than which is the most effective or even the cheapest option. With green credentials and other factors to take into account when it comes to eco-friendly insulation options, we provide you with the low-down so you can see how some of the eco-friendly insulation alternatives can minimise your energy expenses, energy use, and carbon emissions.

Benefits of Eco-Friendly Insulation

Materials that are safe and durable

Eco insulation materials are the ideal choice for the household that wants to be greener and healthier. Insulation made from natural materials such as wool and cotton do not cause irritation to the skin or any respiratory issues that can result from using some other types of insulation like fibreglass.

Opting for insulation made from recycled materials is also beneficial to the environment because it positively impacts your carbon footprint. Effectively you would be choosing material that would have been destined for landfill.

Reduced Manufacturing Costs

Compared to fibreglass insulation, insulation materials like wool and cork require very little energy in their production. Fibreglass insulation is energy intensive in its production, requiring up to 10 times the energy to make than cellulose insulation. Reduced energy consumption during production results in less carbon emissions.

Savings on Energy

While fibreglass insulation does perform well and have a high R-value, it is less eco-friendly and not from a sustainable source. Green insulation options are not only safer and more sustainable; they may sometimes provide significantly more insulation per square inch, bringing bigger potential savings on energy bills.

What is the best eco-friendly insulation?

There are essentially two types of environmental insulation. The first is natural insulation, which does not require manufactured chemicals to be formed and hence is less likely to discharge contaminants into your home. They are also more likely to biodegrade and have a lower carbon footprint at the end of their lives.

However, it is important to note that natural insulation has limitations and should not be used in brick and block structures, block and hollow constructions, or below the damp proof course.

Recycled insulation is the second type of eco-insulation. This uses existing manufactured materials, eliminating the need for new manmade materials and the use of virgin resources while preventing recyclable materials from ending in landfill.

Different eco friendly insulation types
Image: Eco friendly insulation

#1 Sheep Wool

Sheep’s wool is not only a renewable natural resource but also possesses some properties that make it an excellent material for making interior wall insulation.

With the exception of the aforementioned natural insulating constraints, sheep’s wool insulation is made in sheet form. It has a number of the same uses and applications as mineral wool insulation in the home. Although thermal conductivity is equivalent, sheep’s wool has significant advantages.

Wool’s keratin can react with and neutralise indoor air contaminants like formaldehyde, improving indoor air quality.

#2 Recycled Materials

While there are numerous types of recycled insulation material, when we talk about recycled insulation, we mostly mean insulation created from recycled PET derived from plastic bottles.

But, with natural insulation solutions typically providing superior thermal efficiency, is there any purpose in using recycled insulation instead? While natural fibres are renewable, their supply is finite. Therefore, we also need lower environmental impact insulation alternatives to use where the benefits of using natural fibres are marginal.

Recycled insulation may also be a cost-cutting measure for your project, as it is often less expensive than natural, manufactured insulation that uses virgin materials.

#3 Straw Bales

Straw bale has a lengthy history as a construction material, but its applications are continuously evolving to this day. Straw bales insulate similarly to sheep’s wool, with air gaps forming a thermal break in the fibre.

Straw bales can be utilised in various ways to provide insulation for a house or extension. First, there’s the weight-bearing approach, in which the straw serves as a framework, insulation, and a surface for plaster.

This is a specialised style of construction that does not require a frame.  The straw is only utilised as insulation and as a surface for plaster in the infill or timber frame method.

#4 Hemp Insulation

Hemp insulation may be slightly more expensive than other options for insulating your home, but you may find it worthwhile with comparable heat conductivity and excellent sustainability credentials. Hemp can be farmed on poor-quality ground with minimal pesticide application to provide commercial crops.

Technical fibres can be obtained from the main hemp plant stalks and utilised in quilted insulation. Still, they are especially suitable in materials such as hemp line plaster or hempcrete as a fibre component, offering better insulating performance in the components in which it is used.

Cork is an intriguing material for insulating your home’s walls and flooring. It has excellent thermal qualities and is resistant to difficulties like moisture, and it is a fast-growing, naturally occurring material, which contributes to its sustainability. It also has a shallow overall carbon footprint.

There are concerns about the usage of cork because excessive bark harvesting has severely reduced the number of cork trees worldwide.

#5 Cork

Cork is an intriguing material for insulating your home’s walls and flooring. It has excellent thermal qualities and is resistant to difficulties like moisture, and it is a fast-growing, naturally occurring material, which contributes to its sustainability. It also has a shallow overall carbon footprint.

There are concerns about the usage of cork because excessive bark harvesting has severely reduced the number of cork trees worldwide.

#6 Wood Fibre

Wood fibre insulation may have more development invested in it than any other natural insulator.  There are products available for every application, including waterproof boards for roof sarking.

Wood fibre insulation comes in a number of forms, including rigid and semi-rigid boards and wool-like rolls; the rigid boards offering some interesting uses for natural insulation in housebuilding.

You don’t need a frame to support rigid wood fibre insulation, and it can be installed against solid walls and over rafters with no need for supporting timbers. Thermal bridging is reduced in both applications because a continuous insulation layer can be installed.

#7 Cellulose

Cellulose Insulation
Image: Cellulose Insulation

Cellulose is made from recycled newspaper that has been treated with (typically) boric acid to keep insects, fungi, and rodents at bay. It comes loose or wet, blown into timber-frame internal walls.

This sort of insulation is commonly employed in timber frame buildings where it may be blown into voids under air pressure.

Because the installation cost is expensive in comparison to the material, cellulose is most cost-effective when applied in larger properties or projects with above-average depth timber frames.

Cotton Insulation
Image: Cotton Insulation made from Recycled Jeans

#8 Cotton

Cotton insulation is made from recycled clothing, most commonly denim. It, like cellulose, is treated to repel insects, rodents, and fungi and is available in rolls or loose.

Cotton insulation is relatively inexpensive and has a minimal carbon footprint because denim recycling requires little energy. Inno-Therm is denim insulation comprised of 85% recycled denim and held together with a polymer binder. Three pairs of jeans are thought to be needed for each m² of denim insulation.

While its K-value is not as low as mineral wool in terms of thermal conductivity, it is still an appealing choice with excellent thermal qualities.

#9 Polystyrene

Polystyrene Insulation
Image: Polystyrene Insulation

Polystyrene is a kind of plastic. Although plastic is not traditionally considered green, it is in this case since its R-values are high, meaning it saves a lot of energy. It is available in the form of spray foam or foam board (which can add structural stability to walls).

#10 Icynene

Icynene is a form of spray foam insulation manufactured from castor oil that expands over x100 its volume when blown onto a surface. The material not only seals leaks and draughts well but also has good noise-reducing properties.

Icynene is around three times the price of fibreglass. However, this effective insulation method could reduce energy bills by up to 50%, saving you significant amounts on heating bills in the long term.


Choosing insulation type is very much a personal choice, and one based on many different factors. Each person’s situation is unique, and aside from your approach and preferences regarding green matters, there are also practical considerations with insulating materials, such as R-value and cost, to take into account.

For the eco-conscious household, there are thankfully lots of viable options for insulation that will provide good levels of thermal insulation without overly costing the environment or your pocket.

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