Episode 11

NCC 2022 and Thermally Broken Windows, with Adam Winterbon of VENTORA Group

17 June 2026 · 48 minutes · Part 1 of 2 · Hosted by Brian Haines, Matthew Graham and Andrew Hooper

Summary

Adam Winterbon, National Product Manager at VENTORA Group, joins the team to explain what NCC 2022 did to the Australian window industry — from the inside of a manufacturer that had to build a thermally broken product line from nothing to meet it.

The conversation covers how VENTORA is structured across A&L Windows, Trend, Stegbar and the rest of the group, why the move to seven stars is the most significant change the industry has seen since windows shifted from timber to aluminium, and the engineering response to it: a full thermally broken range designed from scratch, and a hybrid product that puts a thermally broken sash into a standard frame to bridge the price gap.

It also covers the closure of Oceania Glass, Australia's last float glass manufacturer, and what replacing Comfort Plus and SolTech has meant for supply, for ratings, and for the re-education of everyone who had specified those products for years. Along the way: how glass is actually sourced and finished, why WERS has grown from around twenty thousand windows to roughly seventy thousand, and why thermally broken frames only come in four colours.

In this episode

• 0:33How VENTORA, A&L, Trend and Stegbar fit together

• 2:10Adam's route into the industry, from hospitality to product management

• 4:57Why NCC 2022 is the biggest change in thirty or forty years

• 6:13Building a thermally broken range from scratch

• 7:33The hybrid: a thermally broken sash in a standard frame

• 8:56Inline reveals, and why less visible aluminium helps in Victoria

• 10:00Shared services, brand identity and where the group collaborates

• 11:41Where Breezeway and Aneeta fit, and what is rated in WERS

• 13:04The closure of Oceania Glass

• 14:20Replacing Comfort Plus and SolTech, and re-educating the market

• 15:51WERS versioning, retired codes and the software lag

• 17:14How glass is bought: blocks, jumbo sheets and finishing

• 19:19Sourcing new glass types, and why colour matching constrains it

• 21:02The good, better, best hierarchy for heating and cooling climates

• 23:28Why smaller manufacturers without WERS codes are struggling

• 25:02Default windows: the NatHERS set and the WERSlink set

• 27:07Why custom codes usually rate slightly better

• 30:45THERM files, simulation and the AFRC test sizes

• 36:38Why thermally broken frames come in only four colours

• 39:59How Low-E glass is produced (see corrections)

• 44:38Argon fill, and how long it stays there

Key points

Seven stars was the biggest shift since aluminium replaced timber

Adam's assessment is that NCC 2022 is the most significant change in the window industry in thirty or forty years. A standard aluminium frame with single glazing or clear double glazing had been the mainstay for decades, and it simply stopped working in every case. Five stars had been a reasonable change; seven was another level entirely.

Three brands with no thermally broken product, three months before it mattered

The three VENTORA window brands were, as Adam puts it, about the only window brands in the country without a thermally broken product when seven stars arrived. That meant designing a thermally broken range from scratch, at significant cost in tooling and new profiles. He describes starting from the bottom as both a good thing and a bad thing.

The hybrid exists because of a price cliff

There was a substantial performance gap between standard double glazing and fully thermally broken, and an equally substantial price jump. The hybrid puts a thermally broken sash into the standard perimeter frame, on the reasoning that the sash and the openings are where most of the energy movement happens. It required new profiles and tooling, but assembly barely changed and installation did not change at all, because the perimeter frame stayed the same.

Inline reveals do something for performance

A&L has used an inline reveal since around 1986 — no offset, no fin for the reveal to fix to, with the overall aluminium size equal to the overall reveal size. The practical effect is that heat reaching the external aluminium has to pass through timber to get inside, and far less aluminium is visible internally. Adam notes competitors sometimes read that as a lighter or flimsier product, but testing shows the same quantity of aluminium is present — it is simply concealed by the reveal.

Losing Oceania Glass removed two products the market relied on

With Australia's last float glass manufacturer closed, all glass is now imported, the majority through Asia. Comfort Plus and SolTech had been high performing, widely specified and long established in WERS, and there was no like-for-like replacement. Another brand has since picked up the SolTech name, but it is a different product and does not rate the same. A significant part of the work that followed was not sourcing at all — it was re-educating builders and assessors who had been specifying those products for years.

