triple glazing

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Why our 9+ Star Superpod® House Barely Reaches 7 NatHERS Stars

2D South Elevation Drawing

Why our 9+ Star Superpod® House Barely Reaches 7 NatHERS Stars.

This is the street frontage of an old house, showing a Superpod® house extension going up soon (peeking out from behind) in an old established part of Melbourne, Victoria, Australia. The house at the front is very old. In fact, the houses in this street are 130 years old.

The Superpod® house extension at the back is over 200 sqm with 2 storeys, 3 bedrooms, 3 bathrooms, kitchen, dining, and 2 lounges. You won’t see it much from the street. It’s the shaded orange part in this image.

The extension, if it was rated under the NatHERs energy rating scheme, would be a 9 star house.

Sounds good, but we think it’s better than that. That’s because the NatHERS scheme doesn’t fully recognise all the benefits of our certifiable passive house system. Like the performance of our fully imported windows. Or our thermal breaks. Or our airtightness.

Check out one of our previous stories on this: NatHERs star rating doesn’t test airtightness

But, alas, we can barely reach 7 stars with this whole building. That is, taking into account the old house together with the super performing extension. Retrofitting the old 1890’s house at the front isn’t going to make it easy. It faces south. It’s got single glazed windows. And insulating the poor old walls will be a trick.

But let’s focus on the good part. We are facing climate change head on. We are providing optimum comfort and health. We are loosening the hold of the ever growing power bill. All this without solar panels. It’s the good building that counts. Jewellery on the roof doesn’t replace decent clothing in the fabric of the building.

PS Our Superpod® system is a fast, easy way to achieve the world’s best practice for energy efficiency and comfort. The International Passive House Standard. Our patent pending system (United States next, here we come!) is available for licence to designers, developers and builders. From tiny pods to high rise and commercial buildings.

I know, it’s hard to get your head around. Licensing a building system? After years of developing our IP we think it’s worth it. Innovation is often hard to get your head around. We look forward to co-innovators who want to work with us!

2D South Elevation Drawing
2D South Elevation Drawing
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A Certified Passive House – Why Bother?

Passive House

Without a certificate, it’s just a passive house. Or is it?

I was pleased to be informed that I have been invited for the second time to present on this topic at the International Passive House Conference.  This one is in Munich, 2018.

Below is the abstract I submitted.


“Certificates are sometimes treated as a unnecessary label, and other times like a necessary evil. They can be ignored as irrelevant; or resented and feared as a barrier to entry.

The Passive House Standard requires certificates. Sometimes for building components. Other times for designers. At all times for the building itself. The physical building as built and tested.

This list of certificates makes it more difficult to achieve the Standard.

But, after all, it is a standard. It is not just a warm and fuzzy feeling (although it is that and much more).

Certificates for components can be hard to obtain. And certified components are not yet imported around the world.
Certificates for designers are hard to obtain. And certified designers can be thin on the ground in your country, let alone designers who have actually designed a certified passive house. Newly qualified designers do not have “runs on the board”.

And certificates for buildings are hard to obtain too. The process is so rigorous and laborious, from design stage to building stage to completion and testing. You can do everything well until the end, and fail the blower door test. What a disappointment that can be for all involved.

Because the certificates are hard to obtain, people find ways of dismissing their relevance. They can see the benefits of the Passive House Standard, but they can’t obtain them. So they start to appropriate the terminology of the International Passive House Institute and claim that their inferior buildings are equivalent. They call their buildings “passive house” buildings. And members of the public do not know the difference.

In some countries like Australia, this is complicated by the fact that solar panels are easy to instal. So people claim their houses are “net zero” ie better than passive, simply by adding a few solar panels to the roof. The customer may end up paying no power bills, so they are relatively happy, not knowing that the Passive House Standard could have produced so much more.  Because of ignorance in this field, and salespeople who are keen to sell their products and services, the benefits of potential certification are lost.

Sometimes people think that they can tack on or add on a certificate to a good quality building. But the road to certification is long and paved with obstructions. Without a certification aim, their design, insulation, connection details, windows, and ventilation will be sub-standard.

A certificate for a passive house building is not just a ticket. It is the result of a complex, rigorous process with commitment from all involved.

