In ‘Energy efficiency’ Category

window_xavie_v02 copy 400px

Not just window dressing: High-performance curtains and blinds

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Internal window coverings can protect privacy and dramatically improve the thermal function of a house, and if you choose with care, they can help keep you comfortable for years, writes Anna Cumming.

Windows are a complex and interesting part of the building fabric of a house. They admit light, warmth and fresh air; they connect the occupants visually with the outside world; sometimes they frame spectacular views. But from an energy efficiency point of view they are usually the weak link in the building structure. Through windows up to 40% of a home’s heating energy can be lost and up to 87% of its heat gained, according to Your Home. High-performance, double or even triple glazing helps this equation, as does careful consideration of window size, location and orientation. But to ensure the best thermal performance of your home, you’ll need effective window furnishings. Blinds, curtains and shutters can improve a window’s performance, make your home more comfortable and reduce energy costs.


What’s the purpose?

“Internal window furnishings serve a variety of purposes, including light control, privacy, reducing glare, heat reduction and heat retention,” says interior designer Megan Norgate of Brave New Eco. Soft window furnishings can also buffer sound. If you’re building or renovating, consider window treatments as part of the design process, because taking into account the associated requirements and thermal contributions may mean you make different decisions about the extent and location of your glazing.

It’s important to consider the main purpose when choosing window coverings. If minimising heat gain in summer is the main aim, it’s best to keep the sun off the glass in the first place with an external shading device such as an eave or awning (see our article on external shading options in ReNew 138). Semi-transparent blinds or curtains are a good option if privacy or glare reduction is the primary aim; they can be combined with heavier curtains for night-time heat retention.

Thermal performance is where great window coverings really come into their own: “They can act like de-facto double glazing if they are multi-layered and tight fitting to the window,” says designer Dick Clarke of Envirotecture. Snugly fitted and insulative blinds and curtains trap a layer of still air next to the window, reducing transfer of heat from the room to the window and thus outside. They also provide a feeling of cosiness: “If you are sitting in a warm room at night between an uncovered window and your heating source it is likely you will feel a chill, partly because of the draught created by the interior heat making a beeline for the cool exterior. Properly fitted and lined curtains and window treatments are the best way to avoid this effect,” explains Megan.

Read the full article in ReNew 140.

Induction cooktop and control area

Convert to induction

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Keen cook Sophie Liu loved cooking on gas until induction came along. She describes why it won her over.

IT’S BEEN two years since I researched and purchased an induction cooktop, and wrote a product profile for ReNew’s sister magazine, Sanctuary (see issue 30). Since then I’ve been using this new technology on a daily basis and it’s official—I’m an induction convert!


I am a keen cook and for the longest time I loved cooking on gas. But the advantages of induction for the environment and usability won me over. Like any new appliance, it took a while to get used to, and there are a few tips and issues worth pointing out and a few downsides to avoid. I’ve also outlined my good experiences and the many advantages of induction cooking below.

Renewably sourced electricity—one, Gas—nil

While cooking makes up a small part of a household’s energy use, it is still important to a home’s environmental footprint and running costs, particularly when other higher energy use areas have been addressed (see ‘Energy-efficient cooking’ and ‘Are we still cooking with gas?’ in ReNew 130). In terms of energy efficiency, ATA’s analysts have found induction comes out on top, just ahead of ceramic electric resistive cooktops, and with both these electric options ahead of gas hobs (input: induction 600 MJ/year, ceramic electric 667 MJ/year, gas 1200 MJ/year, all for the same energy output of 480 MJ/year).

ATA energy analysts estimate that energy use for an average household with a gas cooktop and oven is 2000 MJ/year—less than 4% of the average household’s energy use. By contrast, an induction cooktop and electric oven come out at 1000 MJ/year, 50% less. I also prefer electric induction to gas as I can run it on renewable electricity rather than using a fossil fuel.

With great power comes great responsibility

My experience of cooking with induction is that it’s the fastest, most responsive and most powerful method of cooking out there.

It took some time to get used to the faster, more powerful cooking. At the start, I certainly burnt or overcooked a lot of things—I even spectacularly ruined rice one night, which, with my Chinese heritage, is embarrassing to admit!

However, as with any new appliance, you gradually learn how to use it successfully. Now I know the power levels to start rice or pasta on, then what to turn them down to. We can slow cook things, too, and not have to worry about the gas going out, which often happened on low with our old hob.

