Considering cost of living pressures, rising energy bills, and the ongoing threat of climate change, residential insulation has never been more important. The good news, as Matthew McDonald writes, is that the products of this type currently on offer have never been more effective.

According to the Department of Climate Change, Energy, the Environment and Water (DCCEW), residential buildings are responsible for around 24% 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.”Using More Recycled Raw Materials to Create Better Products.

Source: Architecture & Design | Sustainable thermal insulation choices