In ‘Sustainable houses’ Category

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ReNew 144 editorial: Time to get smarter

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There’s a lot to weigh up when you’re considering the sustainability of smart homes. As the tech evolves, are we just creating a new e-waste stream, with older devices relegated to junk far sooner than they should be? On the other hand, perhaps we should get excited about the potential for smart devices to run our homes to maximise sustainability: turning off heating when no one’s home, opening windows to access cool air at the right time of the day, or letting us turn off an appliance remotely if it’s been left on by mistake.


Many homes already have some smart tech, from smart TVs, washing machines and dishwashers, through to smart energy monitoring and control systems. Given that, we thought it was a good time to do a general survey of the smart tech area and ask when it could help sustainability. And where can the smart version of a device be better?

We consider gimmick versus potential: we look at smart plugs, solar diverters, and, yes, Google Nest and Apple Homekit. There’s also the well-named If This, Then That, a cloud service for those times when your smart devices don’t play well together.

In a second special feature, we look at efficient electric heating. The ATA’s latest research shows that getting off gas can have both environmental and financial benefits, so we consider the options when shifting from gas to electric heating. Whether you’re looking for the most efficient space heating or wondering whether personal heating could work for you (plug-in seat warmers anyone?), we present the choices and consider the pros and cons. As one of our case studies demonstrates, the more you can do to improve the thermal efficiency of your home, the less you’ll need to spend on heating. So don’t just focus on the heater—think insulation, draught proofing and, when designing a new home, how to make passive solar design work for you.

There’s much more besides. Two urban innovators are growing more food than you’d expect on a backyard block, one as a business and one to feed their family: it’s inspiring to see how they’ve gone about it and just what’s possible.

In our story on the emissions from unconventional gas production, it’s shocking to see the extent that ‘fracking’ has grown over the last few years, with tens of thousands more wells planned. We look at what this means for greenhouse gas emissions from the wells themselves; not a good news story.

We also take a ride on the ‘solarcoaster’, with one person’s experience of solar upgrades over 15 years—next issue, we plan to look at upgrades in more detail for those with older systems. Plus, the good news on electric vehicles is changing so fast that we had to delay our market update submission until the last minute to avoid seeming out of date.

Enjoy and let us know your feedback. Our reader survey is staying open a couple more weeks so there’s still time to give us your input:

Robyn Deed
ReNew Editor

ATA CEO’s Report

As the southern states head into winter, our attention turns to how to keep our homes warm. Here at the ATA, we always advocate for making our buildings more energy-efficient with well-insulated and sealed homes as the first step.

But when looking at active heating systems, ReNew readers will be pleased to see that we have released our full report on Household Fuel Choice in the National Electricity Market. The updated research found households will be between $9000 to $16,000 better off over 10 years if they establish their new home as all-electric with a five kilowatt solar system, rather than gas-electric with no solar.

There is just no reason economically for new homes to be built with both electricity and gas. This has been the case for many years in Australia’s north, but it’s now also clearly the case in colder climates like Victoria and Tasmania. Heat pump hot water and split system air conditioning systems are far more efficient than gas appliances and solar systems are cheaper than ever.

The benefits are not only for the hip-pocket; this approach also ensures that our homes are healthy and adequately warm during the colder months. This is especially important for the elderly and other people at risk due to their homes not being kept at a comfortable temperature.

At the ATA we are proud to be able to conduct and promote our independent research to ensure that we do not invest in new gas infrastructure, which would lock households into higher energy costs and not assist in our pathway to a 100% renewable electricity grid.

You can purchase ReNew 144 from the ATA webshop.

Hue kit

Houses that think

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Smart home technology is touted as the way of the future, helping to make life easier while reducing energy use. But is that really the case? Lance Turner investigates.

In the last few years there has been ever-escalating enthusiasm for internet-connected appliances and devices, in the belief that connecting devices to the rest of the world can make life better for householders. However, there are both pros and cons of making your house smarter, and there are varying degrees of ‘smart’, so what level of automation should you be aiming for?


What is a smart home?
A smart home can be defined as one that contains one or more devices that collect data, store that data, either locally or in the ‘cloud’ (on an online server), and can act on that data to make decisions as to what they should do. The motivation behind adding smart devices is usually to improve comfort levels, safety and security of a home, and may also be to help an occupant with a disability.

Most likely, your home probably already contains at least one smart device, whether you realise it or not. For example, TVs usually have some level of network connectivity and many collect data, or can be programmed to. Other typical smart devices can be seen in List 1.

What are smart devices?
So what exactly makes a device ‘smart’? Firstly, as mentioned, it will need network connectivity. This may be via common wi-fi or wired ethernet, which allow it to connect to your existing home network directly, or it may be via one of a number of other protocols (see List 3). If the device uses one of these other protocols, then it will need to connect to an intermediate device, known as a hub or controller (see List 2). This hub then allows it to connect to the home network, and hence other devices in that network, as well as communicate with the wider internet.

Smart devices are usually also able to collect data and store it, either locally in the network or on a cloud server. They can usually also make decisions based on that data. For example, a smart window opener might close windows if it detects rain.

Smart devices can often also use external data sources to make decisions. For example, a smart irrigation controller, such as the Hydrawise unit, might use weather data from a weather service to decide if it should water the garden or not.

Many smart devices can also communicate with other smart devices in their own home network. For example, a smart smoke alarm, such as the Nest Protect unit, can cause a Nest camera to send you a photo when the alarm is triggered.

Read the full article in ReNew 144.

Image courtesy Condon Scott Architects, Photography Simon Larkin.

A clever little home

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Contrary to many people’s experience, Will Croxford and his wife have found that smart tech has made their house simpler and cheaper to run. He explains the features they use.

