According to the Department of Climate Change, Energy, the Environment and Water (DCCEW), residential buildings are responsible for around 24 per cent of overall electricity use and more than 10% of total carbon emissions in Australia.

As the DCCEW also notes, older homes that were built before building energy standards were introduced, are disproportionately responsible for this high level of emissions. The most effective gains, therefore, relate to new housing.

In line with this, and with the Federal Government’s greenhouse gas reduction ambitions, the relevant authorities have been moved to act.

Specifically, the National Construction Code (NCC 2022) requires new homes to achieve a minimum thermal performance rating to 7 stars (out of 10) under the Nationwide House Energy Rating Scheme (NatHERS). What this means, in layperson’s terms, is that new homes must function with 25% less energy than previously.

“This has had an impact on the performance of insulation – compelling the use of higher performing products in roofs, walls and floors,” says Stephen Smith, Technical Director Asia Pacific at Knauf Insulation.

According to Smith, given that post-COVID, hybrid work has become commonplace and people are spending more time at home, there has also been an increase in building rating certifications requirements which has drawn focus on embodied carbon.

“In Australia, BASIX has required calculation since October 2023 while Greenstar projects also require calculation,” he says, adding that NCC2025 will likely include a mechanism for voluntary disclosure, and industry sources suggest it will be mandatory from 2025.

As energy efficiency requirements have increased, higher performing insulation products have been introduced in the market. These products have higher R-value (which is a measure of a material's resistance to heat transfer) and designs intended to create real environmental impact.

According to Smith, Knauf Insulation’s latest ceiling batts offer the highest thermal performance in the market, at R7 and R8.

“These products are designed overwide to go over the timber frame and knit with the adjacent batt, forming a single continuous layer on insulation in the ceiling,” says Smith. “Hence, they can achieve real performance of R7 and R8 respectively with just one single layer of product.".

Previously, other products in the market would require using double layers of R3.5 or R4.0 to achieve similar results but still have energy loss due to thermal bridging.

As Smith points out, increased awareness and regulations pertaining to carbon emissions, and in particular embodied carbon levels, have led to investments in technology that reduces embodied carbon.

“For Knauf Insulation, this includes increasing the quantity of recycled cullet in our products and investing further in our recycling facility in Townsville,” he says.

“The use of compression packaging has also been a key element for Knauf Insulation to ensure more product gets transported with a lower carbon footprint.”

On top of this, given that the most crucial part of glasswool insulation is its binder, there has been a shift to create binder technology without added formaldehyde.

“Knauf Insulation’s proprietary binder – Ecose Technology, is a plant-based binder with no added formaldehyde and no harmful chemicals, which has led to overall low embodied carbon levels of the products,” says Smith.

The manufacturing process is also an important focus of the company’s sustainability efforts.

“Since 2021 we have reduced the carbon intensity of our production by 67%, all electricity we use is renewable and we have a continuous improvement culture, which constantly aims to improve the efficiency of our equipment,” says Smith.

In addition, the equipment used in the facility is modern and based on lessons learned from around the world in other Knauf factories.

“Our scale means that emissions from manufacturing are shared across many products,” notes Smith. “For smaller manufacturers they still need to operate a furnace but if producing less material are less carbon efficient.”

Changes in implementation

As Liam Thai, National Technical & Specifications Manager at PGF Insulation points out, there has been a change in the ways insulation products are being implemented in wall, ceiling and roof systems.

“With the introduction of thermal bridging requirements [in NCC 2019 for Class 2 applications and in NCC 2022 for Class 1 applications], more focus has been placed on products that are able to help reduce the impact of framing on system thermal performance,” says Thai.

“This has resulted in an expansion in products and systems that are designed to provide a thermal break, either as a thermal break strip or as a continuous insulation barrier.”

According to Thai, there are several types of thermal break strip products on the market. Examples include mineral wool-based options, which are mechanically fixed strips designed to meet non-combustibility requirements for Class 2 applications under NCC 2019; and foam-based adhesive backed thermal break tapes, which are suitable for applications in Class 1 buildings.

Insulation barrier products, on the other hand, feature a layer of continuous insulation added either on the internal or external face of the stud frame. These products feature various materials, including mineral wool (for applications in which non-combustibility is required) and foam (where combustibility is not an issue).

“These technologies are not new however innovations have been introduced to the marketplace to facilitate the installation of these products in newer applications,” says Thai.

Ecowool Wall Batts from PGF Insulation.jpg

Above: Ecowool Wall Batts from PGF Insulation are suitable for all residential applications / Supplied.

Asked about PGF Insulation’s own product offerings, Thai highlights the Ecowool range of foil faced roofing insulation, ceiling batts and wall batts, which are designed to provide thermal and acoustic comfort within residential buildings.

“All Ecowool wall and ceiling batts are non-combustible when tested to AS1530.1, which makes them suitable for all commercial and residential insulation applications,” says Thai, adding that Ecowool includes Sensitouch technology, a binding system that has a softer feel than alternatives.

Incorporating a natural anti-formaldehyde ingredient, the system ensures an end product that is low in the emittance volatile organic compounds (VOCs) and complies with all relevant Green Building Council of Australia (GBCA) requirements.

Acknowledging that, when it comes to sustainability, energy efficiency and carbon abatement are only part of the story, Thai points out the various other environmental credentials of the range.

“PGF Ecowool insulation is certified with a Global GreenTag GreenRate Level A Certification,” says Thai. “This provides 100% of the credit point required for insulation in the GBCA Green Star Australia and NZGBC Green Star accreditation systems.”

