In ‘Energy efficiency’ Category


Energy out west: A second life in sustainability

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How do you get into energy auditing as a career? And how do you run an audit? Alan Benn’s experiences provide insights helpful to those looking to get into the field, and those wanting to audit themselves, or friends and family—or even their local school! By Robyn Deed.

As a semi-retired electronics engineer with a keen interest in sustainability (perhaps a common ReNew reader profile!), Alan Benn’s move into energy assessment work allowed him to combine his technical skills with his sustainable self.


Based in Perth, Alan’s career change began with a six-month energy auditing course in 2010/11, via a federally funded Green Skills course run by the WA Council of Social Services. Starting with the two-week Home Sustainability Assessment course, it moved to auditing of workplaces in the not-for-profit community sector. As well as hands-on training doing assessments, he learnt technical info, across energy, water and buildings—”that’s where I first learnt about window U-values,” he says.

Although the course was excellent, of 75 trainees (most retraining to start a new career), only three or four are now working in the field. He notes: “Running a business like this can be hard, and there’s little work in energy assessments, particularly residential assessments.” Alan has been a volunteer with Perth-based community association Environment House for over 10 years and most of his paid auditing work is on their auditing contracts with local councils. Some programs are targeted at low-income residents, but most are open to any ratepayers. He’s done assessments from “little retirement units to mansions using 80 kWh/ day of electricity”.

An exercise in understanding

A big part of an assessment, he’s found, is explaining energy and water bills: helping the resident to understand their usage, what the units charged for mean, how usage changes over the seasons, and what’s a reasonable level of usage for gas, electricity and water, depending on the appliances installed.

“So few people know about energy costs,” Alan says. He often asks how much petrol costs, which most people know, and then he asks: how much do electricity, gas and water cost? A few know electricity costs, but he’s never had anyone know the cost of gas or water.

Read the full article in ReNew 134.

LED filament globe

New choices in lighting: An LED buyers guide

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The move to LED lighting has become mainstream, with more options appearing constantly. Lance Turner takes a look at what’s available.

For many homes, lighting is one of the most overlooked aspects. Incorrect lighting can make a room unpleasant to be in, or make it more difficult to perform tasks such as reading or cooking. Getting it right can take a bit of effort, and though this guide won’t answer all your questions about lighting design, hopefully it will give you a headstart when thinking about the types of lighting to use and the questions to ask.


With almost all lighting technology moving towards LEDs, this guide focuses on LED bulbs. Even the reasonably efficient technologies such as fluorescent tubes and compact fluorescent lamps are rapidly being replaced by LED lighting. It’s likely that within 10 years, most other light sources will have disappeared in favour of the robustness, longevity and energy efficiency of LEDs.

What is an LED?
LEDs (light emitting diodes) are unlike any other lighting system. They contain no glass tubes or heating filaments, instead using a small piece of semiconductor material (as used in computer chips) that emits light directly when a current is passed through it.

LEDs produce light in a range of colours, without the need for coloured filters; thus, to get white light, a phosphor is used over a blue or UV LED chip, similar to what’s used in a fluorescent tube.

Note that the LED is actually the small light producing element(s) in a light bulb or fitting, but most people now erroneously refer to LEDs as the entire bulb or fitting.

LED specs
There are a number of specifications that are useful to consider when buying LED lights.

Bulb wattage
All light bulbs have a wattage rating, which measures how much power they consume. This is where LEDs have a shining advantage over older, more inefficient technologies. For domestic LED lights, the rating is usually between one and 20 watts, compared to a typical incandescent rating of 25 to 100 watts.

Light output: lumens, LUX and beam angle
Many LED bulbs include an ‘equivalent-to’ wattage rating, showing the wattage of the incandescent bulb that the LED bulb is equivalent to in terms of light output. For example, a six watt LED bulb might be rated as putting out the same amount of light as a 50 watt incandescent.

This ‘equivalent-to’ rating is based on the light output in lumens. The lumen rating of an LED bulb, usually included on the packaging, measures the total light output, relative to the response of the human eye.

For bulbs that are suitable for general room lighting—those with wide beam angles, above 60 degrees, but preferably 90 degrees or more—matching lumens for lumens should give you the result you need. Thus, for these types of lights (these are generally found in the common Edison screw, bayonet or ‘oyster’ fittings), the ‘equivalent-to’ rating should be all you need to determine if the bulb is a suitable replacement.

For directional lights, often known as spot lights, it’s a bit different. These are lights with a smaller beam angle, up to around 60 degrees. Such lights are generally used for task lighting, directed onto a desk or work area. Halogen downlights are an example of these—it’s because of their small beam angle that so many of them were needed to light a room! For these spot lights, small differences in the beam angle can make a big difference in how bright the light appears. Many people have had the experience of buying an LED bulb which was meant to be equivalent to a 50 watt halogen, but found that it appears much less bright. The lumens may have been lower, but more likely the beam angle was narrower, creating a bright light directly under the light but darker patches around it.

Read the full article in ReNew 133.


Downlight transformers: The good, the bad, and the very inefficient

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Not all halogen downlight transformers are created equal when using them with retrofit LED globes. Alfred Howell explains how the wrong transformers can be costing you money.

With the retrofitting of LED downlight bulbs to MR16 halogen fittings, households have seen great efficiency gains and cost savings.
However, if you change your bulbs to low-power LEDs but don’t check the transformers, you may be wasting energy. Many of the older downlight fittings use ferromagnetic (iron core) transformers. While simple, they are inefficient compared to modern electronic replacements. To determine the extent of losses in these transformers I performed some simple testing.


Testing and results
I tested a typical ferromagnetic transformer alongside an Osram Redback electronic transformer. Both transformers were tested, with and without a Brightgreen DR700 retrofit LED globe. A Power-Mate Lite energy meter was used to measure power draw.

Type No globe, or globe blown 10.5W globe fitted

Ferromagnetic 5.34W 18.23W

Electronic 0.38W 13.13W

Savings 4.96W 5.10W

Table 1. Energy consumption of electronic versus ferromagnetic transformers,
with and without a load (globe) fitted.


As can be seen in Table 1, the electronic transformer performs well with or without the globe. While it seems a bit pointless to test a transformer without a globe fitted, it’s actually a good indicator of the efficiency, or otherwise, of each transformer. Compare the electronic transformer’s 0.38 W draw without a globe with the ferromagnetic transformer’s draw of an extra five watts. Indeed, the ferromagnetic transformer uses an extra five watts more than the electronic transformer with or without the globe’s load.

