In ‘Energy efficiency’ 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.

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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.

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.

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.

Drawdown editor Paul Hawken

Drawdown: a plan to reverse global warming

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Paul Hawken’s Drawdown project brings together peer-reviewed science on the “top 100 solutions to climate change”, highlighting the benefits and costs of each. ATA member Tom Hunt met with him recently in Melbourne.

IN February, I was privileged to meet Paul Hawken in Melbourne while we were both touring Australia. I was merely on holidays while the US environmentalist, entrepreneur, journalist and author was presenting the Drawdown project to a large and enthusiastic audience at an event organised by Sustainability Victoria at RMIT.


Drawdown, the book, is Paul Hawken’s latest bestseller, but it is far more than a well-illustrated and readable tome. It represents the combined work of 70 scientists and researchers, and tells an inspiring story of the most important things we can do to combat climate change. It calculates just what we can achieve in terms of greenhouse gas emission reduction by applying the technologies and knowledge already at our disposal. The book is supported by the website, which also presents the data in a very accessible way, gives more information on the methodologies and updates the results as research continues.

Deciding what’s important
So what is the most important thing to focus on in the battle to combat climate change? Is it more important to replace coal with wind turbines, to put solar on every rooftop, to switch to electric vehicles or just to stop eating meat?

This is the type of question many people have posed, but few have properly explored. Back in 2001 Paul Hawken started asking the experts: “Do we know what we need to do in order to arrest and reverse global warming?” But the experts had no overall picture, only the knowledge within their own spheres of expertise.

Greenhouse gases are at an all-time high. In 2013 Paul was so concerned by talk of the unthinkable ‘game over’, he decided to pull together all the experts he could and work out, for us all, just where we stand on global warming with the options we have.

Read the full article in ReNew 143.

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.

Energy Efficiency Scorecard assessment

Scoring your home

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Energy efficiency scorecards promise a way to compare homes and kickstart energy efficiency and liveability improvements, for both renters and homeowners.The ATA’s Katy Daily looks at how the Victorian government’s Australian-first scorecard scheme could help her draughty rental home.

SINCE moving from the USA to Melbourne six years ago, my family of four has been renting a tastefully restored 1926 art deco weatherboard. And, in the typical refrain you hear from almost every immigrant from a colder climate, I’ve never felt as cold as I did that first spring in Australia.


Working at the ATA armed me with plenty of ideas for things I could do as a renter (and that we can take with us when we move) to make our draughty home more energy-efficient: we’ve replaced almost all the lights with LEDs, installed a Methven Kiri showerhead, added a Valvecosy to our hot water system and started insulating the hot water piping, and bought an energy-efficient refrigerator and washing machine.

We’ve done a good job of getting our electricity usage down to a respectable 4 kWh/day on average, but the house leaks like a sieve and my partner and I are both loathe to turn the heat on just to heat up the neighbourhood! As a result, our house is very uncomfortable in the winter and can be oppressive on very hot, still days and nights. We’ve been wanting to approach our landlord about draughtproofing, solar and other improvements to help make the home more comfortable while maintaining the low running costs, but didn’t know how to start the conversation.

Enter the Victorian government’s new Residential Efficiency Scorecard which rolled out in 2017. The scorecard is an Australian-first home energy rating program that gives (yet another) star rating, this time for your home, on a scale from 1 to 10, similar to the energy use star rating on a fridge or washing machine. Not to be confused with the NatHERS Star rating which describes the thermal performance of a home, the scorecard rating represents the running cost of the fixed appliances in a home (heating, cooling, lighting, hot water and pools/spas) and is intended to be used as a guide to make home improvements efficiently and cost-effectively.

Read the full story of Katy’s assessment in ReNew 142.


Induction cooktop mini guide

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Induction cooktops can make converts, with power and performance as good as or better than gas. We look at the features to consider when buying one.

If you’re planning to go all-electric—to reduce your bills and carbon footprint as suggested by ATA analysis (see—you’re going to need an electric cooktop. Not so long ago, that meant an element-style cooktop with all the downsides that went with that: slow response to turning the heat up or down and the consequent risk of burnt fingers (or melted implements) as the elements stayed hot for a long time after being turned off. Many keen cooks favoured gas cooking for these reasons—but induction cooktops are changing that.


Should I go induction?
In ReNew, we’ve recently covered several stories about readers’ satisfaction with the switch to induction; in fact, many would call themselves induction converts who would never go back to gas.

Fans of induction cooktops cite many advantages—fast performance, excellent temperature control from low to high, increased safety as the cooktop doesn’t get as hot, ease of cleaning of the flat surface and, last but not least, energy efficiency.

There are a couple of disadvantages which can make the switch more costly for some. One is that you may need to replace your saucepans and frypans. Most new cookware is induction-compatible, but some older cookware fails the ‘magnet’ test. See ‘Cookware requirements’ for more on this.

Another potential cost is that you may need an upgrade of your electrical switchboard or the wiring to your kitchen. Induction cooktops have varying power requirements, but all are likely to require 20 amps or higher, up to 42 amps. See ‘Installation and power requirements’ below for more on this.

Cooking with science
The speedy performance of induction cooktops can seem like magic, particularly if you’ve experienced the slow response of electric element cooktops. But it all comes down to science.

They work by producing an oscillating magnetic field. Because the magnetic field is constantly changing, it induces a matching flux into any magnetic cookware on the cooktop. This induces very high currents in the cookware, causing the cookware to get hot due to the metal’s electrical resistance.

Because the pot is heated directly by the magnetic field, the amount of power being fed to the pot, and hence the running temperature of the pot, can be varied almost instantly, giving induction cooktops heat control capabilities as good as or better than gas.

Features and considerations
When you’re buying an induction cooktop, there are a few considerations to make sure that the cooktop you buy will suit your needs and will be easy to use.