Read the full article in ReNew 140.

SIPs house

Sealed with a SIP

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Last year the energy costs for this four-person household came to just $560, due to an airtight house design, a PV system well-matched to usage and a switch to all-electric. Kyle O’Farrell describes how they got there.

IN DECEMBER 2012 we were living in a small double-brick ex-Housing Commission home in the northern suburbs of Melbourne. With two growing kids sharing a bedroom and a very non-user-friendly layout, we knew it wasn’t going to work in the longer term. However, we liked where we were living and didn’t want to move. The house was built in 1953 and, aside from some minor wall cracking, it was basically sound and could probably be used as a base for a renovation. So what to do?


We asked architect Mark Sanders at Third Ecology to create three concept house designs for us: two incorporating the existing house and one a completely new build. To our surprise, the estimated cost for the new build was only around 10% more than the renovations. And, with the existing house set well back on the block, the most logical renovation design would mean building in our north-facing backyard with a significant loss of garden space, not something we were keen to do.

Thus we decided on a new build, given the benefits in orientation, block placement, reduction in project time and cost risk (renovations often throw up costly issues along the way), design layout and improved thermal performance.

The previous house was connected to the gas network, but we disconnected it during demolition and we wanted it to stay that way: for environmental, health and financial reasons, not least of which is that gas is a fossil fuel which contributes to climate change. We were also planning to install solar PV and wanted to maximise on-site usage of electricity, rather than pay the expense of a gas connection, gas plumbing and increasing gas prices. Finally, we were planning to build a very well-sealed house, so we felt that piping an asphyxiating and explosive gas into it was worth avoiding if possible. We also didn’t want the combustion products (mainly CO2 and water vapour, but also nitrogen oxides and carbon monoxide) in the house.

Around the same time, Beyond Zero Emissions released its Buildings Plan, which strongly supported going gas-free and outlined how to do it. Nice report.

Design for thermal performance

When it came to the house design, we liked the features of the Passive House approach to house construction, but knew there was a higher cost associated with the additional design, construction and certification requirements. Looking around for construction methods that could achieve similar insulation and air sealing, without additional building costs, we found structural insulated panels (SIPs). These are wall panels with a foam core and rigid panels glued to each side. The panels are weight bearing, so timber framework for the external walls is not required.

Read the full article in ReNew 140.

gas bill

Disconnecting from gas: what’s involved

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Just how do you disconnect from the gas network, and what will it cost? Consultant Kate Leslie investigates.

CONGRATULATIONS, your last gas appliance has been replaced and you are ready to disconnect. How to go about it and what should it cost?


Like all good answers, the answer to this one is “it depends”. It depends mostly on the state you live in and the distributor, a little on your retailer—and there could be an ‘X factor’ of how you approach it.

Generally, retailers are set up to compete for your switching business. Distributors are set up to connect new customers. The experience of dealing with a customer who wishes to disconnect, while not unheard of, is uncommon.

Many people who have disconnected from the gas grid simply organised with their retailer to close their account. The retailer expects you are moving house (and the next occupant will reconnect) or, in states with retail competition for energy, they might think you are taking your business elsewhere. The retailer will notify the distributor and the special meter reading for the final bill and disconnection of supply may or may not be a line item on the bill. Retailers vary.

Alternatively to disconnect, you might contact the distributor that owns the pipes and meters. They also have a set of in-built expectations. You might be demolishing your house (to rebuild it). Or, in infill developments, it is usual to remove the meter of a single dwelling, with the distributor coming back in a number of months or years to install multiple meters for the townhouses or apartments that now stand on the block. Or perhaps for some reason the property will be vacant for a while.

Distributors have options for disconnecting supply, other than physical removal of the meter. Some distributors use plugs and locks (usually where a customer is not paying their gas bill). One distributor in WA removes the pressure regulator. Some distributors say they will ask for enough information from the customer so they can determine the appropriate disconnection method.

Read the full article in ReNew 140.

Induction cooking

Money-saving results in Melbourne

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This family of four saved around $250 last winter by heating their home with a reverse-cycle unit instead of their older gas ducted system. They went on to swap out the remaining gas appliances, disconnect gas from their property and save even more. Stephen Zuluaga explains.

IN 2012, our family moved to a three-bedroom brick veneer townhouse in the south-eastern suburbs of Melbourne. The house was constructed in 2001 and it’s likely that’s when its original gas ducted heating, water heater and stove were installed.