While that doesn’t sound like much, it’s not uncommon to find 20 or more downlights in a home. With all 20 lights on, that would be an extra 100 watts burning a hole in your wallet—or 0.5 kWh if they’re on five hours a day.

Solutions and options
To reduce this energy use, the cheapest option is to swap the ferromagnetic transformers for electronic ones when you retrofit. They are low cost, usually under $15, and available from electrical wholesalers and lighting stores. Alternatively, you could upgrade the halogen fittings to dedicated LED downlight fittings with an incorporated driver.

An even better option is to remove the downlights altogether in places where suitable. Downlights compromise ceiling insulation as they must be uninsulated to prevent the fitting from overheating. Also, many downlights, even LED ones, have a fairly narrow beam angle and so tend to produce pools of light. To get high ambient lighting levels requires a greater total wattage from downlights or a light fitting with a wider dispersion, such as an oyster fitting.

It’s clear that changing the globe as part of an energy saving makeover is only part of the solution. For maximum efficiency and results, the whole lighting system, and how the system is used, needs to be evaluated. This includes behavioural changes such as turning lights off when not in use. With a bit of effort, you will be amazed at the savings that can be realised.

Alfred Howell has years of experience managing complex machines, which he reckons puts him in a terrific position to understand how we can work as part of this complex machine we call Earth.

For more great articles like this buy ReNew 133.

Bundanoon Net Zero Cottage

Small changes, big savings: Low-cost, carbon-neutral housing

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You don’t have to spend up big to get an environmentally friendly home. Glenn and Lee Robinson show us their clean, green cottage based on common-sense principles.

Our aim was to build a home that was a lot more environmentally friendly than the average in Australia. So we did a bit of homework and found that it’s surprisingly simple and economical to build a carbon-neutral house. This article describes what we learnt, how that information was turned into a building and how the house has performed now that we’ve lived in it for 12 months.


The most important discovery was that most of the techniques for creating a high-performance house cost little more than standard building practices. There are lots of small things in a building that, when done a bit differently, add up to a big difference in comfort and energy use (see our ‘20 guidelines’ on the last page).

Finding the right design
Our goal was to minimise dependence on energy from unsustainable sources and create a comfortable, affordable home suitable for occupancy through all stages of life.

We began the design process by making a list of what did and didn’t work in all the buildings we were familiar with, listing the features we would like to incorporate. We set a performance standard of net-zero carbon emissions and a budget of just $250,000 for the complete project, including house, garage and landscaping.

We looked at the options available with local builders, project home companies, prefabs and kit homes but found nothing that came near our specifications. A few prefab companies in Victoria could meet our performance spec but freight costs pushed the price above our budget. The one ‘net-zero’ project home available fell short in the performance stakes. The options were disappointing, but, in a country with the world’s highest per capita carbon emissions, perhaps not surprising.

By default we were left with the only viable option being owner-building, which has ended up working out well. We started out by looking at the history of efficient buildings and which techniques and ideas have stood the test of time, and which haven’t. We really wanted to see if we could avoid over-complication in the design so we researched low-tech ideas that have been proven to work.

We found a lot of good ideas in the layouts of Earthship buildings. They often have excellent room arrangements for maximum sun penetration, but we weren’t fans of all their design principles as they require huge amounts of labour to construct and can overheat and leak.

An excellent resource is the website Build It Solar (, where we found the Montague Urban Homestead, winner of the Massachusetts Zero Energy Challenge. We looked far and wide at hundreds of designs and, to us, this was the most elegantly simple, high-performance, economical design. We used this as the basis of our design, but de-tuned it to match our climate and rearranged the layout to suit our needs.

Read the full article in ReNew 133.


Up to standard: Passive House in Australia

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Designing and building your house to the Passive House Standard in Australia is now a viable option. Architect Fergal White visits a certified Passive House home in Canberra to see the house in action and hear its story from owner and designer Harley Truong.

I approached Harley Truong’s Passive House in Canberra knowing that this freezing cloudy July day would be a real test of the house’s certification. Stepping inside, the building was beautifully warm, with no heating system in use. Truly impressive!


The Passive House Standard dictates (low) maximum energy usage per square metre, both overall and for heating and cooling (see box). It does this by specifying a well-insulated envelope and airtightness that is perhaps unprecedented in Australia, where the building code doesn’t stipulate any level at all.

There are now six certified Passive Houses in Australia, with many more under construction. But that wasn’t the case in 2013 when Harley Truong embarked on his own build, so he made remarkable use of the internet to find his way to successful certification.

Renovation attempt
His family’s journey to find a better way of living began with an attempt to renovate their 40-year-old home in Canberra. The house was draughty with cold floors, constant use of ducted gas heating and mould growing on the windows from condensation, all issues that were affecting the family’s health and bills. Winter bills were often as high as $600 per month.

Harley attempted to thermally improve the house but to little effect. Replacing steel-framed single glazing with double-glazed windows (non thermally broken aluminium) and adding curtains made the condensation worse. Locating a whirlybird on the roof pulled heated internal air through the 30 ceiling downlight holes into the attic. Harley says, “I slowly realised that the home was almost the perfect inverse to what a passive solar designed house should be. It had the main glazed living areas facing south, minimal insulation, high air leakage and no thermal mass.”

So when a large corner site (1020 m²) with no overshadowing came up for sale just down the road, Harley bought it almost instantly. The decision was also quickly made to knock down the poorly sited house on the block, and build two homes, one to live in, and one as an investment property.

Read the full article in ReNew 133.


Comfortably ahead – A tale of two heaters

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Turn on your air conditioner—and knock hundreds of dollars off your heating bill. Tim Forcey describes the learnings (and savings) gained from his experiment with reverse-cycle electric heating.


Over the last 20 years my wife and I have raised a family in our 100-year-old Melbourne bayside weatherboard home. Last spring, following our third partial renovation, we installed two air conditioners in preparation for the hot summers to come—particularly so my wife and I could stay comfortable when working at home.

The two air conditioners we chose did just that, easily cooling our full ground-floor living space (128 m2 consisting of seven rooms and a hallway). Based on advice from Matthew Wright (founder of, we opted for two top-of-the-line Ururu Sararas (US7s) manufactured by Daikin: one small wall-mounted unit in our front bedroom (2.5 kW rated for cooling) and one medium unit (3.5 kW) in the lounge room.

The total US7 rated cooling capacity of 6 kW contrasts with a 14 kW multi-headed unit that the salesperson said we would need. So lesson number one: avoid the up-sell if your house is reasonably well-shaded and insulated (see box for more on sizing).