How the glass actually arrives

A&L has bought offshore for a long time, in blocks — twenty pieces of double glazed units, or forty to fifty pieces of single glazed — direct from Chinese suppliers. VENTORA Glass buys jumbo sheets, 2,440 by 4,800, and cuts and toughens them locally, which covers the special and low volume sizes that cannot justify a three month order from overseas. Introducing a new glass type is slower than it looks, because samples have to be checked for colour: Low-E products can come through yellow, brown, green or blue tinged, and anything used as a local replacement has to visually match what is already on the building.

Good, better, best — and two of them

Rather than offer an unmanageable range, VENTORA publishes an upgrade hierarchy: a standard product at the lowest cost and performance, then good, better and best options rising in performance, cost and sometimes lead time. There are two sets — one for heating climates based out of Victoria, one for cooling climates based out of Queensland — with New South Wales and South Australia drawing from either. The constraint on adding exotic high performance glass is volume: a product only one importer brings in cannot be priced competitively, and there is no point passing on two hundred dollars a square metre for glass when the same money buys more insulation.

Default windows are a starting point, not an answer

The team distinguish the older NatHERS default windows from the newer and much larger WERSlink default set. Both are useful for a preliminary assessment when no manufacturer has been nominated, but a real window suite spans several performance buckets across its operating types, where a default sits in one. Swapping defaults for custom WERS codes late in a project usually improves the rating slightly, because the U-values come down, the SHGC values are better resolved and the frame fractions are properly calculated.

Why thermally broken comes in four colours

A thermally broken frame is two pieces of aluminium joined by a polyamide strip, and you cannot powder coat over the polyamide. Both pieces must therefore be coated separately and joined afterwards, which means the stock cannot be held as mill finish and coated to order the way standard profiles are. Holding every colour is unrealistic, and the top four — black, monument, white and surfmist — account for between eighty-five and eighty-nine per cent of sales across all three brands.

Documents referenced

• WERSlinkThe window energy rating database referenced throughout — searchable by manufacturer and product.

• Australian Glass and Window AssociationIndustry peak body, and publisher of the glazing optimisation study discussed in this series.

• National Construction CodeAustralian Building Codes Board — the code itself, and the Housing Provisions referenced throughout.

Transcript

Lightly edited for readability. Hesitations and repetition have been removed and technical terms corrected; the substance is unchanged. Corrections to statements made on air are marked where they occur.

0:05Welcome to The Rating Room, the podcast where we unpack everything NatHERS. I am Brian Haines, and alongside me are my co-hosts Matthew Graham and Andrew Hooper. We dive into the technical, the practical and sometimes the controversial side of residential energy efficiency assessments in Australia. If you are working in the field of NatHERS, or just trying to navigate the space, this is where the ratings get real. Today we have a special guest — Adam Winterbon from VENTORA.

0:41VENTORA is the parent company. It is the old Australasian arm of Jeld-Wen — a few years ago Jeld-Wen International sold off their Australasian arm and we had to rebrand. Under that branding there are seven or eight companies: three window companies in A&L Windows, Trend Windows and Doors, and Stegbar. We also have Stegbar shower screens and wardrobes, Aneeta Sashless Windows, Breezway Louvres, Corinthian Doors, Regency shower screens, and VENTORA Glass, our own glass finishing plant.

1:26As National Product Manager, I describe the role as a facilitator. I help with all new product development, product improvements, pricing changes, getting market feedback — anything that helps the group or an individual brand improve in their space.

2:10I worked hospitality for more than ten years after high school. I went and got a hotel management degree and worked in hotels and restaurants, then decided in 2008 that I wanted a real job and to stop working weekends and nights. My mother-in-law was working at A&L Windows and got me an interview, and I started as an estimator doing takeoffs for windows and doors. From there I moved into sales as a rep on the road, then internal customer service manager in Queensland, then helped run the project to change our quoting system over to SAP. After that there was no role for me, so we created the National Product Manager role for A&L — the only brand under VENTORA that did not have a product manager. I did that for four years, until my boss went to VENTORA to oversee all three window brands and needed a product manager to help her. That was just over twelve months ago. Eighteen years at the end of this year.

4:57NCC 2022 is one of the most significant changes in the last thirty or forty years — ever since windows went from predominantly timber to aluminium. Five star was a reasonable change when it came through, and now seven is just another level. A standard aluminium frame with single glazing, or clear double glazing, was not going to work in all instances any more. Those had been the mainstays in aluminium windows and doors for a very long time, so we had to move with the times and catch up to competitors and to other countries doing seven star and triple glazing.

