Sustainable Insulation Materials for Your Next Building Project

Many assume that conventional products perform better than their natural counterparts, but natural insulation materials have advantages of their own. Here are some sustainable insulation materials you can use for your home.

Insulation is important for any building project, but it is a particularly essential factor in sustainable design. Conventional materials for insulation are inexpensive to buy and install, but they generally cost a lot of energy to manufacture. Plus, they contain chemicals, like formaldehyde, that are known to be harmful in large amounts.

Many assume that conventional products perform better than their natural counterparts, but natural insulation materials have advantages of their own.

  • They are low impact, requiring low energy to produce
  • They are biodegradable
  • They are non-toxic
  • They’re breathable, which allows for regulating humidity and reducing condensation
  • They give timber parts added protection from rot

While costs can discourage homeowners, builders, and developers from using natural insulation materials, many consider them worth the investment, as not only do they impact the environment less, but they can also save money in heating technologies and in energy bills in the long run.

Here are some sustainable insulation materials you can use for your home.

Sheep's Wool

In recent years, scientists have taken the insulating properties of sheep's wool and applied them to home construction. Wool fibres are compressed to form pockets that trap air, keeping homes warm during winter and cool during summer. Wool is also good for preventing condensation.

It is important to note that while builders have used wool untreated, wool might need chemical treatment to prevent it from mite infestation. If you’d like to go completely natural and chemical-free with your home insulation, talk to your builders about using wool.


Cotton costs twice as much as fibreglass, but many homeowners opt for cotton insulation for its heat-retaining capabilities and its low environmental impact.

Cotton insulation is commonly made from recycled cotton denim. The plant it’s from is a renewable resource, making cotton among the most sustainable insulation materials available. Its capacity to retain heat is similar to fibreglass, but unlike fibreglass, it doesn’t contain formaldehyde, which scientists have linked to cancer.

Unlike most other fibrous insulation materials, cotton fibres do not cause allergies and respiratory problems. It’s also insect repellent, even without chemical treatment. As an insulation product, cotton is usually treated with boric acid as a fire retardant and antifungal agent. But unlike a lot of other antifungals, boric acid is fairly nontoxic.


Cellulose insulation is made from recycled newsprint and other cellulose fibre such as cardboard and paperboard. It contains more recycled content than most other sustainable insulation materials. When treated with boric acid, it is non-toxic and resistant to rot. Many builders like using cellulose insulation because aside from it having low embodied energy, it can be blown into wall, floor, and roof cavities, and it can double as a loose fill.

Cellulose insulation, however, does have a few issues of its own. It can absorb more moisture than most other insulation materials. This means that it is likely to get wet, and if it does get wet often, the boric acid could seep out. Not only does this take away the insulation’s fire retardant qualities; it could also cause mould to grow. Additionally, although cellulose insulation is relatively safe and chemical-free, the outgassing of newsprint ink might bother some people. For these reasons, although cellulose insulation is safe to handle, it’s best to seek the help of a professional for installation.

Spray Foam

Once notorious for using ozone-damaging CFCs, spray foam insulation now comes in vegetable-based versions. These greener versions use oils from botanical sources such as soy and sugarcane, and they do not damage the ozone layer.

Although they’re more environmentally sound, vegetable-based foams have a lower density, which means they generally insulate less effectively than their denser and more toxic counterparts. And although they’re safe and inert once cured, foam insulation outgases toxic chemicals during installation.

Some newer foam insulation materials are both effective and safe. Icynene, a type of spray foam made from castor oil, can expand up to 100 times its volume. It seals houses tightly from air leaks, stops drafts, and even muffles noise. Such tight sealing often entails having to invest in a ventilation system, which doesn’t help that Icynene by itself is already expensive. But some builders consider it worth the investment, as insulation this effective can help reduce a home’s energy consumption by up to half.

Whether you’re building or renovating, we can help you with effective and safe insulation for your home. Talk to us. Liked this article? Follow us on Facebook, Instagram, and LinkedIn.

Work with Sydney home designers.



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