Come winter, I was keen to learn how these reverse-cycle units would compare with our 20-year-old ducted gas heater in terms of health, comfort, convenience and operating cost, particularly following on from research by Beyond Zero Emissions and the ATA (ReNew’s publisher) into the potential for economic and environmental benefits from going off gas.

My findings? There were pluses and minuses when comparing the two heating methods on comfort and convenience. But when it comes to cost, the reverse-cycle air conditioners beat ducted gas hands down—not only for our home, but possibly for hundreds of thousands of homes around Australia.

Science—sort of—in the home
Starting in late June 2015 (mid-winter), I sought to heat our home on alternate days using the US7s and then ducted gas.

The US7s are heavily instrumented and can tell you the outdoor temperature, the indoor temperature, the indoor humidity and how much electrical energy they have consumed since you turned them on today, or since you installed them last year! Adding to this, I spread thermometers throughout our living areas. I also referred to our in-home electricity display that relays instantaneous electricity-use figures for our whole house from our smart electricity meter.

And for the first time in my life, often wearing a bathrobe and head torch, I journeyed out behind the bushes to the not-so-smart gas meter to diligently record gas usage.

I will not claim that this exercise was the best example of the scientific method we have seen. Variables and shortcomings had to be managed, such as failure to focus on the task-at-hand at 5.30 am before the morning coffee, Daikin’s less-than-fully-illuminating owner’s manual, and my co-occupants.

Read the full article in ReNew 133.


Cooking Challenge: ReNew enters the kitchen

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For our recent cooking challenge, we asked ReNew readers how they’re reducing their energy use in the kitchen. In true ReNew fashion, we got entries addressing the problem from a range of DIY angles.

As Alan Pears highlighted in ReNew 130, while the kitchen is a small part of energy use in the full food system, it can be a significant part of household energy use, particularly for low-energy-use households. From improving our understanding of the energy efficiency of appliances and cooking techniques to improving the insulation in saucepans, Alan presented a range of things to think about when you get into the kitchen.


The entries in our competition reflected that. Several tackled the topic by looking at equipment, with pressure cookers, solar ovens and haybox cooking featuring. Several looked at techniques, such as not cooking with a half-empty oven, defrosting food in the fridge (or on the bench) and even cooking multiple things in a stack of pots, to use the escaping heat.

And the winner is…
The ATA crew particularly like Jan Heskes’s entry, making that our winner: it’s a practical, simple approach to reducing energy use. We’ve included the winning entry in full, along with parts of several other entries that reflect the range of responses. Jan wins a GoalZero portable solar USB charger kindly donated by Laughing Mind and valued at $169.

Never cook with a half-empty oven
Jan Heskes

Much as we would like to, we cannot always afford to have the latest energy-efficient appliances in our home. However, by using what we do have more thoughtfully, we are still able to significantly reduce our energy consumption.

Our kitchen contains a standard-sized stove with a fan-forced electric oven and gas cooktop. The stove is a few years old and would have been energy efficient for its time. Before turning on the oven I plan and prepare as many dishes as possible to bake while the oven is heated. Surplus food produced is stored in the freezer for future meals. The freezer is also used efficiently by avoiding operating partially empty. With ongoing planning, food is defrosted passively and reheated either quickly in the microwave or, if possible, in conjunction with accompanying dishes. As a result the oven is generally only used about once a week in our house even though nearly all of the food we consume is homemade.

Read the full article in ReNew 132.

Three options of hot water plumbing: gas-boosted solar, full gas and solar only.

Farming Renewably: Reaping the benefits

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One person/farm can make a difference: David Hamilton describes how his farm’s sustainable conversion cut carbon, benefited the landscape and turned a profit.


I’ve read many inspiring articles in ReNew from individuals trying to live more sustainably and lessen their impact on the planet. This article takes a slightly different approach–a rural perspective–to demonstrate that it can be commercially viable to run a farming enterprise using systems that are truly renewable, whether that’s for water, electricity, housing, food, livestock, pasture or wildlife.

Our journey to sustainable farming began in 1993, when my wife Roberta and I purchased a 60-acre property in the south-west of WA with the twin objectives of restoring the degraded land and becoming as self-reliant as possible. The land included pasture that was totally lifeless and neglected, along with a dam, two winter streams, old gravel pits and two areas of magnificent remnant native forest. We wanted to be independent for water, electricity and as much of our food as was practical. Withe fewer bills to pay, we could work fewer hours off the farm–which was very appealing.

As a registered nurse with no farming experience, I was on a vertical learnign curve. Luckily, Roberta has a dairy farming background and, with her accounting experience, is a wizard at making a dollar go a long way.

When we began, we were both working full-time. We spent the first two years establishing a gravity-fed water supply, preparing the hosue and shed sites, and fencing the property, including to protect remnant bush from planned livestock. We also planted over a thousand native trees and shrubs, plus a few ‘feral’ trees for their air conditioning and fire-retardant properties.

Read the full article in ReNew 132.



Emerging materials

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The world of building materials is ever-evolving, but which of the new materials will make it to market acceptance? Lance Turner looks at some of the products starting to take off now, and what’s just over the horizon.

Solar panels: the new building material?
Solar panels can take the place of some building materials, known as building integrated photovoltaics (BIPVs). For example, they may be integrated into the roof, replacing roofing sheets or tiles, they may form the roof of a carport or verandah (as on the cover of the last ReNew!) or they can even be part of a wall or balcony rail. Anywhere a surface gets a good amount of sun is an opportunity to use BIPVs.


Although BIPVs sound like a great idea, reducing costs by displacing some building materials while producing a neater, integrated look, they have struggled to gain a foothold in Australia. There are some amazing examples overseas, but the examples here are far more limited. And, unfortunately several manufacturers, such as Schott Solar, have stopped manufacturing them in recent years due to the low cost of standard panels.

However, there are still options available, mostly in the form of roof materials. The original PV Solar Tiles ( have been available for more than a decade, and roofing manufacturers are now getting in on the act, with BIPV systems available from Monier (SOLARtile, see, SolTech (not available in Australia as far as we know, see, Nulok (, Tractile ( and Stratco Solatop (

The roof is not the only place where BIPVs are being used: it’s also possible to install windows that actually generate electricity. This has the added benefit that the windows reduce the incoming energy and so help keep the building cool. The main disadvantage of a PV window is the higher cost should a breakage occur. They’ll also reduce solar gain in winter, thus reducing warmth collected passively.