Certification makes a massive difference to the end product, the comfort for users, the existence of drafts, condensation and mould, and the power consumption.

For those who understand the Passive House Standard, we need to explain to consumers what it means. Perhaps explaining it will help people to choose true Passive House, instead of a poor alternative.”

With the Superpod® system, we aim for certification every time.  We are not content to stop when architectural lines are on a page.  We are content when the building is finished, tested, and certified.

What do you think?

Do you think solar panels and timber linings make a building sustainable?

Do you think any building with passive house elements can be called a Passive House?

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Australian High Rise Buildings Should Cut Glazing by at Least 50%

Melb CBD

Australian high rise buildings are inefficient.  They do not run efficiently.  They are not comfortable enough.  They waste energy.  They contribute to climate change.

The latest, state-of-the-art high rise office buildings I have visited, get too hot and too cold.  In one room you try to work, stifling in the Western sun. There’s no relief except for airconditioning, which is too cold and too erratic. The next room is cold as it faces South.  You are uncomfortable standing or sitting next to the glass in either room for much of the year.

A key reason for all of these problems is the amount of glazing on our high rise facades.  It’s excessive.  It’s wasteful.  It makes little sense.

But it’s cheap.

Perhaps the designers will tell you that people want it, and the builders will tell you that people will want it.

But do people really want all that discomfort?

It’s doubtful.

Do people really think pure glass facades are so beautiful?

It’s not likely that people are so wedded to how the building looks from the outside as they stand on the street looking up to the 20th floor.  How often do they look up to the full height of the façade from the ground down below?

In any event, is glass so beautiful?  Is it that much more beautiful than solid materials?

More important that a perception of aesthetic beauty from a vantage point nobody will ever use, is the true beauty of living well in a space, and the beauty that comes from designing well for human occupation.  If we redefined beauty in this way, (ie good design), would we allow our building codes to enable such inefficient buildings?

Compare our high rise buildings with the Cornell Tech Building in New York.  This 26 storey 350 unit residential building on Roosevelt Island on the East River, is the largest Passive House-certified structure in the world.

And it was built to a tight budget.

Projects like this are inspirational.  With a fast-built wall panel system, making airtightness simpler (similar to the concept we have devised for our passive house facades under the Superpod® banner), the building has a modernist appearance, with white solid bands around the glass.  The glass is not floor to ceiling, but is enough to enable spectacular views for the occupants.

The glazing makes up only 23% of the beautiful façade.

And the beauty of this building is not merely aesthetic.  It is “deeply” designed, with great attention to materials and details that you will never see.

Of course, part of the attention to detail is the actual quality of window.  The glazing is not cheap single glazing in a certified passive house building.  Rather, it will be triple glazing, or sometimes double glazing, with very thermally efficient frames.

All this is done to achieve a beautiful living environment, with comfortable temperatures, fresh air, and a power consumption a mere fraction of what is standard in Western countries.

One of the consultants on the New York Cornell project, Lois Arena, mechanical engineer, has been a key member of the team.  I was fortunate to meet her and hear her speak at the New York Passive House High Rise Symposium in New York a couple of years ago.  It is clear that it takes dedicated, committed leaders like Lois to achieve a certified passive house of any size, let alone the largest one in the world.

And the true beauty of Cornell would not have been possible if a key member of the design team had insisted on a fully glazed building.

Similarly, the architects’ involvement and support was integral as it is in any passive house project. An interview of Blake Middleton, architect, published by “the Architects Newspaper” on 3 April 2017, reports that while the client was enthused about Passive House after a trip to Europe, the development team were initially unsure if they could achieve the Passive House Standard.  Blake said: “Once deeper into the research and design process, and more familiar with what was required, all involved became more confident we could make this work. Everyone stepped up to commit to the effort.”

We can do better in Australia.

The high rise buildings I have occupied or visited in Melbourne in recent years have been unacceptable.  When you work in an office, you don’t think about how the façade looks from the ground.  You think about how cold you are when the sun goes down and the warmth in the room is sucked out of the glass.  You think about how hot you are when the westerly afternoon sun shines through all that glass unabated.