We’d always been interested in keeping our energy costs down, but, like many people, we just assumed that high gas bills in winter were a part of life. We found that our two-month gas bill spiked significantly in winter due to heating, rising from around $80 in summer up to around $400 in winter.

Then in September 2015 I came across an article on The Conversation which proved to be a turning point. Tim Forcey’s article1 described research undertaken at the Melbourne Energy Institute which suggested that efficient electric appliances—heat pumps—could heat your home more cheaply than gas.

Intrigued, I got in contact with Tim to learn more. He introduced me to the My Efficient Electric Home Facebook group and, through contacts made there, I spoke to many efficiency experts and interested householders like myself about ways to reduce costs and increase efficiency.

In hindsight I can see that I was heading down the path of all-electric, but I wasn’t really looking at it like that at the time: it was just about replacing inefficient appliances with efficient ones.

There are many motives for wanting to improve efficiency and for us the primary driver was financial. Over the course of converting our house to all-electric, I spoke to others who had a combination of environmental, efficiency, financial and technological motives. I really like the fact that no matter what your motive is, you can get an outcome that both lowers costs and reduces environmental impact.

Read the full article in ReNew 140, or on the website of our partners Positive Charge.

pumping in wall insulation

Insulation upgrades

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Reader stories on how they improved the thermal performance of their homes, while reducing energy bills. By Eva Matthews.

Dennis Kavanagh has been incrementally improving his home in Blackburn, in Melbourne’s east, over the last few years. As well as deciding to go all-electric and installing a 9.8 kW solar PV system on his roof around 11 months ago, Dennis turned his attention to improving the home’s thermal performance through insulation and draughtproofing.

Little existing insulation


After attending a free EnviroGroup presentation run by ecoMaster on these topics, Dennis ordered a premium assessment for his home, which resulted in a number of recommendations and quotations to address them. They identified his ceiling insulation, which had been installed about 40 years ago, as being in reasonable condition but only rated R1.0. There was no insulation in the walls or underfloor. With Dennis unable to “crawl up or into awkward spots” himself, ecoMaster installed the insulation in the roof and underfloor in August 2015, both in the same day. Access to the roof was via the manhole; underfloor access was limited under the bathroom, laundry and some of the third bedroom, so they achieved around 70% coverage there.

For the walls, being brick veneer, Dennis’s best option was to have the insulation pumped in. As this type of application can cause a fire hazard, and the installers ecoMaster recommend require an electrical safety certificate, Dennis organised an inspection prior to the installation, using electricians from EnviroGroup. After checking behind power points and testing at the meterbox, and with Dennis having upgraded his wiring recently, they determined that all was good to go.

In January 2017, one man with a truck of granulated Rockwool (mineral wool) pumped in the insulation in less than a day. Most of the walls were accessible by shifting some tiles on the roof, through which the insulation was pumped in down a flexible hose. Solar panels were in the way in some spots, so not all the walls could be accessed from above; in this case Dennis thinks the insulation may have been pumped across from a neighbouring entry point. Holes were then drilled under the windows to pump into those lower spaces, and a mortar mix used to patch them. Although Dennis was somewhat concerned about whether it would match the existing mortar, he says it worked out well: “Unless you look closely, you don’t even notice it.” Also, batts were put in to fill gaps between the top of the timber wall framing and roof.

Read the full article, with two other case studies, in ReNew 140.

Nissan Leaf battery

Keeping your EV battery healthy

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In the first of a series, Bryce Gaton looks at the core part of the EV, its battery pack, and how to give it the longest possible life. In later articles, he will explain the options for testing and monitoring the battery pack in your EV.

WE ARE all familiar with the ways to prolong the life of an internal combustion engine (ICE) vehicle—regular service, monitor the oil, etc—but EVs are a whole new ball game. What do they need to maintain them in tip-top working order? And how can we test them to know if things are going wrong?


While in general EVs need less maintenance than conventional cars, there are some considerations which will help keep the car performing well for longer and reduce maintenance costs. The battery pack is the component that is both the costliest to replace and the most within our control to keep healthy.

For example, for an ICE vehicle converted to battery electric, replacing the battery pack can cost from $110 to $300 per lithium cell with the battery pack size ranging from 30 to 100 cells—at a cost of $3300 to $33,000. For a Nissan Leaf, replacing the 24 kWh battery is around $6500 fitted (AU$ equivalent to US$ replacement cost—Leaf replacement batteries are not necessarily available here).