You might have seen our tiny house on the cover of the latest issue of Sanctuary (ReNew’s sister magazine on sustainable design). After years of research and planning, we built and then moved in on 1 August 2017. Our house has a footprint of only 30 m2, but it feels well designed and spacious. It is built using SIPs (structural insulated panels) for the floor, walls and roof, and is close to Passive House standard. We also incorporated smart technology which helps reduce our energy bills, light up the house and keep us warm in winter. Contrary to many people’s experience with smart house tech, our life is simpler because of it. This is how we do it.


Aiming for ‘best in class’
One way to get a ‘smart home’ is to purchase a single integrated system. Such systems are usually installed by a professional and are often simple to use and robust. Another way, which is what we opted for, is to use a DIY approach with separate systems and multiple apps. In a DIY system, things aren’t always simple and there may be limited integration between apps.

Even though it’s not as a simple, the DIY approach suited us. I’m a tech person who loves tweaking settings and working with programs that I feel are the best. I like to think of this as a ‘best in class’ approach. For example, our smart lighting is the Philips Hue system because we think it’s the best in class. Obviously some will disagree; maybe ‘best in class’ is better described as ‘best for us’.

A downside with ‘best in class’ is that the many and varied systems used may be proprietary and hard to integrate together. But there are always ways around these problems.

Read the full article in ReNew 144.


A mania for monitoring

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When you build a high-performance house, you want to know that it’s performing as expected. Cameron Munro has monitoring in place to do that—and he’s producing some lovely graphs in the process!

We moved into our renovated home in Melbourne in November 2016, having undertaken an extensive renovation with a focus on massively improving the energy efficiency of the building fabric (for more, see ‘All-electric and hydronic’ in ReNew 141).


Our approach was driven by a desire to produce a comfortable home no matter how hot or cold it was outside and to reduce our operating costs to as close to zero as possible. To do this we used the Passive House approach, a scientific method incorporating extensive modelling and verification. This required very high levels of insulation (including high-performance windows), avoidance of thermal bridges and a building wrap that reduces the air infiltration to about 1/15th that of a normal home. We also opted to remove the gas service; instead, we use heat pumps to provide hot water and space heating. We also installed a 6.4 kW solar PV system.

Having gone to what is, by Australian standards, extreme lengths to improve the thermal performance of our home, we were keen to understand exactly how well it performed against our expectations and modelling. Knowledge is power—we want to be able to run our home in the most energy-efficient way and to do this we need to have a good understanding of how it functions. Thus we decided to install monitoring that is well beyond the norm.

The big picture
First up, we’ve kept track of our electricity bills. Over the most recent 12 months we have exported 20% more power to the grid than we have consumed and our net electricity bill was $627, of which two-thirds was the fixed supply charge. This bill includes cooking, hot water, heating and cooling as well as our plug-in hybrid car. The car accounts for about a third of our electricity consumption and this bill of $627 contributed to driving around 9000 km over the year in all-electric mode. If we were to exclude the car we’d have earned about $520 over the year.

Over the 12 months we exported 6071 kWh to the grid and imported 5135 kWh. Our consumption of around 19 kWh/day is high compared to many households, but bear in mind that about 7 kWh/day is used by the car, 2.5 kWh/day for hot water and in winter we’re using about 8–15 kWh/day for heating. Figure 8 shows our month-by-month consumption and export.

Read the full article in ReNew 144.

Image: igorr1 via iStock

Beat the winter chills: A guide to electric heating options

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As we head into the colder months, thoughts turn to staying warm. What’s the best electric heating system for you? Lance Turner looks at the options, and their pros and cons.

In past issues of ReNew we have focused on what are arguably the two most popular energy-efficient heating options—reverse-cycle air conditioning and hydronic heating. Both have advantages and disadvantages, and both suit some people, house designs and climates better than others, so which is best? Are there other options that should be explored? When it comes to heating, there are lots of questions to answer, and making the right choices is important for a comfortable, warm home with low running costs and low environmental impact.


Not gas
Firstly, we should note that we are not considering gas heating. Gas is a fossil fuel and there is simply no way to run gas appliances without greenhouse gas emissions. On the other hand, while electricity is in part generated by coal and other fossil fuels, it doesn’t have to be—you can purchase 100% GreenPower or install a solar power system large enough to cover your needs throughout the year and effectively be greenhouse neutral.

The economics of gas heating also no longer stack up in almost all cases. See for the ATA’s research report on this subject.

Now that is out of the way, what are the electric heating options available? Firstly, we will look at the two technologies we have covered previously which tend to be used for space (whole-of-house) heating—reverse-cycle air conditioning and hydronic heating, then we will look at resistive electric heaters, solar air heaters and other heating considerations.

Reverse-cycle air conditioners
Reverse-cycle air conditioners work by compressing a gas, called a refrigerant, which then transfers heat from one place to another. The technology that does this is called a heat pump. Heat pumps are all around us; for example, in your fridge, a heat pump transfers heat from inside the cabinet to outside, which is why the outside of the fridge gets warm. In a reverse-cycle air conditioner, the transfer can go either way, hence the name. In winter, heat is taken from outside and dumped inside, and in summer the opposite occurs.

Read the full article in ReNew 144.


Heating people, not spaces

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How much energy can you save by heating yourself instead of your home? Will you be as comfortable? Dave Southgate describes his personal heating experiment.

In late 2012 we moved into a fairly normal, five-year-old, four-bedroom home in the Canberra suburbs. As with many Canberra houses, it was a ‘gas house’, using gas for heating, hot water and cooking. Around this time, frustrated by the lack of government progress on climate change, we decided that we would set out to become a fossil fuel free family.