And during those times, when you ask the building manager to adjust the aircon, or you put back on your suit jacket, or you wish you could be wearing a t-shirt – do you really think about the fantastic views from all that floor to ceiling glass all around the building?

Again, part of the problem is the poor quality of our glazing in this country. We should at the very least be using double or triple glazed windows to bring a more comfortable living environment into our buildings.

The Passive House Standard is relevant in Australia, and every time you feel discomfort in your building, remember that the designers could have done better.  And our building codes could be improved.  And we could all step up to commit to a better Standard.

Not just aspirational components here and there.  Not just passive house principles.  But true blue, properly designed and constructed certified Passive House Standard buildings.

We need to let go of our obsession with architectural renders of high rise buildings covered in cheap, shiny glass.

Designing properly, to achieve the energy-efficiency and comfort of the Passive House Standard is possible.  And it’s relevant.  And it’s what true beauty in buildings should really be about.

When you’ve experienced a passive house building in any of our Australian climates, as I’ve had the privilege to do in a Superpod® podhouse®, you know it’s both relevant and possible in this country.

As it is in Frankfurt, and London, and New York.


© Fiona McKenzie, Superpod Pty Ltd

25 July 2017

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What’s Going On With U Values?

U Values

Have you been wondering how U values for windows are calculated, and why different suppliers and different countries seem to use different numbers?

We’ll begin slowly, as getting a handle on the fundamentals is critical.

What is a U value?

“U-values measure how effective a material is as a thermal insulator. The lower the U-value is, the better the material is as a heat insulator” (

Hence, a “U-value measures how well a product prevents heat from escaping. It is a measure of the rate of non solar heat loss or gain through a material or assembly. The lower the U-value, the greater a window’s resistance to heat flow and the better its insulating value.” (

“The U-factor or U-value, is the overall heat transfer coefficient that describes how well a building element conducts heat or the rate of transfer of heat (in watts) through one square metre of a structure divided by the difference in temperature across the structure… a smaller U-factor is better at reducing heat transfer…A low U-value usually indicates high levels of insulation. “   (Wikipedia)

Also, a U value is the opposite of an R value.  The R value measures thermal resistance of an element as opposed to its conductivity.  Hence, an element’s R value is simply 1/U, and conversely, U = 1/R.  It therefore follows that higher R values are better thermal performers – just the opposite of the U value scenario.

That’s a bit confusing in Australia, because we use U values for windows, and R values for walls and roofs and floors (if you are including insulation in the floor, which in the colder parts of our country, you really should be doing).

In Europe, however, they use U values to describe walls as well as windows.

Furthermore, a U value is different from an SHGC value.  The SHGC (solar heat gain coefficient), or g value measures solar heat gain and is expressed as a percentage.  The higher the percentage, the higher the heat gain through the element.

In hot parts of the world you don’t want a high SHGC – you want a lower one.  But you also want an effective (ie: lower) U value, to stop the heat transferring into the building (and to stop the cool temperatures moving out of the building).

But let’s focus on our our unit of choice for this article, the U value.

A U value must be calculated or assessed for both the window frame as well as the glazing itself.  Because a frame is made of different material from glass: two U values must be determined.  The frames’ U value is often referred to as the Uf value.

The glazing-related value, called the Ug value, relates to the glazing unit part of the window, which includes the glass itself as well as the gaps between the panes (if double or triple glazed) whether they be air or another gas like argon or kryptonite.

Therefore the goal is to combine the two separate U values (the Uf and the Ug) to determine the U value for the entire window as a whole (ie: Uw).

Frames typically provide higher U values, or worse performance, than glazing, if you are looking at double or triple glazing.  That means that if you have a small window to calculate, with a Ug of .6, the small window will come out with a worse Uw rating (higher U value) than a large window – simply because the small window has more frame in proportion to the glass.

Why is this such an important point to note? Simply because it makes one aware that there is no such thing as a standard U value for a whole window setup (Uw) regardless of its actual size.  You will always need to calculated a Uw value for the exact size and shape of the window unit as the proportions between frame (Uf) and glass (Ug) will always change depending on the window’s size and configuration.

If you are ordering 10 windows of different sizes, you may end up with 10 different Uw values for your project, even though the exact same glazing and exact same window frame profiles are used throughout.

