Sustainable Insulation For Your Home

It’s important to choose the right insulation for your home. There are two basic types: bulk insulation (usually batts, rolls or boards) and reflective insulation (the shiny foil).

There are many sustainable insulation products in both categories, where possible look for insulation that has a large proportion of recycled content or uses natural materials such as cellulose, polyester or bio-soluble glass fibre.

Bulk 
Organic materials generally require considerably less energy to produce than either natural or more conventional types of insulation -their inherent low carbon-footprint gives them a definite edge.

Made from recycled newspaper fibres and sold as a loose-fill product that’s blown into your ceiling space, cellulose has obvious green appeal. The product is usually treated with a mixture of borax and boric acid to make the material fire-retardant. These chemicals also deter cockroaches and silverfish. The Life Cycle Analysis (LCA) of the environmental impact of all insulation products during their total life cycle ie from their manufacture to their removal at the end of the life of a building shows that cellulose is the world’s leading sustainable insulation. 

Marketed under the name “thermafleece”, sheep’s wool is also an excellent insulator. It is breathable, absorbs moisture and has remarkable natural thermal qualities – as well as being fire resistant. Other excellent organic insulators include expanded clay aggregate, raw clay fired to produce an aggregate which is naturally fire and water resistant and perlite which is produced from volcanic materials.

Some of the more traditional “green” methods enjoying a revival include straw, hemp, cork and flax.  Like all insulators there are pros and cons to all these materials. Hemp has a natural resistance to fungus and insects and cork has a natural resistance to rotting, making both products particularly useful in specific applications. While straw scores highly for its thermal properties, its weight and susceptibility to mould does limit the uses it can be put to. 

Organic materials aren’t the only environmentally-friendly insulators; technology has gone along way in transforming some of the more conventional bulk insulators such as glasswool and rockwool into “green” products - Pink Batts by Fletcher Insulation and Bradford Insulation are two brands which have a real focus on the environment.

It’s not enough that as insulating companies they are contributing to lowering green house emissions, they have gone one step further and developed a variety of products that are sustainable in their own right. As a type of glasswool insulation, Pink Batts are manufactured from renewable sources (sand) and recycled glass (up to 70 per cent). 

Reflective
Made from bubble cell or foam centres sandwiched by two layers of highly reflective aluminium foil, thermo reflective foil insulation is another sustainable insulation option. The material works by reflecting radiant heat rather than absorbing it. Lightweight and ultra-thin (usually 6-8mm), the product is extremely sustainable as it uses less resources than some bulk insulators. 

R-value
There are many factors to consider - in addition to sustainability - when selecting the right insulation for your home. This includes cost per square metre fire resistance, whether the product can be installed DIY or professionally and of course thermal performance.  

To compare the insulating properties of the product it’s important to look at its R-value. An ‘R’ value is a measure of a material’s resistance to heat flow, generally the higher the R-value the more effective the insulation. A product’s R-value is the most accurate measure of a products true performance. All materials offer a resistance to heat transfer, they slow down the speed of heat moving through them. Good insulators have a high resistance to heat flow, so a high R-value.

The Building Code of Australia (BCA) sets out minimum requirements for materials R-values but this is dependant on the climatic zone. Visit www.yourhome.gov.au for further details and to see how your sustainable insulator measures up.

Interesting tidbit 
Sustainable insulation has come along in leaps and bounds in the last few years; two young entrepreneurs have recently even developed a renewable source of sustainable insulation from mushrooms - known as Greensulate.

With its densely packed mycelium fibers, Greensulate could eventually replace other forms of insulation. As soon as developers Eben Bayer and Gavin McIntyre are satisfied with their research and feel their technology is robust enough to meet demand there are plans for this product to be commercialised!