Getting off gas was clearly fundamental to our plans. More than half of our gas use in 2013 went into our gas ducted central heating—about 6000 kWh (21,600 MJ) over the year.

When we started out on our household energy transition, I envisaged that we would be using heat pumps to replace our gas heating (that’s what everyone else seemed to be doing!), but my wife, Donna, had other ideas. She said that heat pumps didn’t make her feel warm, so we began to search for alternative low energy ways to heat our house. It’s a long story which I’ve written about elsewhere, but we started by installing far infrared (FIR) heating panels. The main photo shows one of two FIR panels which we installed on the ceiling in our living/dining area.

Moving away from space heating…
The FIR panels produce a wonderful radiant heat and I was happy that my wife had diverted us onto a different path. However, when we first installed the panels we simply used them as space heaters and controlled the room air temperature using a thermostat. It didn’t take us too long (but probably longer than it should have) to work out that this was not very smart. When we were sitting under the panels the temperature of the air in the room had virtually no influence on how warm we felt. Our feeling of thermal comfort came from the direct radiant heat from the panels, not from the heat in the ambient air. Why heat all the air in the room when we didn’t need to? Consequently, we changed our heating habits: we only turned on an FIR panel when we were sitting under it and no longer worried about the room air temperature; the thermostat became redundant. This gave us some serious energy savings with no loss of thermal comfort.

This simple chain of events totally changed the way I now think about heating. I came to the realisation that what is important in heating is not how warm the air in a house is, but, rather, how warm the occupants feel! I quickly adopted the philosophy ‘heat people, not spaces’.

Read the full article in ReNew 144.


Heating case study: Converting gas to heat pump hydronic

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This 1908 weatherboard Edwardian in Melbourne has been renovated, extended and insulated—and is making the switch to all-electric, powered by solar PV and 100% GreenPower. In a project completed in November 2017, the owners replaced the gas boiler on their existing hydronic heating system with an electric heat pump, while retaining the original 25-year-old radiators.


Owner Peter Hormann says they did a lot of work to check whether a heat pump system would enable the 25-year-old radiators to deliver sufficient heat for their winter heating requirements. An important consideration is the lower operating temperatures of a heat pump system which is most efficient up to 55 °C (though can run up to 60 °C or 65 °C) compared to 70 °C from a gas hydronic boiler.

While working out their upgrade options, they limited their old gas boiler to 55 °C through two Melbourne winters to test the existing radiator effectiveness at lower system operating temperatures. “We found that with the lower radiator temperatures the room heating was more gradual and took an extra 30 minutes to bring the house up from a 17 °C standby temperature to our 21 °C ‘comfort’ temperature,” says Peter. To compensate, their household thermostat was programmed for an earlier start in the morning and late afternoon heating periods.

Chris Siddons from Siddons Solar Hydronics (who installed the new system) says that there are some advantages to having a lower water temperature in a hydronic system: “The plumbing fittings have a longer life at lower temperatures, and the radiators are a safer temperature for toddlers and babies.”

Another approach used with heat pumps is to use larger radiators, but Peter was keen to use the existing radiators, which, despite their age, were in good condition.

Read the full case study, plus several more, in ReNew 144.

Efficiently owner built

Efficiently owner-built: A warming tale

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Location, communication and efficiency are three key parts of this owner-build—along with an innovative hydronic heating and cooling system. Cathryn Hamilton describes the process and results for her house in Adelaide.

Owner building is all about communication. Well, at least for us it was, as we were project-managing owner-builders, rather than actual builders. Our main tasks were finding good tradespeople and coordinating them. It was great to be in control of the project, but it was also hard at times, and mistakes were made. But we love the end result and the house works exactly as we’d hoped.


What did we hope for? Our house building project began when my husband John and I became empty nesters and realised our six-bedroom home at the time would be much better used by a larger family. We also wanted to live closer to our jobs, to avoid long travel times and the consequent fuel use and transport footprint. But perhaps most importantly, we’d also spent time in the UK and Europe and seen just how efficient buildings could be, compared to our draughty, poorly insulated, single-glazed home.

We quickly realised we’d need to build rather than buy to get what we wanted at that time in Adelaide. In 2010, we found a 400 m2 corner plot, facing north-east, in a spot convenient for both our jobs, which we snapped up.

Soon after, we got the opportunity to participate in a university project. Architecture and construction student teams designed a home to meet our requirements, working with a budget of $350,000. Although the student designs didn’t quite fit the bill, it was a helpful exercise in working out what we really wanted—and in realising that our budget might need to be higher. The build ended up costing us almost double that original budget, due partly to the new technology we employed and the build quality we wanted.

A design for energy efficiency
The design process began in earnest in April 2011, when we discussed our plans with architect John Maitland from Energy Architecture. We’d met John previously when he opened his house on Sustainable House Day [Ed note: In a nice twist, Cathryn’s house opened in 2017 and is opening again at this year’s event on 16 September; see].

We’d liked John’s ideas about appropriate orientation and passive heating/cooling, using thermal mass combined with a hydronic system to maintain stable temperatures.

Our brief to him was for an energy-efficient home which would capture as much rainwater as possible for use in the home; the latter was particularly important to us in Adelaide’s dry climate. We also wanted a home that could age with us. We wanted wider doorways and ramps, and a ground floor that allowed for all daily activities (we needed a partial second storey given the small footprint).

Read the full article in ReNew 144.


On the solarcoaster: Fifteen years, five solar systems

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Jeff Knowles is a self-confessed solar enthusiast, and his rooftop bears that out with a higher-than-average number of solar upgrades that reflect changing installation standards. He explains the motivations for each iteration here—and the next chapter to come!

