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NCC 2022: The 5.19 W/m²K Elephant in the Room

After years being on the periphery of the glazing industry, playing in the design and construction space as opposed to understanding the idiosyncrasies of the local glass and framing supply chain, I found myself speaking at AusFenEx 2019 yesterday afternoon.


Organised by the freshly formed Australian Glass and Window Association (AGWA), an association representing over 1000 member companies from the glass and framing industry, this event is well known for its networking focus.


However, it is also the perfect platform to get under the skin of an industry that is subject to tremendous local challenges and change, as we transition to higher performing building design, driven by recent changes (Commercial - 2019) and future (Residential - 2022) versions of the National Construction Code (NCC).


My focus was trying to tame the beast, change the course of the ship and ultimately encourage the glass and framing industry to appreciate the magnitude of changes on the horizon. In this post, following my last post on ‘NCC 2022: NatHERS in a carbon restrained world?’, I will stick with the residential side of things and continue to raise the question:

Is the NCC a driver for better, energy-efficient windows?

Taking the stage with the title ‘2019: A Year of Change for Australia's Glazing Industry’, my key objective was to:


a) disable the ongoing excuses and ‘she’ll be right’ culture embedded in the glass and framing industry supply chain, and;

b) highlight the ongoing disregarding of future drivers to minimum compliance and make a point that much of the supply chain was not better in quality and performance than 50 years ago!


Throwing my data science hat on, I focused on the numbers associated with two large, publically available datasets. No comment on the accuracy of this data…but it’s great that it is available!


Firstly, to set the scene from a supply chain perspective and to present a position of market availability, I utilised the WERS database for residential buildings. Via this method, I was able to review 24,400 WERS products available to the residential market. While the WERS system has many well-known challenges and I don’t believe it currently holds enough value to justify its position on the market, it is the only system available across Australia.


Next, developed by the CSIRO, I extracted over 98,000 data points from the Construction (Windows) dashboard on the Australian Housing Data portal. Via this dashboard, I was able to look at various climate zones to ascertain what glazing was being installed to meet minimum compliance in Class 1 (Dwelling) and Class 2 (Apartments) residential buildings.


As anyone exposed to the Australian residential construction will confirm, the anecdotal performance quality of glazing is very poor. Typically, the energy rating providers primary goal will be to provide the lowest glazing performance as part of there core service to offer a ‘value managed solution’. This ultimately offsets the need to install better glazing. All depending on your interpretation of 'value' I guess, but it broadly aligns to a dive to the bottom cost-driven exercise, where comfort, ongoing energy costs and GHG emissions are thrown out of the metaphorical window!


Putting aside the race to the bottom while focusing on the numbers in terms of product availability across Australia, we can place products into groupings based on System U-values. I have used ranges up to 5 W/m²K. Anything above 5 W/m²K cannot be aligned to any genuine level of thermal comfort or performance. Based on 24,400 data points, the vast majority of products available today are very low performing and greater than 5 W/m²K. Little more than thermally inefficient, unhealthy, condensation prone water control layers stuck onto your building!


However, its not all complete doom and gloom. We can also see a nice peak in better-performing products between the 3 – 3.5 W/m²K range, which starts to tell part of the story. However, what this data hides is that the average residential supplied product from all suppliers is only 5.19 W/m²K across Australia. Remember my definition above!


What is clear is that something is driving lower-performing products yet there is also a range of better performing products available to the market far better than the average. So, options are available, with over 60% of the residential supply chain being double glazed yet very average performing systems.


But what glazing is being installed to meet the minimum performance requirements of the NCC in residential buildings? To answer this, we need to look at some examples at the State level and the CSIRO data to know what glazing is being adopted on compliance certificates. As certificates are not issued in all States, I will focus on NSW and Victoria below but have much more data available.


First up, NSW. As you will quickly note below, a frankly ridiculous range of non-performance is being used in construction via NatHERS compliance, with nearly all window systems greater than a System U-value of 5 W/m²K in homes. This nicely aligns to the average values from all suppliers, 5.19 W/m²K. Indeed, with typical window systems in the 6 – 7 W/m²K range most common in NSW, even less than the average being supplied to the market, a performance equivalent as high as 16 times the heat loss from a standard wall construction. No polishing these stats!


Apartments fare a little better, with year on year growth in double glazed systems seeing some recent improvements. Using the 2018 dataset, we can state that 90% of homes and 76% of apartments are single glazed in NSW. Is the NCC a driver for better energy-efficient windows? Appears not!


In Victoria, we like to whistle a tune that we do things better. From the data, this appears to be marginally true, but don’t forget that pinch of salt. With a much colder climate and arguable higher thermal requirements than NSW on average, Victorians do tend to adopt higher performance values but let’s not get too excited. With values also typically greater than a System U-value of 5 W/m²K in homes, we can leave the chest-beating until the end of the footie season as we have nothing to shout about here!



Apartments, however, fair considerably better, likely due to construction techniques and procurement strategies adopted by the major contractors building the enormous towers in the Melbourne CBD and the sprawling complexes on its periphery. Again, using the 2018 dataset, we can state that 77% of homes are single glazed while only 30% of apartments are single glazed. Indeed, apartments are well on their way to being in a much better place due to a combination of factors, so it is fair to say that this market will continue to adopt more thermally efficient glazing.


I have many more datasets, but in Australia’s two largest markets, the takeaway is broadly comparable. In homes, largely built by the volume builder market, we are crashing and burning in the value proposition of better glazing. The numbers suggest a combination of factors. Are we educated enough to make a value-driven choice between kitchen and toilet furniture or the ongoing cost or comfort? Are we beaten down by the local ‘premium’ for double glazing by a fabricator or builder not interested in providing better systems? Are the builders ‘value-managing’ this before we even get a choice?


At the end of the day, the unavoidable truth is that the NCC is not a driver for better energy-efficient windows if single glazing is being installed at such a rate. As we move forward into ongoing discussions regarding the virtues of better glazing systems and 2022, we need to reinforce the policing in construction, plug the performance gap and commit to a better average market supply value of 5.19 W/m²K. Realistically, if any commitment to health and energy efficiency is on the agenda, the glazing and framing industry need to know what the target is now, so they can respond to the needs of tomorrow.

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