Featured image: Samsung

Read the full article in ReNew 142.

Grid voltage corrected infographic

Renewables improving the grid

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An innovative trial is using smart solar inverters on homes, both on their own and combined with batteries, to improve grid stability. By Lance Turner.

Many Australians are all too aware how unstable the electricity grid can be at times, especially under large loads, such as when everyone gets home and cranks up the air conditioner on a hot day. Other factors that can affect local grid stability can include large numbers of distributed generation sources (such as home PV systems) in a small area, long grid distribution lines, and old, poorly maintained or undersized grid equipment such as transformers and cables.


The result can be a number of problems (see Figure 1), including low or excessive grid voltage, low or high grid frequency or poor power factor (a mismatch of the voltage and current waveforms).

While upgrading grid equipment is one possible solution, it’s not the only answer. Long feeder lines experience both increases and decreases in voltage along the line due to the natural impedance (like resistance) of the cables—homes a long way down the feeder can see an ohm or more of impedance between the substation and the home.

At times of light load (energy consumption) but high PV generation, such as the middle of a sunny weekday, the feeder may see a steadily increasing grid voltage along its length; for each ohm of impedance along the feeder line, every amp flowing into the grid raises the voltage on the grid by 1 volt. For example, each 5 kW solar system can be adding 20 amps into the grid, or an increase of up to 20 volts above the other end of the feeder line. In the evening when solar generation is almost zero but demand is high, this same grid impedance causes the voltage to sag. Thus, the voltages along the feeder, especially towards the far end, can vary widely (see Figure 2).

A good example of how extensive the problem can be is in Figure 3, which shows the high and low grid excursion events (where the grid voltage tends towards the allowable limits) for a selected substation over a two-year period.
Although this can be mitigated by an increase in cable size to lower resistance and installing transformers with a higher capacity, such upgrades are expensive and can never eliminate voltage variation caused by system impedances. So, other, smarter options are now being considered.

Read the full article in ReNew 142.

ReNew 141: Store your solar

ReNew 141 editorial: measure it up – the benefits of monitoring

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I’M A big fan of energy monitoring. Most days we check the app from our electricity retailer to keep an eye on usage from the day before. Broken down into half hourly blocks, this proved particularly useful to see the (good) results as we switched out halogen lights for LEDs and got better at turning things like the computer and printer off when not in use (hibernation mode on PCs means you can easily pick up where you left off, and an ecoSwitch is great for quickly turning off printers or TVs). The app also keeps historical usage so you can compare winter to summer, or this winter to the last, useful for spotting a problem energy-user (a plug-in heater perhaps), before the costs start to add up.


Taking it a step further, you can even get near-real-time monitoring. Having just installed a solar system, I’m now a convert to its app which shows almost instantaneous solar energy production and electricity usage. Such real-time data makes it even easier to work out what’s chewing up energy—or as happened today, to tell whether your child has turned on the washing machine as promised while you’re out! Plus, the generation data helps you schedule appliances to run at a good time for solar self-consumption or to work out if your solar system is performing as expected.

In this age of Internet of Things and wi-fi connectedness, there are now so many more options for energy monitoring: some connected to a smart meter, some to a solar or battery system and others independent of these. Our guide helps you understand which type might work for your situation—definitely worth a look to help you reduce your bills and environmental impact. It’s just a pity the same tools aren’t available for gas monitoring.

Our other big topic this issue is energy storage—perhaps more of a barbecue-stopper than energy monitoring! It’s been heartening to see grid-scale battery developments in South Australia and Victoria, as a way to provide grid stability and assist with peak demand. There are solutions other than keeping ageing coal-fired power stations like Liddell open.

It’s great to see early adopters of home battery systems in our audience. Their ‘use cases’ will provide insights and help the market develop—similar to the role many ReNew readers played in the early solar days. It’s also good to see industry trials underway to measure the community benefits, plus government subsidies which a few of our case studies have been able to access. We’ve reviewed the market to provide pros, cons and the range of battery systems available. It’s a rapidly developing area, so we’ll keep providing updates and case studies to help guide your approach.

Plus: ‘home truths’ on how comfort and efficiency can go hand-in-hand, a heat pump hydronic system in action, using ratings tools during rather than after the building design process (there’s even a free tool available so you can DIY), second-life for EV batteries, DIY garden irrigation, a community aiming for net zero energy and much more. Enjoy!

Robyn Deed
ReNew Editor

ATA CEO’s Report

AS ReNew goes to print we are in the final stages of preparing for Sustainable House Day 2017. We are very excited to have 200 homes opening up across Australia, with 20,000 people expected to visit one or more of these homes on the day. The event provides a unique opportunity for people to come and learn how to make their homes more environmentally friendly, more comfortable and cheaper to run.

A diverse range of homes are opening their doors, including granny flats, student rental accommodation with battery storage, new contemporary 10 Star homes and homes where the owners have made gradual changes over a number of years. What they all have in common is that they’ve worked hard to improve the energy efficiency of their homes.

The average Australian home has an energy efficiency rating of just 1 to 2 Stars, making them cold in winter and warm in summer. Draughty and leaky, these homes use about 40% of their energy on heating and cooling. By walking into a well-insulated home you can instantly feel the difference in comfort.

We are also seeing new trends with an increasing number of homes that are all-electric and more homes incorporating battery storage or at least planning for future installation. They must have been keeping up-to-date by reading ReNew!

Sustainable House Day would not be possible without the generosity of the households opening their doors and over 200 volunteers who help out on the day. They are all part of ATA’s community of change, not only taking practical action for a sustainable future themselves but sharing their experiences and inspiring people in their community to do the same.
Donna Luckman

You can purchase ReNew 141 from the ATA webshop.