So what’s currently available in the solar window arena? A few years ago there were several options, but those manufacturers have either stopped manufacturing them or have disappeared. Maybe they were a little too far ahead of the curve or the high manufacturing costs just didn’t add up.

As always though, technology advances and a new breed of lower cost dye-based solar cells are emerging that may change the way we look at windows.

Read the full article in ReNew 132.


Mass effect: The messy realities of mass

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Mass in buildings can help moderate internal temperatures, but it can also be tricky to control its effects. Alan Pears examines when and where mass works well—and when it doesn’t.

The way buildings work is very complicated. That’s why designers increasingly use computer models that simulate hourly performance over a year to try to deliver good performance. Even that has its challenges! Adding mass to a building is no exception; it can bring significant benefits—and some problems.


This article is an attempt to explore the role of mass in buildings and suggest some paths forward for building owners and designers.

First, ‘mass’ is not actually what we want. The beneficial feature of mass is that it increases the heat storage capacity of a building so that, for a given amount of heat input or loss, the change in temperature inside the building is reduced. This outcome can be achieved by using a lot of material (mass), materials with a high heat capacity per unit of mass (e.g. water can store about twice as much heat per cubic metre as concrete for the same temperature rise in the material), or by storing energy as ‘latent heat’ in what are known as phase change materials (PCMs, see more on these later).

High mass buildings tend to sit close to the 24-hour average temperature for the time of year, because it takes a lot of energy to shift the temperature of a heavy building. In much of Australia, especially when 24-hour average temperatures are 18 to 24°C, this means the building tends to be closer to a comfortable temperature more of the time.

Thick, heavy walls slow down the rate of heat transfer into or out of a building, as the ‘wave’ of heat has to work its way through the thick material. This can delay the heat flow until it cools down (or heats up) outside, reducing heating or cooling energy.

But it can have a downside. I once lived in a house with a west-facing uninsulated cavity brick bedroom wall. It would delay the heat flow from the afternoon sun until after bedtime, so I would cook at night unless the outdoor temperature had cooled enough for me to flush out the heat.

Note that mass does not provide better insulation—but under varying temperature conditions it can have a similar impact on energy use to a small amount of insulation. Confused? Let’s look at what this all means in practice.

Read the full article in ReNew 132.


Bricks, blocks and panels: What’s in a wall?

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There are many different approaches used for building the walls of a home, but which one is ideal for your build? Lance Turner takes us on a quick tour of the different systems, materials and their sustainability credentials.

For those embarking on a sustainable building project, there can be almost too much information available, making it hard to quickly compare the possible building approaches. One important decision is the wall-building system to use in your build.


To help in that evaluation process, this article provides a quick guide to the different wall-building systems and materials available. For each system, we consider how the walls are constructed, their thermal performance and sustainability. A table at the end of the article summarises each approach in terms of a range of sustainability criteria. It’s intended as a quick guide; you’ll need more information before you start your build, but we hope to give you a head start on the different systems available.

So, what is in a wall? There are many different methods of wall building, but they all fall into four broad categories—stud frame with cladding, bricks/blocks, cast/poured materials and pre-fabricated panels.

Stud frame with cladding
Probably the most common wall system used in Australia is a structural timber frame with cladding, in either a single or double timber stud system.

Single stud walls have one layer of framing—the internal cladding (such as plasterboard) is attached to the inside of the frame and the external cladding (such as weatherboard, fibre-cement or brick, as used in brick veneer, see later) is attached to the outside. Bulk insulation is fitted into the spaces between the studs of the frame, and foil insulation can be added as an additional layer around the outside of the frame, allowing for R-values up to almost R 4 with the right material combination. For example, according to the TasTimber document R-values for timber framed building elements —walls (, a 90 mm stud wall with R 1.5 batts, reflective foil layer and AAC external cladding can achieve an R-value of 3.9.

To enable even more insulation, a double stud wall can be used. Double stud walls are just like two single stud frames, built one beside the other with a small gap in between. The resulting walls can be 200 mm or more in depth, so a great deal of bulk insulation can be installed. Of course, a double stud wall costs more than a single stud wall, but its advantages may well offset the extra cost if you live in an alpine area or area with low average temperatures, such as north-west Tasmania.

For a truly thermally efficient home, thermal breaks (thin layers of insulation material) between the studs and external wall cladding should be considered, although the extra expense may not be justifiable in moderate climates where low levels of heating and cooling are required.

Read the full article in ReNew 132.


Many hands make light work

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Can a collaborative approach to building design lead to even better sustainability outcomes? Eugenie Stockmann describes a different type of development via The Green Swing.

When setting up The Green Swing in 2010 to develop a plot of land in inner-urban Perth, we wanted to create a distinctly different type of housing development—one that would be sustainable, affordable and with a great community feel. After all, we were planning to live in it ourselves!


The Green Swing is what we called our development company, a partnership of myself, my partner Helmuth and another couple, Alana and Mark Dowley. That first project, Genesis, was completed in 2012 and is now home to the four of us, alongside two other apartment homes. Pleasingly, it went on to win several industry awards.

We learnt a lot along the way; perhaps most importantly, we realised we didn’t want to let all that knowledge and experience just fade away. So it wasn’t long before we commenced our second project, The Siding, due for completion in early 2016.

Oversights and inconveniences
We also learnt that there’s always room for improvement. One area we were particularly keen to improve was the process of collaboration.

You might think that all buildings are designed and constructed via collaboration. After all, it’s very hard for one person to design and build a house completely by themselves. Even the early stages of a project involve a number of people—the client, architect or building designer, draftsperson, engineer, planner and building surveyor, just to name a few.

Yet, the experience of our first project highlighted that effective and meaningful collaboration doesn’t always come easy. With so many people involved, it perhaps comes as no surprise that problems, inconveniences and oversights often occur, resulting in head-scratching exclamations such as, “Why did they do that?” or “If only they’d asked before they did…” and “This could have been easily avoided if…”—you get the picture.

To add to the issues, people’s idea of and commitment to sustainable building design and construction can vary. The Australian Public Service (2007) described sustainability as a complex, ‘wicked’ issue, in that no-one knows what it looks like, nor how to get there. Somewhat ironically, their conclusion was that a collaborative approach is best for dealing with wicked problems!

Read the full article in ReNew 132.


Low cost solar heating: Using free heat from your roof

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After reading an article in ReNew, Alan Cotterill decided to design a closed loop heat exchange system to supplement his home’s heating with free heat from the roof. A couple of iterations later, he describes the resulting effective system.