5:57What is interesting is that the three window brands under VENTORA were about the only window brands in the country that did not have a thermally broken product when seven star came out. We had to start from the bottom, which was a good thing and a bad thing at the time. And the market downturns are the ones we really struggle with — trying to get a bigger piece of a smaller pie, especially with new competitors entering.

6:13So there was a highly significant project to develop and design a thermally broken range, which we had to do at significant cost. A lot of tools, a lot of new profiles.

7:33Then the hybrid. My boss had a brainwave. We had a fair gap between standard double glazing and thermally broken with regard to performance, so if you could not get there with double glazing and Low-E glass and needed to jump to thermally broken, there was a significant price increase. She wanted us to investigate putting a hybrid product into the market — a thermally broken sash in our standard frame. As you know, the sash and the openings on windows and doors are where most of the energy loss and gain happens, so that gave us a significant boost. There were more profiles to design and source and tool, but thankfully it did not change much in our assembly process, and none of the installation changed because the perimeter frame remained the same.

8:38For anyone listening, the hybrid means the fixed frame is standard but the movable sash is thermally broken. Correct — although it is not really a standard frame, it is an inline reveal frame. A&L has been inline since about 1986, which means there is no offset, no fin for the reveal to be tacked onto. The overall aluminium size is the overall reveal size.

8:56In Victoria that actually helps with performance, because any heat that hits the outside aluminium has to transfer through timber to get to the inside of the house, and there is a lot less visible aluminium. The full thermally broken product designed for all three brands is inline reveal as well, though Trend and Stegbar still have their historical offset reveal frames.

10:00How much collaboration is there between the three brands when you are developing? It depends on the project. We still want each brand to have its own identity — they have their own rich history and their own target markets — but we also need to leverage the commonalities. VENTORA has a number of shared services across all brands: research, development and engineering, finance, human resources, IT. Minor improvements are kept in-house at each brand. Anything major, where we can leverage the group and streamline, we do — and we have taken learnings from all the brands and shared them, so we are trying to lift everybody up.

11:41Where do Breezway and Aneeta fit? Breezway has its own perimeter frame and can provide a full window suite. Aneeta does not — Aneeta has to put their sashless products into a perimeter frame, whether that is A&L, Trend, Stegbar or anybody else in the market. They are open for business: if you can supply a perimeter frame without glass that has a flat edge, Aneeta can put their sashless products into it.

12:32As far as testing goes, I do not believe there are any Aneeta sashless products tested in WERS, though I could be wrong — I have not checked for a while. The louvre products in WERS would have been tested inside the frame, so an A&L louvre is tested inside the A&L louvre frame that their components have been put into.

Correction

Aneeta frames are in WERS. A viewer has since confirmed that Aneeta has frames with current make-ups listed in the database.

13:04Can I follow up on the question about challenges? One that came to mind is the closure of Oceania Glass — one of Australia's last float glass manufacturers, a major supplier of float and laminated glass, with a rich history. Has that affected your industry?

13:37It has. They were the last glass manufacturer in Australia, so now everything gets imported from overseas, the majority through Asia. Oceania had a couple of really long-standing, high quality products in Comfort Plus and SolTech. It was quite a challenge to replace those, because they were very high performing and very well known. Comfort Plus was a laminate which was widely used, so we had to source replacements from overseas — a lot of our brands had overseas sourcing anyway, but replacing those particular products was difficult.

14:20Then we had to educate the market. Builders and energy raters who had been specifying Comfort Plus for a long time, because it had great performance and had been in WERS forever — we had to run an education campaign and say it is no longer available, it does not exist. There was no like-for-like replacement. There are brands in the market now that picked up the SolTech name, but it is a different product and it does not rate the same. So having to re-educate energy raters, builders and the market at large was a significant piece of work.

15:07Have all the products where the glass is no longer available been reassessed with a substitute? They should have been. In a lot of instances we definitely got that done — if we were changing the glass from what was specified because it was no longer available, we would ask for a report to be redone. Unfortunately builders do not like doing that, so in certain instances we could find workarounds. If the report was already at 7.8 stars, we knew a minor drop in performance was not going to bring it below seven, as long as the heating and cooling loads were not affected too much.

15:51This is one of the advantages of WERS: before, products were not really versioned. They could be retired, but they were still used. Now there is the ability to version, update and revise them — albeit with different WERS codes than you had before, so it is more of a moving feast.