In addition, PGF Insulation operates according to an Environmental, Economic, Social and Governance framework.

Comprehensive and established with a particular emphasis on sustainability, this has ensured that Ecowool products are manufactured using more than 80% recycled glass; and seen the company align its energy and emissions management schemes with the United Nations Sustainable Development goals.

According to Thai, initiatives related to this alignment include the adoption of electric vehicles within the company fleet and a transition to solar energy, which has resulted in a reduction of its carbon output by 1,300 tonnes a year.

Above: Pacific Urethanes SPF systems being applied / Supplied.

Ventilation and continuous airflow pathways

In line with NCC 2022 10.8.3, a building code clause which outlines ventilation requirements based on roof design and climate zone, Bradford recently launched a suite of perimeter solutions, including Bradford Gold R3.0 Ceiling Perimeter Batts and Bradford Perimeter Spacer.

The Gold R3.0 Ceiling Perimeter Batt (a high R-value-low profile ceiling batt, pre-cut to 400mm for easy installation) and the Perimeter Spacer (a ribbed edge vent insulation ceiling accessory, manufactured from 30% recycled content) deliver all the performance and sustainability benefits for which the Bradford Gold Hi-Performance Range has become known.

Designed to be used together, the two products limit the risk of insulation compression in residential roofs where, because of factors such a low-pitch design, space tends to be at a premium. By maintaining a 20mm gap at the ceiling perimeter, they ensure ceiling insulation does not come into contact with the underside of the roof cladding or roof sarking.

The creation of this ventilation and continuous airflow pathway into residential roof spaces is intended to ensure effective condensation management and ensure the homes in which the products are installed remain comfortable.In terms of sustainability, Bradford glasswool is manufactured from up to 80% recycled glass content.

According to the company this is derived, depending on availability, from either used beverage containers or waste flat glass, while the remaining 20% is made primarily from sand.

In addition to this reliance on recycled materials, which effectively diverts 25,000 to 30,000 tonnes of glass from landfill annually, Bradford Ceiling Perimeter Batts are designed to last the building’s lifetime. Then at end-of-life they, themselves, are suitable for recovery and recycling.

Offering products that are designed for long-lasting performance, Bradford also strives for innovation in its approach to partnerships and research and development. In this way, the company can ensure exceptional product performance.

Choosing Bradford products is not only a cost-effective way to reduce carbon footprints, but a way to ensure residential buildings continue to experience improved thermal performance, acoustic control and moisture management for many years to come.

According to a report by the Australian Climate Council, by adding insulation and fixing drafts, Australian households across different capital cities can save between $354 and $1,561 annually on their energy bills.

Beyond these cost benefits, improved insulation, and the installation of products like those available from Bradford helps lowers greenhouse gas emissions, contributing to sustainability targets and reduce environmental impact across the broader community.

Spray polyurethane foam insulation

One of the important innovations in the market right now is the rapid global adoption of spray polyurethane foam (SPF) insulation, which can create a continuous thermal envelope, eliminate air leakage, and strengthen long-term building durability.

These capabilities align strongly with the above-mentioned NCC 2022 updates, which apart from the 7-Star energy ratings, also require tighter building envelopes, improved thermal performance and better condensation management. Indeed, the NCC Condensation Handbook highlights closed-cell SPF use as “the Clever wall”.

The SPF systems used in Australia, powered by Huntsman Building Solutions technology, and supplied locally through Pacific Urethanes, reflect this move toward higher performing, integrated insulation solutions that support modern building requirements and long-term energy efficiency goals.

Unlike traditional insulation materials that only provide thermal resistance, SPF integrates incredibly good insulation, air sealing and moisture control in a single solution, which fundamentally changes how a building performs over its entire life. Huntsman Building Solutions’ SPF systems hold CodeMark certification in Australia, ensuring that when installed by trained and certified professionals the system complies with NCC 2022 performance and installation requirements.

Where conventional batts rely on friction fit and rigid board products depend on mechanical fastening, SPF adheres directly to substrates and expands to fill all gaps, penetrations, and irregular cavities. This eliminates many of the weak points found in traditional systems such as voids, compression, thermal bridging, and uncontrolled air leakage.

A continuous spray foam envelope delivers high thermal R-value performance (with air sealing built in), moisture resistance and vapour control, durability, and dimensional stability, improved structural rigidity, more stable indoor comfort and improved acoustics.

From a sustainability standpoint, the Heatlok product range incorporates recycled PET plastic and bio-based content, reducing reliance on virgin materials and supporting lower embodied carbon outcomes. The use of advanced HFO blowing agent technology further reduces environmental impact compared to legacy HFC systems.

Independent WUFI hygrothermal modelling completed for an Australian project demonstrated no long-term moisture accumulation and extremely low mould risk when SPF was used as part of a compliant building envelope strategy. Traditional insulation cannot achieve this outcome without additional layers or membranes.

Use of closed-cell Heatlok SPF in underfloor retrofits is a great example, where the benefits of a vapour barrier, high R-value and self-supporting insulation layer provide a warm floor and house in winter, a cool floor in summer and eliminate squeaking floorboards.

Together, these features make SPF a fundamentally different category of insulation. It is not simply a higher R-value product, but a multi-function building envelope system that combines thermal control, air control and moisture control in one step.

Main image: Knauf Insulation offers whole of house insulation / Supplied.

Suppliers List

Knauf Insulation

PGF Insulation

CSR Bradford

Pacific Urethanes

Matt McDonald

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