My partner Chrissy and I live in a purpose-built passive solar home in Jerrabomberra, NSW, near Queanbeyan and just over the border from Canberra. When you see that Canberra has had a run of 12 °C days, you might be tempted to think “ugh, that’s cold!”—mostly, though, we get a lot of sun with that 12 degrees and, surprisingly, winter can be a time when we generate more per day than Sydney or Brisbane using a similar-sized PV array.


Being a solar enthusiast, I have always been interested in how much we can generate on our roof. Our PV system has been an ongoing ‘project’ as the technology and our knowledge has improved. In fact, since 2003, we have had five iterations of our solar system—Solace #1 to Solace #5—using a variety of panels, inverters and optimisers—perhaps something of a record!

Solace #1: 2003
Solace #1 in 2003 used 12 x 150 W BP panels mounted almost flat on the roof. The installer hailed from Victoria and came up for the two-day install (as there were no local installers in the ACT in 2003, and the Victorian installer offered the best price and timeframe). The system was sized on paper—we calculated energy use in our all-electric home and what a panel could produce in a year in our region­—thereby arriving at 12 panels. It cost $20,000, before the $8000 government grant.

The system failed in its aim to produce as much as we used in a year, partly because of the way we installed it, with a long piece of steel to mount the panels. The steel got really hot in summer, and so did the panels. Hot panels are less efficient; keeping panels cool is ideal for maximum production of DC electricity. We finished up having to move them because, ironically, while the install was designed to produce the most in summer (they were only 12 degrees to horizontal), they were getting too hot to do so.

Read the full article in ReNew 144.

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ReNew 143 editorial: not just window shopping

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WHILE ReNew’s focus is normally in the energy arena, once a year we turn our attention to the building fabric, to consider sustainable materials/design and their energy implications. We’ve previously covered roofing and walls, and this time we give the lowdown on both floors and windows. Both of these really matter when it comes to energy efficiency.


Depending where you live, it seems that different sub-floor structures are in vogue. For example, in Queensland in descending order of prevalence are full concrete slabs, timber floors and waffle pods, whereas in the ACT it’s waffle pods that make up the majority of builds, according to 2016 analysis from CSIRO ( We look at all of these floor designs and consider their sustainability credentials, highlighting some excellent resources along the way.

Your final floor covering might be a concrete or timber finish (look for eco-products) or it might include colourful all-natural linoleum or beautiful bamboo. For all products, the eco-credentials will vary depending on source and the materials used. Our coverage aims to point you in the right direction and introduce you to materials you might not know about already.

Continuing our building materials theme, our buyers guide this issue is on windows. Windows consistently top the list of interest areas in our Sustainable House Day surveys. We’ve updated our guide to help you understand the choices from double glazing, to low-e coatings, to films or other treatments applied to existing windows. We’ve also tracked down nine case studies from readers who’ve upgraded their windows, from full replacement with high-performing windows through to secondary glazing of windows and DIY glass replacement.

As feed-in tariffs paid for solar generation exported to the grid have reduced over time, there’s been a lot of interest in what constitutes a fair rate. The ATA advocates for tariffs that reflect the many benefits of solar generation and has been pleased to see several state governments move in this ‘value-reflective’ direction. One big change on the horizon (in Victoria, at least) is a time-varying feed-in tariff, which rewards generation at the times of the day when the grid needs it most. We help explain the proposed tariff and estimate the benefits over a flat rate.

We also look at Paul Hawken’s Drawdown project, present an ‘almost off-grid’ experiment on the edge of Melbourne, cover how to prepare your home for an electric vehicle, plus much more. Who knows, with the current level of media coverage and new EV announcements, perhaps 2018 will (finally) be the year of the EV in Australia.

Until 6 July, we’re running our biennial reader survey. It’s your chance to let us know what you’d like to see more, or less, of in the magazine. It’s at We really use the feedback to guide our planning, so we’d love to hear from you

Robyn Deed
ReNew Editor

ATA CEO’s Report

AS WE change seasons, so does the inside temperature of our homes. For the majority of Australians living in energy-leaky 1 or 2 Star homes, it means going from being too hot in summer to too cold in winter, unless a substantial part of energy bills is spent on heating or cooling.

Helping to empower people to make their homes more comfortable to live in, cheaper to run and not cost the earth is what the ATA has been doing for 38 years. The great examples of what people have achieved in their own homes have filled the pages of many issues of ReNew and Sanctuary magazines.

As well as providing practical, independent advice, the ATA advocates for regulatory change to improve home performance. Currently in Australia all new homes and alterations/additions need to achieve a minimum 6 Star energy rating to comply with the National Construction Code. However, it is well-recognised that many homes are not performing at 6 Star once built. There is also an increasing body of evidence that the economically optimal level of new housing should be above the minimum 6 Stars.

According to a recent report from the Australian Sustainable Built Environment Council, 58% of Australia’s buildings in 2050 will be built after 2019, so improvements to the code and optimal performance are critical over the next few years.

The ATA is taking the lead and working with our partners in representing households and advocating for change to the code. We all deserve to live in comfortable, healthy homes that are resilient in a changing environment. You can support our work by making a tax-deductible donation to the ATA at


You can purchase ReNew 143 from the ATA webshop.


Window and film buyers guide

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Poorly performing windows can drag down the thermal performance of your home. Lance Turner looks at some solutions.

Reducing heat flows through windows and doors is critical for maintaining a comfortable temperature during weather extremes. Heat flowing through an unprotected single-pane window can be considerable, affecting the thermal performance of an otherwise well-insulated house. In fact, a single-pane plain glass window has almost no insulating ability—around R0.2.