16:15WERS has been hammered in the last three or four years, especially with an enormous number of new codes going in. Their backlog was extensive at one point, though they worked through it well. Part of the issue is that new codes were delayed getting into the software, and the NatHERS library was not necessarily updated and transferred over. By the same token, old codes in the software were never deleted by a lot of companies either — they are still kicking around and can still be used, even though the glass has been unavailable for twelve months. I think we all appreciate that we now have access to around seventy thousand windows, where a little while ago it was just over twenty thousand.

17:14Where does VENTORA Glass fit? A&L has had a long-standing offshore purchasing model, buying glass in blocks — twenty pieces of double glazed, or forty or fifty pieces of single glazed, directly from Chinese suppliers. That was low cost, high quality product; even in the double glazing, the quality of units out of Asia from A&L's supplier is very high. VENTORA Glass, the finishing plant, has had a number of different sources over the years, and has leveraged some of A&L's buying power and relationships — but they buy more in jumbo sheets, 2,440 by 4,800, then cut them to size and toughen them where required.

18:24It is very impressive to visit the VENTORA Glass plant and see some of this glass. The sizes are phenomenal, and they do a great job of finishing and supplying the lower usage sizes that we do not have enough volume to store from overseas. An order from overseas takes about three months, so if we need special or low volume sizes we get those from VENTORA Glass stock.

19:19Are there other glass manufacturers or products you would like to see come into Australia? It is interesting. The Chinese suppliers have a unique way of looking at it — they do not really want to sell single glazing, and Australia is not a big market for them, so they would much prefer to sell double glazing. They are pushing us that way, which we do not need in Queensland and parts of New South Wales.

19:50They have a number of different glass types. Every time we ask A&L's main supplier for something, we give them a U-value and a solar heat gain for the glass only, and they come back with a range of options. Then we get samples to see what colouration or shading they have — with Low-E glass they can be yellow, brown, green or blue tinged. We need to make sure that if we are offshoring glass and need a local replacement, they look the same. It is a fairly detailed process, and a lot of the other Chinese suppliers do not have their products rated on the International Glazing Database, so we have had to request ratings, which take a long time.

20:47You can also have too many products. Narrowing it down is a good option — the builders often do not know what they want, and if energy raters have a hundred different options it becomes problematic.

21:02So VENTORA took the view of providing an upgrade hierarchy. We provide our standard product, which is lowest cost and lowest performance, and then a range of good, better and best options. They increase in performance but also in cost, and potentially lead time if we are sourcing double coat Low-E glass. That has worked very well and a lot of the builders have really run with it.

22:07You were the first to put together that good, better, best scenario with all the WERS codes attached, and proxy codes when the software did not have access to the window library. That was a good eighteen months before anyone else was doing that work.

22:43We found we needed to do it for our own sanity. We did a big voice of customer program well before NCC 2022 went live — went to all our builders and asked what they needed and what they thought would happen. Across the board they said they had no idea. So we took it on ourselves to put something on paper we could offer them. They did not know then, they did not know when they would know, and the software was not available. We had to do it, otherwise we would have been sitting there twiddling our thumbs with no direction.

23:28It often surprises me how some window manufacturers, generally the smaller ones, do not have their windows tested in WERS, do not have product codes and cannot give the specification. It does my head in how they still compete in an industry where everything is so specified now.

23:51It is not ideal. You do not have to have your windows rated into WERS, but you should understand your performance — with seven stars and going forward you will not sell a lot if you do not know what products rate to, and energy raters cannot use them in software. Unfortunately the smaller shops and distributors of the past have had tough times: they cannot afford the thousands of dollars for testing that bigger companies can.

24:25We should clarify for listeners that the National Construction Code still calls up that windows be assessed to the AFRC standard, and I believe also checked by another AFRC simulation lab. They do not need to make their way into WERS, but they still need to be assessed to the same standard. Yes, they do. To incorporate that into NatHERS you would have to use default windows — close to what they were assessed at, but not the same as a rated window.

25:02The default window ratings in WERS are interesting. We are still seeing some come through on energy reports, which are not ideal, because we generally get one rating for the whole house — and windows and doors do not work that way. They all seal differently.

25:34We should clarify which default windows we are referring to. There are the NatHERS default windows, the older ones you may still see, and there are also the WERSlink default windows. The original NatHERS defaults were fairly limited; there are a lot more now. And we have seen both over the journey. The newer ones are better, but they are still difficult for us because they are not identical to any of the window brands. So we prefer to go back to energy raters and builders and say, if we are your sole supplier, can you use Trend, Stegbar or A&L codes.