The next confusing issue is that of measurement units themselves: imperial vs metric.  Australia and Europe follow the metric system.  That means the U value is described as watts per meter squared x kelvin (W/m²K).

That means that a European U value of 1 will convert into Australian language as an Australian U value of 1.

In reality you will discover that most European windows come with lower U values (higher performance) than Australian windows.  That’s because European windows are constructed differently, with different materials.

The imperial measurements are utilised in the U.S, however.  It causes a lot of confusion with the rest of the world.  (Indeed, one green building journalist in the U.S. wrote about our Superpod certified passive house, saying that he could not understand how our building was high performing, because he thought that the insulation was so thin.  I had to point out to him that European U values are not the same as U.S. values – he had simply failed to convert from European to U.S reporting practices for U values, which skewed his perception massively.  Fortunately he could correct his online article quickly!)

A detailed review of the U.S. vs EU standards is found in the paper: International Window Standards, Final Report/April 2014 for the Homeowner Protection Office, branch of BC Housing, by RDH Building Engineering Ltd in Canada.  It is 74 pages long.  It says that “there is no straightforward way to compare North American and European product performance.”  It reviews in great detail the differences between window rating systems in North America, Europe, and for Passive House.

At this stage the mathematics gets quite complicated.  Suffice to say that there is a rule of thumb for converting metric and imperial U values, and that is to divide the metric U value by 5.6783, in order to get the imperial equivalent.  This means that a U value of 1 in the EU will be (roughly) equivalent to a U value of 0.174 in the US – assuming the same testing methodology for that window.

Let’s now consider that last point regarding testing methodologies. There is a voluntary window organisation in Australia called WERS: The Window Energy Rating Scheme.  It is run by the Australian Window Association (AWA).  It is not a government body.  If you are a member of the AWA you can participate in WERS, and you can see WERS ratings for different window companies specified on their website.

The WERS website says that their members must obtain energy ratings for their products from a rating organisation that is accredited by the Australian Fenestration Rating Council (AFRC).  The AFRC is an incorporated entity.  It is not a government body.  The AFRC states on its website that it “will develop, administer and approve the only uniform, independent, comparative rating and labelling system for the energy performance of windows…”

In a similar way, European made windows must be tested against European standards.  For a certified passive house, your windows must be accompanied with a certificate to the EN Standard.  EN Standards are documents that have been ratified by a European Standardisation Organisation for the purposes of EU Regulation.  There are also DIN standards in play throughout Germany.  There are literally thousands of EN standards for things as varied as cork floor testing and electromagnetic compatability emissions standards for industrial environments.  The U.S too has its own standards and compliance testing facilities.

As we noted above, most Australian windows have higher U values than European windows, because of the different materials used.  This in turn is partly due to more stringent legal requirements.  Germany, for example, has mandated low U values for some time (generally under Uw 2).

In contrast, according to WERS,

“U-value ratings generally fall between 2.0-10.0 W/m2.K for Australian products.”

But there’s another thing, if a window company says that all their windows have Uw values equal to 3, they are not providing accurate or practically useful information.  As stated earlier, there would be different Uw values depending on the actual size and configuration of each and every window.  Surely this is the only reliable and useful information when considering realistic and practical thermal performance!

Further, if you want your house to be certified as a passive house, the detailed and structured building physics modelling program (ie the Passive House Planning Package) requires proper EN standard compliance regarding U value reporting, and checks the sizes of each window carefully.  Consequently, the Passive House program requires the specific Ug and Uf values to be separately nominated.  If you really want to model the heat loss of any window, you need to calculate the heat loss through that size of glass as well as the size and shape of the frame, to consider the whole effect of that particular window.

Also, U values say nothing about the installation methods (which the Passive House Standard also requires to be nominated and verified), air leakage, quality of production, or tolerances.  How many of us have watched those Grand Designs episodes where the windows are 10mm out?  Your window should fit.  In Australia, our building code tolerances may allow for things that are just not going to cut it if you want the building (and the windows) to actually perform.  So there is much to watch out for.  If we understand what is being reported when numbers, ratios or percentages are being bandied around, we will know better what is being assumed, and what is being accurately calculated.

See published also in  What’s Going on with U Values