The Australian Window Association (AWA) estimates up to 40% of a home’s heating energy can be lost through windows and up to 87% of its heat gained through them. Choosing high-performance windows, combined with sensible window placement, insulating blinds and other window improvement methods such as special films and coatings, can reduce energy costs and improve thermal comfort. Understanding how different windows interact with the design of your home can be key in window selection.

Heat transfer
There are three main ways heat transfers through windows: radiation, conduction and air infiltration.

Firstly, heat is lost by indirect radiation. Warm objects inside the room radiate heat at long wavelengths (between 5 and 40 micrometres). This energy cannot pass directly through plain glass as it is opaque to such long-wavelength radiation. However, some radiant energy is absorbed by the glass and this is conducted through the glass to the outside. In summer, the reverse occurs, with long-wavelength radiant heat (radiated by hot air and hot surfaces outside) passing indirectly through the glass into the room.

Still greater is the transmission of radiant short-wavelength solar energy—consisting of visible sunlight plus near-infrared radiation—which is largely transmitted directly through clear glass.

Secondly, heat is lost through conduction—direct transfer of heat from the warm side of the window to the cool side. In aluminium frames with no thermal break, heat is conducted up to six times more readily through the frame than the glass, as aluminium is such a good heat conductor.

In winter, conduction from inside to outside also drives a convection current on the inside of the window, accelerating the rate of heat loss. Warm indoor air cools when it comes in contact with cold glass and falls to the floor, drawing in more warm air from above. This heat loss method can remove a great deal of heat from a room.

A final method of heat transfer is air infiltration. This occurs when air leaks through the gaps between the inner frame (that holds the glass) and the outer frame (head, jambs and sill). Poorly sealed windows result in a high air infiltration rate and poor thermal efficiency due to the transfer of warm air. This is particularly an issue in areas that see higher winds.

How do you know which glazing system or treatment is the best solution for you? It’s a complex task for the average homeowner, so here we look at window performance measures and the types of glazing you can choose from.

Read the full buyers guide in ReNew 143.

Download the full buyers guide tables here.


The right floor for your build

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When building, you may put a lot of thought into the floor coverings, but what about the sub-floor structure? Both are important to ensure a sustainable result. Lance Turner surveys the options.

When building a home, often very little thought is given to the type of flooring and sub-floor structure used. Yet different sites need different materials, with some being far more appropriate for particular sites. The design of the rest of the house will also help determine the type of floor and sub-floor used.


Your architect will have good ideas about the best flooring system to use, based on their experience with the type of building system you are using and the site specifics. But it helps to have a good understanding of the flooring systems available, so that you can consider the pros and cons of different systems and materials, and ensure that your sustainability or other requirements are met.

So let’s take a look at the most common types of flooring systems (or, more accurately, sub-flooring systems), the materials most commonly used and the types of flooring materials they can support.

Flooring requirements

A floor/sub-floor system must obviously be able to bear the entire load on top of it, potentially including the house, contents and occupants (some floor structures, such as upper floors, will only need to support the contents/occupants).

The floor’s footing system must be suitable for the type of soil you have on your block. A soil report will be required which will tell you your soil type and how reactive it is. Reactive soils are soils with a high clay content which swell when wet and shrink as they dry. This expansion and contraction can cause structural cracking, sinking and other site issues. See for a quick rundown of soil types.

The level of insulation required for your home will also be a factor in the type of floor you select. If you are in a cold climate then you will need a highly insulated floor, so an insulated slab or a floor on stumps that can be insulated underneath will be required.

Of course, durability is also important: the floor must last the life of the home—for example, you don’t want to have to be restumping in 10 years due to degradation of the stumps or soil movement.

Thermal mass must also be considered if your house design makes use of it. A slab provides high levels of thermal mass, although heavyweight walls (on the room-side of the insulation) tend to provide better thermal mass both in winter and summer than do concrete ground slabs. Other floor types can have thermal mass added using a number of methods, from thick ceramic tiles or slate, to adding PCMs (phase change materials).

Read the full article in ReNew 143.

Download the summary tables here.

Artists impression The Paddock 2 600px

Living Building Challenge in Castlemaine

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Central to the Living Building Challenge is design that takes account of much more than thermal performance, such as giving back to the local economy. Sasha Shtargot looks at one of the first projects taking this on in Australia.


When architect Geoff Crosby was approached in 2008 by Neil and Heather Barrett about their plans to develop an eco-housing estate, The Paddock, on their 1.4-hectare site in Castlemaine in central Victoria, he was keen to find a rigorous green design framework.

Geoff had been to a talk at Melbourne University about the Living Building Challenge (LBC) and was impressed enough to do some more research and eventually use it in his own work. The framework appealed because it was thorough in its approach to sustainability and it accorded with his own philosophy of tackling issues like water conservation, community and connection to nature firmly through a local lens: “My perspective is that good things come from the local context—you get much richer solutions that way.”

The LBC “ticked all the boxes” for both him and the green-focused site owners. The building standard, set up in the USA in 2006 by the International Living Future Institute, consists of seven performance areas, known as ‘petals’: place, water, energy, health and happiness, materials, equity and beauty. The aim of the LBC is to create excellence in green design; it visualises the ideal building as functioning as cleanly and efficiently as a flower with many petals.

The standard seeks to create healthy, regenerative and efficient spaces that give more than they take out of the environment, making a positive impact on people and nature. Geoff describes it as “the most rigorous and realistic approach to sustainable design he has found so far.” Sustainability academic (and keen supporter of the LBC, and this project) Dominique Hes notes: “There’s a reason it’s called a challenge!”

Read the full article in ReNew 143.

New extension

Material beauty

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Dion and Amy Zappacosta’s reno included some interesting material choices, including a raised timber floor rather than a concrete slab, recycled materials and eco-finishes. They describe how they went about it, and the results.