In early 2014 I commenced efforts to use the heat from our roof cavity to contribute to winter heating. I decided on a closed loop system, which would take in room air, duct it through the roof and return it to the house at a higher temperature. A closed loop system avoids the issue of drawing down insulation fibres and dust from the roof cavity.


Useful attic temperatures
My home combined with our very cold but sunny winter days in Wagga seemed especially suitable for this system to run with reasonable efficiency. The house has a grey Colorbond steel roof and a large roof area relative to the internal floorplan, due to a high pitched roof and the wide verandahs and garage being included under the main roof structure. The east-west orientation of the long axis of the house and the north-facing roof area being covered with solar panels have not prevented useful attic temperatures. Measured 60 cm below the peak of the roof cavity, the average maximum attic temperature was 28 °C for the two weeks starting 16 July 2014 and 37.8 °C for the two weeks from 19 August 2014.

A first attempt
My first prototype forced room air through a system of ducts in the roof using a centrifugal exhaust fan mounted on its side on a shelf in the laundry. The air was distributed to three 12-metre runs of 100 mm flexible aluminium ducting before returning the air to the house. The returned air was reasonably heated but the total volume of returned air was inadequate to contribute significantly to winter heating.

Read the full article in ReNew 132.

home assessments

100 home energy efficiency assessments

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Simple discussions with householders can shine a light on common energy efficiency problems. Tim Forcey shares the process and lessons learnt in a recent round of council-funded home energy assessments.

In late 2014, a local council in eastern Melbourne committed to deliver 100 home energy assessments as part of a sustainability outreach program. They contracted Positive Charge—a social enterprise set up by Moreland Energy Foundation Ltd—to do the assessments over a six-week period, and I was one of the two assessors. It was interesting to observe which residents took up the offer, what they needed help with, and to consider how effective the assessments were. This article is an attempt to share what we learnt.


Over 90,000 people live in the council area where this project took place, so 100 free consultations were not going to change the world, but perhaps would be a step to something bigger.

Such home energy assessments have been done for many years in many ways. Some have been done informally by volunteers— neighbours helping neighbours. Some have been done within the strict requirements set by federal, state or local governments. Some have been done at no cost to the resident, while others have involved thermal imaging cameras and blower doors and cost more than $400. Some energy retailers have trained up assessors and then pulled the plug on the whole thing without a single assessment being delivered.

Getting the word out

This service was offered at no charge to residents, but council advertisements noted that assessments were “valued at $250”. Residents were informed about it via council newsletters, notices in the local paper, flyers sent out by politicians in the lead-up to the Victorian state election and a stall and ad hoc spruiking at a local community festival. When residents responded with a phone call to Positive Charge, a member of the team scheduled a one-hour assessment.

The process

One thing we learned fairly quickly was that we shouldn’t call them ‘assessments’; ’consultations’ would be more acceptable (and more accurate). As I walked through a client’s front door, they immediately asked me, a bit defensively, “So, what are you going to assess?” To which I replied, “Nothing! Let’s talk about whatever you want to talk about.”

Upon arrival at a client’s residence, I’d first locate a table where we could work, with enough room for my binder full of photos, reference materials and fact sheets. I’d then ask the homeowner or tenant what they wanted to discuss. During the booking phone call, Positive Charge staff had usually tried to

gather some of this information, so residents were already focused on what they wanted to achieve from the consultation.

I would then write down what the resident was saying, for my own use over the course of the hour. Next, I would ask the resident to also grab a pen and a paper so they could take notes or jot down ideas. The aim of the hour was simply to come up with some ideas and actions in a loosely prioritised list, rather than there being an official follow-up report.

Sometimes what they wanted was about ‘bang for the buck’. For some, it was about improving their desperately uncomfortable homes; achieving positive environmental outcomes was usually in the mix as well.

Next, I would have a quick squiz around the home, asking things like, “How is the house on a cold winter day, or during summer heat waves?” We would check out the space heating and cooling systems, their means of water heating, how many fridges were hiding in the garage, the extent of window treatments, the style of lighting, the air-tightness of the house and so on. Then, back to the table—a quick look at gas and electricity bills—and then it was time to start the list!

Read the full article in ReNew 131.


IMG_4484 400px

Off-grid EV charging

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From off-grid electric vehicle (EV) charging to a desire for more sustainable transport, EV owners share the stories behind their choices with Robyn Deed.

Until recently, number one on Ross Ulman’s ‘bucket list’ was owning an EV and charging it from the sun (a ReNew kind of bucket list!). He got to tick off that item late last year after buying a secondhand Nissan Leaf, with 10,000 km on the clock, around the same time as he and his wife Vivienne moved to their new energy-efficient off-grid home near Daylesford.


He bought the Leaf from a friend who was upgrading to a larger EV, a Mitsubishi Outlander, which, with its ‘range extending’ petrol engine meant the friend could do without a second fossil-fuelled car. Pure EVs are probably uncommon in the country, says Ross, because of the longer distances travelled and the resulting ‘range anxiety’. Range doesn’t cause Ross problems, however. He plans ahead for his longest trip, about 90 km return to Ballarat for work, which is well within the 120 km range of his fully charged Leaf (the quoted range is 170 km, but he finds he only gets about 120 km with the hilly driving around Daylesford). His main driving is into and around Daylesford, about 15 km, all easily doable without mid-trip recharging.

He doesn’t drive the Leaf for his occasional trips to Melbourne, though driving there from Daylesford would be no problem, and charging in Melbourne would be no problem also, as there are charging stations in the city. However, the trip back to Daylesford would be problematic as, even if leaving Melbourne with full charge, the Leaf would need a further charge, albeit a short one, on the journey home—the increase in altitude uses more power than the downhill run into Melbourne. Ross is planning to upgrade in a couple of years, when a Leaf with double the range is slated to become available. He hopes that affordable EVs with double or triple the range of the current Leaf will make them more mainstream. And leadership from government is also needed. “EVs are the future of the car industry,” he says, “but we really need strong public policy with incentives and infrastructure investment.”

One interesting aspect of Ross’s EV is that it’s charged off-grid. He only charges the EV during the day when the sun is shining, a bit different from the usual overnight charging regime. The off-grid system, designed by Off-Grid Energy Australia, is AC-coupled, which Ross says has been fantastic, enabling him to charge the EV at the same time as the house batteries are charged: any draw from the house or car comes direct from the solar panels (when they’re producing energy), rather than from the house battery, reducing battery cycling.

