Insulation Products

Building insulation has become an important consideration in the New Zealand environment for a range of reasons.

The energy-saving effects of well-insulated homes and offices has been well and truly proven, but there are also considerable health gains from well-insulated buildings.  Significant health issues arise from poorly insulated houses, and New Zealand trials have shown major savings in hospitalisation costs where houses are well insulated, particularly for people over 65 with coronary conditions and for young children.

Warm homes reduce the amount of disease-promoting moisture inside the house but comfortable conditions also contribute to mental wellbeing, and considerable work has been done in recent years in New Zealand to encourage homes to be insulated, including government subsidies for installation.

Savings from insulation have also been shown to well-exceed the cost of the materials and labour involved in insulating a house.

Environment Choice New Zealand developed the Building Insulants specification to provide reassurance to New Zealanders buying insulation products that the products were environmentally preferable, ie that they met standards around materials sourcing and manufacturing as well as installation and disposal.  Licensing initially covered only thermal (heat) insulation but the coverage has been expanded recently to include acoustic (noise) insulation.

Within the Eco Choice Insulation Products group, there are three main materials used for both thermal and acoustic insulation products that are covered by the specification: natural (sheep’s) wool; glass wool; and polyester. Cellulose (paper), mineral wool (from rock or slag), polystyrene and foams (eg polyisocyanate or polyurethane) may also be used to make insulation products, and are included in the scope of the Eco Choice Building Insulants specification.

Four companies currently have insulation products licensed by Eco Choice Aotearoa: Pink Batts, Bradford, and Premier Insulation (all glass wool) and Mammoth (polyester-based insulants).

For most building products, the greatest environmental impacts happen during the manufacturing stage of the product’s life cycle.  But for thermal insulation products a significant environmental impact occurs during their use, when they can potentially reduce energy consumption used to heat or cool the building.

Achieving good thermal performance once installed is thus critical to the overall environmental impact of the product, and factors that can affect that performance include accurate and informative labelling, correct handling and correct installation. Installation is particularly critical since a gap as small as 5% can lead to a 50% reduction in thermal performance.

The manufacturing processes for both thermal and acoustic building insulants are very similar.  Thermal products can have some acoustic insulation qualities and vice-versa, though acoustic insulation is typically denser than its thermal counterpart.

The different materials used to make insulation products do present different environmental issues in their manufacturing and those issues are reasonably significant. 

• Sheep’s wool
  Sheep’s wool is clearly a renewable resource but the scouring process does produce chemical and grease-laden effluent which needs to be treated, and the product itself is treated with borate – a non-renewable (mined) resource – to provide resistance to pests, fire and mould.
• Glass wool
  Glass wool insulation is derived from sand which may be plentiful but is not inexhaustible, and while a high percentage of recycled glass is used in the manufacturing of glass wool, some pure sand is also required.  Phenol formaldehyde binders are commonly used in the process and may produce some formaldehyde emissions, while boron may also be used as a flame-retardant and treatment against microbial growth.
• Mineral wools
  Mineral wools are derived from non-renewable rock though some iron-ore, blast-furnace waste (slag) can be used; phenol formaldehyde is also used to bind the fibres and some formaldehyde emissions may occur.
• Cellulose insulation
  Cellulose insulation is most commonly made from recycled scrap paper but typically includes around 20% fire retardants, insect-resistant agents and acrylic binders – borates commonly, which can leach from the paper when wet.
• Polymer-based insulants
  Polymer-based insulants (polyester, polystyrene, polyisocyanate and polyurethane) are made from fossil fuels but can include high proportions of recycled materials, and some of the products themselves can be recycled at end-of-life. Polystyrene, polyisocyanate and polyurethane are available as both sprayed foam or foam boards and the spraying process does present some issues. Chlorofluorocarbon (CFC) blowing agents, which damaged the ozone layer, were replaced by hydrochlorofluorocarbons (HCFCs) which have significantly lower ozone depletion properties but do have a very high global warming potential (GWP).  Two major replacement options are being considered.

The potential impacts of insulation materials can be reduced by promoting the use of recycled raw materials, and restricting the use of certain hazardous substances such as formaldehyde binders would further reduce the issues arising from the manufacturing processes.

Other challenges for insulation products are the importance of proper installation and thus the need for good training and packaging information.  Home insulation schemes in both Australia and New Zealand have been helpful in raising the level and quality of insulation and some manufacturers also do spot checks to ensure the quality of installation is high.

With some of the materials used in insulation being mined, the specification requires evidence of mine remediation or reinstatement of the natural area at the end of the mine’s life.

The Standards

As well as considering the environmental impacts of insulation products the Eco Choice specification also requires proof of fitness for purpose. For this we rely on the guiding standard for thermal insulation, the joint Australian/New Zealand standard 4859, while the new noise standards are C423-17 and ISO354.

The specification is strongly supported by the New Zealand Green Building Council (NZGBC) and the Building Research Association of New Zealand (BRANZ).  The NZGBC rating tool awards Eco Choice licensed insulation products Green Star points required by developers for commercial buildings, while BRANZ appraisals of insulation products are recognised by Eco Choice Aotearoa as demonstrating that thermal insulation products are fit for purpose.

Future developments

Future work in the area of Insulation products to improve their environmental impact further, and which Eco Choice is tracking for the next revision of the specification, include

• Investigations into alternative, less harmful chemicals to replace formaldehyde binders or boron additives. Some bio-based binders are emerging in the US and these will be reviewed to determine if they are effective.
• Further investigations into the upstream and downstream process chains involved in the production of insulants, such as mining and polyester production.
• More work into development of “take-back” provisions whereby a company takes used products back at the end of their life, possibly with a view to cleaning and recycling.
• Increased recycled content.
• Investigations into development of a specification for hot-water cylinder wraps.
• Additional training requirements for installers.

The benefits of well-insulated buildings (and thus of the value of a specification for this area) include:

• improved indoor comfort levels
• a reduction in respiratory problems
• warmer internal surfaces
• a reduction in reliance on fossil fuels (which contribute to global warming) for heating
• improved durability of internal finishes
• reduced risk of mildew growth

Environment Choice New Zealand developed the Building Insulants specification to provide reassurance to New Zealanders buying insulation products that the products were environmentally preferable, ie that they met standards around materials sourcing and manufacturing as well as installation and disposal.  Licensing initially covered only thermal (heat) insulation but the coverage has been expanded recently to include acoustic (noise) insulation.

Please click here to view all Eco Choice Building Insulation licensees.