BACK in 2013, our family of four was looking for a new home in Wollongong, NSW. One of our main criteria was that it be on a flat block, as our previous home was a pole house on a very steep block—not great for family living! We were also looking for a house where the kitchen faced the backyard, and the yard itself had the potential to be kid-friendly and accommodate a decent vegie garden and fruit trees.


The house we found wasn’t ideal, but it had potential. A timber-framed weatherboard, around 80 years old, it was showing its age, but still retained some of the charm of its era.

There were lots of problems. It was suffering from some pretty average additions and modifications done in the 60s, including a filled-in section of the western verandah and an unattractive bathroom/laundry fibro extension. The layout and thermal performance of the house wasn’t great, as we found after living in it for 18 months. It was cold and draughty in winter, with only a sliver of winter sun landing on the kitchen bench. The high ceilings and steep pitched roof helped in the summer, but cross-ventilation was non-existent and most evenings were warm and clammy. The bedrooms and living room were a decent size, but the kitchen/dining space was very cramped. We knew we could work with it though.

The advantage of using an architect

From the outset we knew we wanted a bit more space and to improve the layout and remedy some of the dodgy alterations. We had no intention of demolishing the original part of the house, and were looking to improve the kitchen, dining, bathroom and laundry, as well as add some living space. We also wanted to do it in a way that improved the thermal performance of the house and not have to sit at the breakfast table shivering in a dressing gown and slippers!

We talked to architects and draftspeople with a brief of wanting to make sustainable modifications which incorporated passive solar design. The choice to go with Andy Marlow from Envirotecture was easy. We developed a good rapport with him from the first meeting; being aligned in our views on sustainability and the environment was a great reference point for discussing the designs and materials Andy had in mind.

The architectural fees through to start of construction can be daunting at first, but we decided the value of having an architect on board far outweighed this. Andy found ways to include what we wanted on a smaller construction footprint, which reduced our costs significantly. The comfort the finished house provides is also superior to what we could have specified ourselves. The specification schedule and scope of works documents vastly simplified the builder engagement process and the build itself.

Read the full article in ReNew 143.

Double-glazed windows waiting to be installed

Glazed and enthused: Window replacement case studies

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Replacing the entire window with a new double-glazed one was the answer to greater energy efficiency and thermal performance for these homeowners.

Switching to double glazing as part of a renovation
by Anna Cumming


Last year, we did a small renovation at the back of our 1920s Californian bungalow in Melbourne’s north, opening up the space across the back of the house and putting in a new kitchen. As part of the renovation, we installed glazed French doors opening onto our deck and new windows in the kitchen; we also took the opportunity to replace ugly aluminium-framed windows in our living room and a bedroom with efficient new windows.

We wanted timber frames for aesthetic reasons and to fit the character of the house. Sustainably harvested, ideally local timber was important to us, and I wanted the flyscreens to be timber-framed too as they are internal and thus quite visible.

For thermal efficiency, we upgraded to double glazing, but did not dig too deeply into the precise performance specifications of the various options as we are realistic about our old, leaky weatherboard house—basic double glazing would definitely be an improvement, but top-spec windows, low-e coatings and so on probably not worth the extra money!

Our first step was to decide on sizes and styles and put together a brief for our four new windows and one glazed door unit. Two of the windows were direct replacements for medium-sized existing ones, although we opted for casement openings to catch breezes instead of sliding openings.

In the new kitchen, we replaced a large west-facing window that had admitted far too much afternoon sun with a long, narrow fixed glazing ‘splashback’ window between the new benchtop and overhead cupboards; above the sink on the north wall we decided on a 1100 x 1800 mm window with a sliding opening.

In the centre of the north wall, we replaced the existing single back door with a pair of double-glazed doors we’d been lucky to acquire for $100 several years earlier from a neighbour’s builder—they had been made the wrong size for the job. As part of our windows order, we had a frame made to fit the doors, with an extra window pane on one side.

We sent the brief (see box in article) to seven window manufacturers, a list combining recommendations from friends, companies whose work features regularly in the homes profiled in Sanctuary magazine, and some joineries local to us in Preston that we found via internet search. Comparing the quotes was trickier than merely looking at the final figures (which ranged from $4100 to $8300), as despite responding to exactly the same brief, the detail of each company’s offering was different.

Read Anna’s full case study and two other window replacement stories in ReNew 143.

Fitting secondary glazing

Doubling up: Secondary glazing case studies

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We hear from a variety of householders about their window upgrades using secondary glazing and retrofitted films.

Film + DIY secondary glazing
by Jasper Lee


My wife Melissa and I purchased a three-storey 1980s double-brick townhouse in the inner eastern suburbs of Adelaide back in the middle of 2016. We were new to Adelaide, but quickly became aware of the climate extremes during summer and winter. As Melissa works at home, and we have a toddler at home as well, thermal comfort was important for us, and we wanted to achieve this in a sustainable manner. We had made some basic DIY draughtproofing upgrades at our last property, a rental, with the permission of our landlord, but really wanted to make major improvements now we owned our own home.

Prior to our purchase, the house had been rented out for several years and little had been done to improve its energy efficiency. We had a six-month overlap while we were still renting, so we had time to plan and execute our retrofit upgrades. We started with the low-hanging fruit first: draughtproofing doors, windows and skirting boards. We also took advantage of the support from REES, the SA government energy efficiency program, to upgrade all lighting from halogens to LEDs. We also discovered that the cathedral-style ceilings were missing any form of insulation, so improved this with blow-in Rockwool insulation.