The solar PV system is oversized (10.5 kW solar and 40 kWh batteries), which the system designers say should be sufficient to charge both the house batteries and the car even on cloudy days. So far (they’ve had the system since November 2014) there have been a couple of runs of four or five cloudy days and sufficient energy has indeed been generated.

Ross plans to work around his solar system production to avoid over-discharge of the batteries. If there’s a run of rainy days, he won’t charge the Leaf: if it has enough remaining charge he’ll drive it short distances; and, if it hasn’t, then he’ll make alternative transport arrangements, such as using their petrol vehicle or public transport. So what’s next for Ross’s bucket list? Well, there’s that Leaf upgrade in a couple of years. Or perhaps it’s just time to settle back and enjoy demonstrating that off-grid and EV can go together.

Read more stories about EV ownership in Best EVer stories: Electric vehicle owners share the love in ReNew 131.

cool mob

COOLmob: Smart cooling in the tropics

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With cooling the biggest contributor to household energy use in the tropics, an innovative new project is finding smart, simple ways to change that. Jessica Steinborner from COOLmob explains.

This time of year in Darwin sees two things rising to uncomfortable levels: temperatures and power bills.


The onset of the hot, wet season leads people to seek relief indoors with the aid of air conditioners, with a consequent spike in their energy consumption and bills, particularly an issue for those on low incomes.

But a program currently being rolled out in the Top End is aiming to change that. The message, and practice, of the program is that keeping cool in the tropics doesn’t have to mean the household budget taking a hit.

Smart Cooling in the Tropics, funded by the federal government’s Low Income Energy Efficiency Program (LIEEP), is helping people keep cool while keeping costs to a minimum.

Its focus is on educating and assisting people to use a range of strategies to make their living spaces cooler. This includes getting maximum efficiency from their cooling devices and making their homes easier places to keep cool.

The program, which began in March this year, is being delivered by COOLmob, a Darwin-based program run by the Environment Centre Northern Territory that promotes energy efficiency and other aspects of sustainable living.

A three-pronged approach

Each Smart Cooling participant receives an energy-use assessment from a visiting trained COOLmob officer. The outcome of this assessment determines the type of treatment. The project focuses on three things: energy literacy, effective use of appliances and appliance upgrades, and retrofits that improve the thermal performance of the building.

Energy literacy promotes simple, practical actions such as understanding electricity consumption and bills, setting timers and thermostats on air conditioners to reduce electricity use, and making use of prevailing breezes.

The appliance upgrade service can provide pedestal and floor fans, to encourage less energy-intensive cooling systems. It can also retrofit devices such as a thermostat controller to older air conditioners, clean air conditioners to make them more efficient and seal up poorly installed box air conditioners to improve their efficiency.

The third aspect of the program is helping people make modifications to improve the thermal performance of the building structure. This can be achieved, for example, by installing shading around external walls and hot windows, painting roofs with heatreflective paint and improving air flow in roof cavities.

Targeting low-income households

So far 100 householders in the greater Darwin region have signed up to the project, from a target of 480. These householders were recruited under the program’s eligibility criteria, which target people living on low incomes. Darwin is notorious for its high cost of living so savings on household expenses are particularly relevant.

Finding out what works

An important aspect of the project is collecting data about energy use for cooling, and the impact of the project activities on energy consumption and thermal comfort. The results of the Smart Cooling project are being analysed and evaluated by researchers “This is one of the first large-scale projects solely concerned with identifying the best approaches to cooling and energy efficiency in tropical Australia.” at Charles Darwin University’s Research Institute for Environment and Livelihoods.

This is one of the first large-scale projects solely concerned with identifying the best approaches to cooling and energy efficiency in tropical Australia. Its outcomes stand to be used to inform national energy policy and to influence the development and modification of building codes and other rating systems to make them appropriate for Australia’s tropics.

The research will consider a range of factors including which changes produced the biggest energy cost savings, which households achieved improvements in household comfort levels, and which participants gained better awareness of energy consumption issues and opportunities.

Charles Darwin University is one of five partners helping COOLmob deliver the Smart Cooling project.

The other partners provide links to the communities targeted by the project. They include local organisations representing seniors, urban Indigenous and refugee communities, and people working as carers or care recipients.

Not sacrificing comfort

The project also has an emphasis on creating comfortable living spaces appropriate to the climate. The message is not about sacrificing comfort by using cooling appliances less to save money. Smart Cooling argues that you can manage your electricity bills while still maintaining a comfortably cool home.

Although the project specifically targets low-income households, other Darwin residents have been seeking advice on cutting their cooling costs. So COOLmob is offering energy use assessments on a pay-for-service basis for people outside the project’s eligibility criteria.

It’s early days yet, but there are promising trends. So far there’s been a strong indication that participants are motivated to use less energy and have made attempts to do so already. Stay tuned for more on the results!

Jessica Steinborner is acting COOLMob manager at the Environment Centre NT. For more information on the COOLmob program, visit or call (08) 8981 2532.

Read the full article in ReNew 130, including COOLmob case studies and home cooling tips.

This trough collector sits on the Charlestown Square Shopping Centre in Newcastle, NSW, as part of a solar cooling system installed in 2010.

The state of solar cooling

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It’s the holy grail of cooling—using the sun to power your cooling system. Mike Dennis from ANU takes us on a tour of where the solar cooling market is now and where it’s headed.


Most Australian homes are now equipped with some kind of air conditioner, but their rise in popularity over the last decade has put substantial pressure on the electricity transmission and distribution network—and the required investment in ‘poles and wires’ has been blamed for recent spikes in retail electricity bills.

Some electricity retailers charge a premium for grid electricity drawn during afternoon periods when air conditioning may be in use, but offer a paltry sum in return for photovoltaic power supplied to the grid during the same period. One NSW retailer charges over 50c/kWh between 2 pm and 8 pm on weekdays while offering only 6c/kWh in return for net photovoltaic energy exported to the grid.

Water heating and air conditioning are usually the two main energy sinks in a residence. To some extent, water heating may be time-shifted to avoid exposure to peak tariffs, but air conditioning load offers less flexibility. What can be done about this?

The first consideration, of course, should be to try to reduce or eliminate the need for active air conditioning. A well-designed building with appropriate shading, insulation and thermal mass is a good start. Secondly, householders should explore opportunities for passive air conditioning using prevailing breezes and carefully designed cross and stack ventilation.

As a last resort, a householder may decide to install an electric air conditioning system. These devices are intoxicatingly effective in providing comfort with convenience and immediacy. The shopfloor price may not be as confronting as the first electricity bill, however!

So, how can householders sidestep peak electricity charges and be comfortable in their homes at the same time?