26:41The problem with using the defaults is that they are effectively one bucket, and when you look across a manufacturer's suite of windows, including all their operating types, they do not sit in one bucket — they span two or three or more. Quite frustrating to quote on.

27:07The most likely explanation is that the energy rater never got the information about which manufacturer the builder was using, and defaulted. That is fine for a preliminary assessment — if the client has not suggested a preferred manufacturer and you want to get it in the ballpark, the WERSlink defaults are a good place to start. Then as the project progresses and the manufacturer is nominated, you swap those out for custom WERS codes.

27:59And when you use the custom codes the rating usually gets slightly better, because the U-values are a little lower, the SHGC values are dialled in, and the frame fractions are properly calculated rather than estimated as they are in the defaults. You also get more control over the glass selection — Australia is a vast country with a lot of climate zones, and you are not going to be selling double glazing into Queensland.

29:33We have had a number of goes at getting the right glass in all the climate zones. Essentially we have two sets of good, better, best: one for a heating climate based out of Victoria, one for a cooling climate based out of Queensland. New South Wales and South Australia can take anything out of those two, so it is up to the energy rater which glass type will work.

30:04One of the problems with adding new glass types is volume. If A&L or Trend went to China and found a new glass type that outrated everybody, and we were the only one importing it, it would not be cost competitive. We need significant volume coming into the country as a whole to make it viable. You cannot pass on two hundred dollars a square metre for glass, even with great performance, because you are not going to save that on your insulation or your waffle pod.

30:45Can you explain how testing and simulation works for your products? When we have a new glass type and know it will take a long time to get into WERS, we send it to a company that sends us back the THERM files, which contain a lot of information plus the U-value and the SHGC at the bottom. A couple of months later, when we get them WERS rated, sometimes those values are identical and sometimes the SHGC is out by a little, and we have to redo our materials.

31:47You are not doing this internally? We have a couple of people who have been through energy rating courses, so we have some resources to do it internally, but before NCC 2022 the AFRC simulation work was never a high priority. It takes a specialised company, and unless we outsourced it that person would need another day job, so it would be hard to juggle the workload. We have left it outsourced for that reason.

Correction

VENTORA does have in-house trained and experienced AFRC simulators.

32:40Are they still doing their calculations on a small window? The frame fraction plays a role in those calculations, and the sizes are not indicative of most products we would see on a project — which is where frame fractions come into play. If it is simulated with a frame of one size but what we see on jobs is much bigger, there is more glass involved and less frame, so the ratings may not be quite in line with reality.

34:04The AFRC sizes are: single awning 600 by 1,500. Dual awning 1,200 by 1,500. Casement 1,500 by 600, and the double casement 1,500 by 1,200. Sliding window 1,500 by 1,800.

Correction

The door dimensions were not resolved during the discussion. The sizes modelled in AFRC simulations are2,000 mm high by 1,000 mm wide for hinged doors, and2,000 mm by 2,000 mm for double doors.

34:38Does the inline reveal help with the frame fraction? I do not think it necessarily helps the frame fraction. A lot of our competitors will say A&L windows are lightweight and flimsy — we have done tests and know there is just as much aluminium, it simply looks different because you cannot see it from the inside. How that interacts with heat transfer is better, because you do not get that transfer through the timber reveal. There are also a number of ways we can set the reveals up so you can plaster into them and reduce the visible aluminium further, and that is not limited by whether the sash opens.

36:38Why has A&L limited the thermally broken windows to four colours? That was a tough one. Thermally broken aluminium is two pieces of aluminium zipped together by a polyamide strip, and it is not recommended that you powder coat over that strip. So you powder coat both aluminium pieces individually and then zip them together afterwards.

37:26Because of that we cannot keep any of it as mill finish. With all our standard profiles we keep a range of mill finish, and when a black or green or pink order comes in we send it to the powder coater. We cannot do that with thermally broken, so we have to keep it all in stock on hand — and keeping all eight of A&L's standard colours in stock is unrealistic, when the top four make up between eighty-five and eighty-nine per cent of all sales across all three brands. Those are black, monument, white and surfmist. The rest is a very long tail.

38:30Does anyone still go for anodised or bronze? Yes, though none of the major brands do a lot of volume. There is still a renovation and refurbishment market that needs a little of it, so there are players who do it, but it is not significant volume. Same as some of the old glass types — the old bronze glass you saw a lot in the seventies has died a slow death as well, though you still get a bit of it in commercial: the blues, the bronzes, the super greys. Super green is one of the best performing non-Low-E glasses out there, with a very low SHGC.