The next things we tackled were the windows. We took a bit of a mixed approach, based on the window aspect and usage, and we staggered the upgrades over the time until we moved in. Our approach was also governed by cost. Replacing the windows or changing their sizes/position would have set us back in excess of $20,000, compared to the $2000 we spent on upgrading 14 window panes with window film and secondary glazing. We did replace a poorly functioning back door with an argon-filled uPVC double-glazed sliding door, because it needed to be replaced anyway; this cost $3300.

Read Jasper’s full case study and 3 other secondary glazing stories (on Magnetite, EcoGlaze and a DIY approach) in ReNew 143.


New glass is greener: Retrofit double glazing case studies

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Retaining perfectly functional window frames and replacing the glass with double-glazed units can save money, as these homeowners discovered.

Retrofit double glazing by Thermawood
by Carolyn Nguyen


The 1960s-era house we bought in 2014 had a compact footprint and good solar orientation. We recognised its potential and thought we could dramatically improve thermal comfort and reduce our power bills with the right kind of improvements. We started small: heavy curtains, pelmets and external awnings. In the ceiling, compacted loose-fill insulation was replaced with R4 polyester batts. Old air conditioners and gas ducted heating were replaced with energy-efficient split systems from Daikin.

Having installed new double glazing at a previous property, we knew of its benefits firsthand. It was initially at the bottom of our to-do list, however, because we felt the payback wasn’t worth it.

The first couple of winters made us reconsider our position. Our indoor toilet, with its louvred window, was effectively an outdoor room. In the bedrooms, warm air hit the glass panes and condensation would form.

Our old house had uPVC double-glazed windows from Ecostar. While they were low-maintenance, they required expensive specialty flyscreens and the uPVC aluminium look appeared at odds with the facade.

With the new house, we didn’t want to install windows that might polarise future owners, potentially resulting in the removal of said windows or the demolition of a perfectly functional building, so we knew we wanted wooden-framed windows. We also wanted to replace the louvres in the toilet with a fixed pane to minimise draughts, and replace the kitchen’s casement window with a bi-fold.

To replace all 10 windows (30 panes) with new high-performance double glazing and joinery, we got a quote of around $48,000 (in 2016), including an installation cost of $5000. Would that product match the house’s 60s aesthetic? We weren’t sure.

We decided to look at other options. One that appealed to us was from Thermawood. This approach reuses the existing window frames, so replacing nine windows with double glazing (28 panes)—the kitchen window was to be replaced entirely—would maintain an important original feature of our period home. Added benefits included saved resources and waste reduction. Plus, it would only cost $13,250. Unlike secondary acrylic glazing that is preferred by some retrofitters, Thermawood replaces the original panes with insulated glass units (IGU), which come with the option of being filled with a low conductivity gas (i.e. argon) and can be recycled at the end of their life.

Read Carolyn’s full case study and a DIY retrofit double glazing story in ReNew 143.


ATA member profile: A window on a life in building efficiency

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A physicist by training, Peter Lyons has spent two and a half decades involved with housing energy efficiency—in particular the role of windows, and windows ratings systems. He talks to Anna Cumming.

After finishing his PhD in cosmic ray astronomy at the University of Tasmania in the early 1980s, ATA member and Canberra branch convenor Peter Lyons made the move to the ANU to work in their very high speed wind tunnel project.


“Some of our work was in collaboration with NASA,” he recalls. “We helped design nose cones for unmanned spacecraft that went to Saturn and Jupiter!”

His involvement with the built environment began as part of the Solarch research group in UNSW’s School of Architecture in 1992. “Headed by Professor John Ballinger and CSIRO, we did the early work on housing energy efficiency that led to NatHERS and other energy rating software tools,” he says.

At the same time, the group got involved with an international collaborative development project on advanced glazing, helping coordinate work that was already going on in research institutions and private industry in ten countries. “That consolidated my interest in windows as an important part of the building envelope and a key factor in whether a building would be energy efficient or not.”

This led to a stint at the University of California at Berkeley where he worked on the connection between windows and thermal comfort.

“Everybody knows that windows in winter can make a space feel cold or hot, because of radiant temperature that is lower or higher than the desired air temperature. I worked on what was to be the beginning of a procedure for rating the thermal comfort impact of windows. Say you’re one to two metres from a window; will you be more or less comfortable than if the window wasn’t there?”

Later, he took up a position with the Australian Window Association as the first manager of the WERS energy rating scheme for residential windows, which was launched in pilot form in 1996.

These days, he runs his own consulting firm, offering design development advice on energy performance to the window and glass industries, full window system modelling, and building energy modelling. “Our clients are mostly designers and specifiers who need help with making decisions about windows, shading, and the combination,” he says.

Peter and his family have lived in a passive solar designed house since the 1980s, and he’s been a member of the Australian and New Zealand Solar Energy Society (now the Smart Energy Council) for years.

“A few years ago I became aware of the ATA—there is quite a crossover in membership between the two groups in Canberra—and I joined because I could see straight away that the ATA was extremely practical.”

He’s now been the ACT branch convenor since 2015. “Our branch is a big group with well-attended meetings, which I look forward to every month.”

Peter says he really enjoys the interaction with other ATA members locally and more broadly, noting that in many cases they are people he’s known professionally for years; further, he says that in Canberra, ATA branch activities often overlap with other professional bodies like the Australian Institute of Architects, allowing satisfying cross fertilisation of ideas.

Peter is fascinated by electric vehicles. “I have a hybrid car, but I realise it’s only a stepping stone. I really look forward to the articles on EVs in ReNew. Anything we all at the ATA can do to try to push the government to speed up adoption of EVs and the inevitable electrification of transport would be a great thing.”

“I really enjoy applying physics and good science to sustainability,” Peter concludes. “For me, the way I do that is through building energy performance, the building envelope—especially windows, which have always fascinated me. I guess I’ll do it until I retire. Even after that, I’ll be a keen ATA member!”