Active air conditioning options that minimise environmental impact 


The obvious option is to install a photovoltaic (PV) system to drive a regular air conditioner. Several companies offer packages to do this directly, or it can simply mean installing a larger PV system to run the whole house (‘Solar cooling options available now‘ also in this issue).

However, electrical supply will be required late in the afternoon and into the evening to offer proper service during summer cooling and winter heating periods.

It is worth noting that peak summer cooling loads often occur late in the afternoon, while peak solar is at noon. In winter, peak heating loads are in the evening.

Hence, backup will be required in the form of either a grid connection or a local electricity storage device. Both of these options come at a price. It is likely that future electricity storage prices will make this option viable. No doubt someone will produce a simple Sunulator-type calculator to size the PV collector and battery bank for such purposes. [Ed note: Adding batteries is planned for the next phase of Sunulator development!]

Read the full article in ReNew 130.

This trough collector sits on the Charlestown Square Shopping Centre in Newcastle, NSW, as part of a solar cooling system installed in 2010.

Solar cooling options available to households now

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Solar cooling is possible at home writes Lance Turner.


Solar cooling is perfectly achievable for homes and businesses using off-the-shelf technology. The simplest system, and the lowest cost to install, uses high-efficiency heat pumps (reverse-cycle air conditioners), which can have EERs (energy efficiency ratios) of up to 5.7 for the smaller models, combined with a grid-interactive solar power system. By running the heat pumps during the day, when the solar system is producing the most electricity, the heat pumps are, effectively, completely solar powered.

There are other cooling system types that can also be run directly from solar-generated electricity, with evaporative cooling systems being the most common. However, most common evaporative coolers use a simple system of passing air through wet filter pads, known as direct cooling. While this does cool the air somewhat, it also increases the humidity of the air, something often undesirable in hot weather.

Other options in the pipeline 

An alternative system, the Climate Wizard (a domestic model will be available in 12 to 18 months), is an indirect evaporative cooler that uses a counter-flow heat exchanger to cool the air without adding moisture. The system uses a heat exchanger, which has both dry and wet channels isolated from each other, to keep the evaporating water and the airflow into the house separate. Air passes through the dry channels in the heat exchanger, while some of that air passes back through the heat exchanger via the wet channels, where evaporative cooling removes heat. This cools the air in the dry channels without adding moisture. The dry air then flows into the home, while the moist air is expelled outside. Seeley International, the supplier of the system, claims that this system results in cooler and drier air entering the home compared to a conventional evaporative cooler, and can provide cooling performance similar to a heat pump air conditioner, with lower energy use.

While not common in Australia, there is a combined solar heating and cooling system known as a Combi+ system. It uses a solar ‘combi’ system (which uses solar thermal collectors, backed up by another heat source, to provide both space heating and hot water) combined with a sorption chiller for summer cooling. Combi systems are common in countries such as Austria, Switzerland, Denmark, Sweden and Norway, although Combi+ systems are less so, due to the lower cooling requirements in much of Europe.

PV-powered economics 

CSIRO has recently conducted research into the economics of PV-powered air conditioners. As presented at All Energy Expo 2014, their provisional results demonstrate that using PV to power the whole house, including the air conditioner, has a much better return on investment than using the PV to power only the cooling system. Systems with batteries could become cost-effective as battery prices decrease. The research is being published soon; watch out for it on their website.

Read The State of Solar Cooling in ReNew 130 for a look at the solar cooling market.

greeny flat

The Greeny Flat experiment

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Andy Lemann shares the principles, materials, results and lessons learnt in building a low-cost, high-efficiency home. Seven months into a one-year trial, the outcomes are promising.


For me, learning to live in harmony with the planet means learning to live without fossil fuels. Before I’m accused of gross hypocrisy, let me be the first to admit that my way of life is highly unsustainable: I drive a car, I eat food grown in faraway places, I use fossil fuels. I certainly don’t have all the answers, I’m simply attempting to take the first steps towards a fossil-fuel-free future. That is what the Greeny Flat is all about.

The Greeny Flat is a full-scale living experiment currently underway on a quiet street in Mittagong in the Southern Highlands of NSW. We’re aiming to see if it’s possible to build a small, comfortable, healthy, energy-positive, low-maintenance, fire-resistant, water-efficient, elderly-friendly infill house at an affordable price. Our two primary aims were to make it energy-positive and affordable.

For 20 years I designed and built sustainable houses in the Rocky Mountains of Montana, near the Canadian border, where the winters get down to -40 °C and the summers up to +40 °C. In that climate, attempting to come even close to net zero energy building is a huge challenge. When I returned home to the NSW Southern Highlands a couple of years ago, it occurred to me that building an energy-positive home here should be relatively easy and inexpensive.

I have since learnt that the cost of most things in Australia is much higher than in the States, so making the Greeny Flat affordable has, in fact, proved to be our biggest challenge. Meanwhile, my partner Cintia and I have lived in the house for nearly seven months, closely monitoring its energy performance, water usage, indoor air quality and comfort levels to see whether it actually meets the initial goals.

The perfect site 

The Greeny Flat is designed to meet the future needs of my aging parents who, in their infinite wisdom, had found and purchased an excellent site over 20 years ago. There’s an existing fibro cottage on the east half of the lot that they rent out, which left the west half available for us to build the Greeny Flat.

It is the perfect site for a passive solar home with a gentle slope to the north-east, nice views to the north, and existing buildings and trees to the west and south providing protection from cold winter and hot summer winds. The excellent solar access is also protected by the street to the north, which means that no neighbour can build or plant anything to block our sun in the future.

Just as importantly, this is an infill site in an already-developed area. This helps to reduce sprawl, preserve open space, agricultural land and natural habitats, maximise use of existing infrastructure, and reduce driving.

Read the full article in ReNew 130.


ATA research: Are we still cooking with gas?

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Gas report author Kate Leslie gives the lowdown on the research and its findings.


The Alternative Technology Association (ATA), has just launched a report that considers the economic implications of projected retail gas price rises on households, and asks whether there are efficient electric alternatives that are more cost-effective.

Funded by the Consumer Advocacy Panel, the research aims to identify those locations and household types that may benefit from a switch from gas to efficient electric appliance use—or from staying off the gas network in the first place (in the case of new homes or existing all-electric homes). The research also separately analysed the environmental impact of these potential switching decisions.

Much of the emphasis in the gas debate to date (which has been largely dominated by industry) has been on increasing gas production, as opposed to considering potential changes in demand. ATA’s research asks whether increasing gas production is the most cost-effective, efficient and sustainable approach.