39:59Another question we commonly get is how Low-E is produced. Low-E stands for low emissivity, and it is essentially a silver oxide coating on the glass. You can have either a single or a double coating on a single piece of glass. Depending on which surface you put it on, especially in a double glazed unit, it will either stop heat entering the house or stop heat leaving it.

Correction

Low-E is not a single type of coating, and not all Low-E contains silver. There are two families.Soft coatLow-E is sputtered onto the glass after manufacture and does contain silver — in single, double, triple or quadruple silver layer constructions, which is broadly how performance tiers are distinguished.Hard coat, or pyrolytic, Low-E is applied to the glass while it is still hot on the float line and is a tin oxide coating containing no silver. The distinction matters practically, because soft coats must sit inside a sealed cavity, while hard coats are durable enough to be used on a single glazed pane.

40:37So if you are in Queensland and you have it on the inside of the house, it will stop heat getting in, and if you have used artificial cooling it will stop that cool air transferring out. And the opposite in heating climates: it will stop heat that you have artificially generated inside the house from getting out.

41:11Do you think there is enough education in the industry about coatings and their surfaces? I can never remember whether it should be on two or three for Melbourne. In short, no. We did an extensive education piece through VENTORA in all three brands, though some builders just do not care — they have enough to worry about and leave it to us, the energy raters and the window suppliers.

41:55In Victoria or heating climates with double glazing, you want it on surface two, which is inside the double glazing on the outside pane. And if you are putting a second coating on, it is on surface four, which is inside the house.

Correction

This has the heating and cooling configurations the wrong way round.

In a heating dominated climate — Victoria, Tasmania, the ACT, the cooler parts of New South Wales — a high solar gain Low-E belongs onsurface 3, the cavity side of the inner pane. That keeps the low U-value while allowing more winter sun to pass through, which is exactly what a heating dominated dwelling wants. Placing the coating on surface 2 instead reflects a portion of the solar energy before it enters the cavity, which pulls the solar heat gain coefficient down — useful in a cooling climate, counterproductive in a heating one.

The reverse applies in cooling dominated climates, where a solar control Low-E onsurface 2is the appropriate specification, blocking solar heat before it reaches the room.

A note on the second coating: the configuration described here, with coatings on surfaces 2 and 4, does improve the U-value, but a coating on surface 4 sits exposed to the room and is not recommended.

For a NatHERS assessment none of this changes the method, because the assessment uses the rated U-value and SHGC published in WERS and the surface placement is one of the manufacturing decisions that produced those numbers. It matters at specification stage, for whoever is choosing the glass.

42:14Those coatings are a coating, so we have to be careful when they are on the inside of the house, whether that is single glazing in Queensland or double in Victoria. We did a big education piece with cleaners — no sharp objects, which you should not use on glass anyway, and rings. We have had house lots over the years where we had to replace all the glass because the cleaners scratched it, and it is not something you can fix. The glass has to be replaced.

43:03Is it easy to tell from the way glass is described in WERSlink where the coating is? That is part of the problem. It is good for energy raters to know, because it makes the difference between what you choose for a heating dominated client and a cooling dominated one. And if you were putting a double glazed unit with Low-E into Queensland, you would specify the coating on a different surface, so we would need to tell our suppliers which surface it goes on when they manufacture the unit.

Correction

The coating surface can be identified from a WERS listing. Opening the long description of the glass make-up shows the construction read from outer pane to inner, and where a double glazed unit carries two Low-E coatings the surfaces are identified within that description.

44:22Adam, can you cover what surfaces one, two, three and four are? The double glazed unit has two pieces of glass. The outside piece has surface one on the outside of the house, exposed to the elements. Surface two is inside the unit on the outside pane. Surface three is inside the unit on the inside pane. And surface four is inside the house — so cleaning from the inside, it is critical that it is looked after.

45:16Most of the double glazed units sold in Australia, and all of the ones by VENTORA, are argon filled, an inert gas which also helps stop heat transfer.

45:31Do we know how long the argon stays in the unit? We have been told at least ten years. At OzFenex last year there was a speaker selling handheld machinery that could tell you the percentage of argon still in there — the full version was sixty or seventy thousand dollars, with a smaller handheld version available. It begs the question: after ten years, if there is no argon left, how much performance is lost? Some of the old A&L codes in WERS have both an argon and a non-argon version, so it could be recalculated.