This member profile is published in Renew 143. Buy your copy here.

142 Front cover 150dpi full size

ReNew 142 editorial: to boldy solve the split incentive

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THERE are some great landlords out there, providing comfortable, energy-efficient housing for the 31% of Australians who rent. But there are also many cases of poorly maintained and poorly performing rental properties. With New Zealand bringing in minimum standards for energy efficiency measures such as insulation, it’s time for Australia to step up. The states have some schemes in place, but much more is needed, including incentives and regulations.


We look at what’s happening in Australia, what landlords can do (and what some are doing already), and the energy efficiency scorecard currently being trialled in Victoria that may help push the market in the right direction.

Another area where renters often miss out is the savings that come from solar. The same goes for apartments, where it can be difficult to install solar for many reasons, including technical. But both markets can and are being catered for. We look at what’s possible to solve the solar ‘split incentive’ and look at case studies of solar panels making their way on to this under-used rooftop resource: a win for landlords, renters and the environment.

Our buyers guide this issue is on solar panels. Although many ReNew readers may already have systems, there are still many rooftops without solar (including rental ones), and many readers may be looking to add a larger system to their existing one. We also follow one person’s story of their recent solar install: how they did their research and sizing, and the process from accepting the quote through to receiving a feed-in tariff for their homegrown clean energy.

Over the past year, the ATA has been advocating for a transition to a 100% renewable grid for Australia. Andrew Reddaway’s report from last year asked if it was possible (answer: yes, and by 2030). This time he investigates how Australia is progressing. It seems that a clear transition is underway, with many projects in the pipeline, all renewable. But it requires proper planning, which has been lacking to date. Andrew’s work shows just what a plan might look like. It’s inspiring, and maddening at the same time: it’s affordable and possible to do this within 13 years, yet we are sitting around debating whether we should allow Liddell to close or not.

There’s much more in the issue besides. We look at PV recycling, present an induction cooktop mini guide and give an update on the growing (at least elsewhere) EV market. Beyond solar PV, Tim Forcey argues that we all need to become familiar with the term ‘renewable heat’. As he says, in his home, just 20% of his home’s renewable energy comes from solar—the other 80% comes from heat from the air, used by his hot water heat pump and air conditioner.

We hope you enjoy the issue. The ReNew team wishes everyone a relaxing and safe holiday period and we look forward to hearing from you in the new year.

Robyn Deed
ReNew Editor

ATA CEO’s Report

In Australia, renewable energy and carbon emission targets are again being used as a political football, in which there are no winners. In fact, it’s hard not to feel that each time we take two steps forward with action on climate change, we also take three steps back.

However, despite community frustration with political leadership in this area, there are positive stories to tell. The momentum for a low-emissions future grows apace with the price of renewable energy continuing to fall—it is now cheaper to develop solar and wind energy than new coal-fired power stations in most countries. And we have industry leaders calling for certainty on energy policy so that they can get on with the job.

The good news is that the knowledge, technology and solutions to enable households and communities to reduce their carbon emissions and save money are available.
With electricity prices continuing to rise, new technologies such as batteries and heat pumps coming on to the market and more Australians wanting to take control of their energy future by producing their own renewable energy, there is a need more than ever for quality, independent information for households. That’s where the ATA and our commitment to providing quality independent advice comes in, most recently with our free online solar & battery sizing tool. Find it at

At the ATA every year we are helping hundreds of thousands of people make a practical difference and we’ll keep doing this through 2018. Thank you to all our members, partners and supporters who are part of our community of change.

Donna Luckman

You can purchase ReNew 142 from the ATA webshop.

Rental house

Landlords leading the way

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Landlords can take steps to make their investment more comfortable and efficient to live in. But with many measures at the landlord’s discretion, is it time to enforce a minimum standard in rental houses? By Jacinta Cleary

Those looking to rent a home often have no way of assessing the energy efficiency of a place, other than what they can glean from a rapid house inspection with tens of other house hunters in attendance.


The dwelling’s energy efficiency often becomes apparent on the tenant’s first hot or cold day in the house, though, when the sun hits the uninsulated extension tacked on the back of the home, or there’s a cold draught through a gap in the wall. The heating is switched on, or the air con if there’s a system in place, and the winter and summer electricity bills steadily rise.

Switched on tenants who can afford the upfront cost will make their own modifications to improve thermal efficiency, with window coverings for instance to keep the heat inside in winter, but it’s really a landlord’s responsibility to increase the energy efficiency and year-round comfort of their investment property.

Australia’s rental houses are only required to meet the building standards that were in place when they were built, which for some homes could be 100 years ago. With this disparity in mind, Environment Victoria is campaigning as part of the One Million Homes Alliance for a common minimum standard for Victoria’s rental houses. Campaigns in other states include the ACT Comfy Homes campaign, which is calling on the ACT government to establish a similar minimum standard.

As well as the environmental benefits that energy efficiency upgrades bring, the campaigns bring attention to the social issues associated with living in a house that’s uncomfortable and unaffordable to run. Environment Victoria’s Bringing Rental Homes Up To Scratch report highlights that Victorians are renting for longer due to home ownership being increasingly out of reach, with the share of households renting for more than ten years doubling since 1990 and, of the 600,000 rental households in Victoria, the proportion of families with children has risen to 37%. Inefficient housing can have a negative impact on health, especially that of the very young and elderly. ABS data found that renters were the largest group of households unable to heat their home (37%) or pay their bills on time (42%), yet they are around half as likely as owner-occupied homes to have basic energy efficiency measures such as insulation that would help reduce bills.

Read the full article in ReNew 142.