Gas price rises are already an important issue for residential consumers; according to the Victorian Council of Social Services, “Household gas prices have risen 33% in real terms since 2008–09, largely unnoticed because all the attention has been on the more rapid growth in electricity prices over the same period (53%).” (

Analysts vary on how much gas prices will rise over the next 5 to 10 years, but all agree that more rises are coming.

So what are the alternatives? 

Gas is typically used in homes for space heating, water heating and/or cooking. Over the last few years, efficient electric alternatives for all these end uses have become available. The most cost-effective, efficient electric alternatives chosen for the research were:

  • heat pump reverse-cycle air conditioners— for space heating
  • heat pump hot water systems—for water heating
  • induction cooktops and efficient electric ovens—for cooking.


The research considered the economic case for replacing gas appliances with electric options in a range of different ‘gas zones’, for a range of different house types and under a range of different ‘replacement cases’.

Replacement cases include whether or not the house is currently gas connected, the number and type of gas appliances to be switched, and whether existing gas appliances are close to the end of their life (i.e. due to be replaced within five years).

Figure 1 shows the 26 gas pricing zones modelled. The variety of zones meant that the research could take into account the different gas prices and pricing structures that exist across locations, as well as the different space/ water heating end-use needs by climate zone; Table 1 shows the heating load assumed per climate location.

The research also modelled six different household types, ranging from small to large existing homes (all assumed to have R2.5 ceiling insulation), a typical public housing home (taking into account relevant energy concessions), and a new 6 Star home (see Table 2). This enabled analysis of households with different space and water heating requirements as well as cooking energy use.


For new homes, and for existing homes that don’t currently have gas, the research found a strong and consistent result: in all gas and climate zones across the five states and one territory modelled, it is more cost-effective to go all-electric than to connect to gas. This holds as long as efficient electric appliances are able to be used (acknowledging the fact that space or building configuration constraints, such as in apartments, may mean that efficient electric appliances can’t be installed).

For existing homes already connected to gas, the situation is more complex. Whether it’s cost-effective to switch from gas to electric appliances depends on a range of factors including the age of the appliance, the climate zone, whether it’s the last gas appliance (so replacing it means the customer can disconnect from gas and avoid the fixed service charge, in the order of $250 to $300 per year) and whether the customer is on mains or more expensive bottled gas.

Tariffs also come into the equation, including the ratio of gas to electricity prices, and the fact that many customers are on a declining block tariff—meaning that higher gas usage is, in effect, rewarded by lower prices.

Specific appliances and climate zones 

For existing homes connected to gas, there were some clear findings for specific appliances and climate zones.

Of the three end uses modelled, space heating was consistently the most cost-effective to switch from gas to efficient electric.

In warmer climate regions (including SA, Queensland and some parts of NSW), switching all gas appliances to efficient electric ones and disconnecting from the gas network offers better economic returns than in cooler climates—partly due to the improved performance of heat pump systems in warmer climates, and also partly to the correlation with higher gas prices in those regions.

Heat pump hot water systems were found to be more cost-effective than gas hot water systems where gas prices are relatively high compared to electricity prices; or where the climate is warmer (and so the systems perform more efficiently). Gas hot water systems are more cost-effective in most other locations.

Switching from gas to an induction cooktop and electric oven was found to be cost-effective when combined with disconnecting from the gas network (and thus avoiding the gas fixed charge).

The effect of gas prices 

The modelling results were not particularly sensitive to retail gas price trajectories of between +5% and +50% from today (in real terms). The research found that the impact of that range of future gas prices on any individual economic case isn’t as significant as the relative cost of gas versus electricity in each gas pricing zone; and the relative energy use of gas versus electric appliances.

The report notes, “In only a small number of gas zones and for a small number of household scenarios/replacement cases does the economic proposition for switching fuels change from negative to positive over 10 years on the basis of different gas price trajectories.”

In the majority of Victorian gas zones, where switching was often uneconomic, consumption charges for gas are approximately a fifth of the price of electricity charges on an equivalent energy basis. In parts of NSW and Queensland, where a significant number of economic switching cases were found, gas prices are higher relative to electricity prices— up to around half the cost of electricity.

A positive result for emissions 

Although the research was primarily concerned with economics, the ATA considered it was also important to determine the greenhouse gas impact of switching from gas to electric appliances. The findings were mostly positive: homes using natural gas for all three end uses will reduce emissions if they switch entirely to efficient electric appliances, regardless of home type or location.

Taken individually, switching to electric space heating has the clearest positive impact especially for the colder locations. Results for hot water are less clear—switching from gas storage to heat pump hot water systems may result in slightly higher emissions in ACT and Melbourne. Efficient electric cooking increases greenhouse gas emissions in all locations except Tasmania. However cooking emissions are very small compared to the other uses.

These estimates are influenced by the cleanliness of generation in your state’s electricity grid. Victoria’s continued reliance on brown coal results in high emissions, while Tasmania and South Australia’s emissions are lower thanks to their use of hydroelectric and wind generation respectively. Future increases in grid-connected renewable energy (including rooftop solar) will make electric appliances cleaner to run. Households also have the option to offset their emissions, for example via ATA’s Community Climate Chest or a GreenPower plan from their energy retailer.

Data on the climate impact of natural gas is scarce. In addition to the carbon dioxide emitted when gas is burned in the appliance, some natural gas leaks unburnt into the atmosphere from wells, pipelines etc. Even though these ‘fugitive’ emissions are small, unburnt natural gas has a potent greenhouse effect. In the absence of reliable Australian data, we have assumed a level of fugitive emissions accounting for 40% of the overall climate impact of natural gas, based on international studies. Future escalation of coal seam gas extraction in Australia has the potential to increase greenhouse gas emissions, which would further improve the case for efficient electric appliances.


The research shows that households should no longer assume that natural gas is the cheapest or lowest emission fuel for space heating, water heating and cooking. This is a significant change to the last three decades of consumer, industry and government thinking regarding mains gas.

For virtually all new homes, efficient electric will be the most cost-effective choice.

Existing dual-fuel homes will need to carefully weigh their options. It requires a case-by-case analysis depending on many factors— however, the ATA report provides an excellent guide for consumers to undertake this analysis for their specific situation. Dig into the full report to find the results that apply to you. S

The research was conducted by ReNew‘s publisher, the Alternative Technology Association, and funded by the Consumer Advocacy Panel. The full report is available at

Read the full article and tables in ReNew 130.