What is an EV battery pack made of?

All the pure EVs and hybrids on the market now use variations of a lithium ion chemistry. A common one is lithium iron phosphate, commonly written as LiFePO4. Lithium offers many advantages over previous battery technologies. In particular, it allows for much lighter batteries than lead-acid, which is what EV batteries used to be made from.

Lithium batteries can also be more deeply discharged, down to 20% capacity, giving more available energy to take you further; they hold a stable voltage through most of their discharge range (see graph); they can take high charge and discharge rates, allowing for hard acceleration and fast charging; and they are largely maintenance-free.

They should also have a long life, if looked after, with 70% to 80% capacity remaining in the battery after eight to ten years. And even after that, lithium EV battery packs are still usable in less demanding applications, such as home storage

Lithium cells have some features that need to be taken into account in the design of the car and charging systems. If they are overcharged or discharged (below 2.5V or above 4V), they will likely be destroyed (although LiFePO4 are more abuse resistant and may be recoverable). And, in some formulations, they can catch fire. This is particularly a problem for the super light, very energy dense ones in phones and the like: think Samsung Note 7. EV batteries are now made with formulations that are more resistant to starting or maintaining a fire.

To allow for these issues, modern EVs and hybrids include a battery management system (BMS). The BMS is a complex set of electronics that manages the charging of each cell, as well as controlling the current available to drive as the battery discharges.

Read the full article in ReNew 139.

Shanghai maglev train

The future of long-distance travel

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We regularly look at the future of shorter range personal transport options, but what about long-range and public transport options? Lance Turner takes a look at where long-distance and public travel is headed.

TRAVELLING locally is already becoming more environmentally friendly, with the introduction of electric cars and public transport running from renewables. But what about long-range transport: what’s happening there? There is a global push towards reducing emissions in long-range transport options, be they rail, air transport or shipping, but there are significant challenges. Let’s look at what’s happening around the world, and how we may be getting around in the not too distant future.



According to the European Environment Agency (, emissions from all passenger rail (with an average of 156 passengers per train) in Europe are around 14 g of CO2 per passenger kilometre. Compare that to a large car (four passengers) of 55 g, a regular bus (12.7 passengers) of 68 g and aircraft (88 passengers) of 285 g. These figures will vary depending on the type of trains, cars and buses, as well as the source of generation for the electricity used (Europe has lots of renewables and nuclear compared to other regions such as the USA and Australia), but the indicators are clear—we need fewer planes and more trains.


High speed rail (HSR), where trains run at speeds above 200 km/h (for existing lines, or 250 km/h for new lines) between major population centres without stopping, is common in countries such as China (which has some 22,000 km of HSR network) and Japan, and throughout much of Europe. However, Australia has never managed to get a high speed rail network off the ground, despite many concepts and plans being put forward. One problem here has been a lack of political will for such long-term projects. Another problem, specific to Australia, is the huge distances between cities and our smaller population. In short, the cost per taxpayer for a high speed rail network is much higher in Australia than in most other countries, making it a difficult sell (see

Central to the lower environmental cost in HSR systems is the use of electric trains. Being able to derive power from renewable energy sources rather than on-board diesel engines means that high speed rail becomes an even cleaner transport option as the percentage of renewables in the grid mix increases—just like any EV. Further, the cost of transport is no longer tied to that of fossil fuels so, as renewables become cheaper, the cost per kilometre travelled can fall.

The majority of high speed rail networks still use steel wheels on steel rails, but some of the fastest HSR projects use a more recent technology—maglev, or magnetic levitation, where strong magnets are used to lift the train just above the track, eliminating most sources of friction and allowing for higher speeds. Indeed, the fastest HSR train in regular service is the Shanghai Maglev Train, which runs on a 30.5 km track from Shanghai Pudong International Airport to the outskirts of central Pudong.

Read the full article in ReNew 139.

Hydrogen fuel cell powered train

Hydrogen as a fuel – is it viable?

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Is the hydrogen economy ever going to happen and are fuel cell vehicles really a viable alternative? Lance Turner cuts through the hype and takes a realistic look at using hydrogen for transport and energy storage.

ANYONE interested in renewable energy will have come across numerous articles on hydrogen fuel cells, and in particular, their use in cars and other transport as a potentially greener replacement for conventional internal combustion engine (ICE) drivetrains. However, to date there are very few fuel cell vehicles on the roads, apart from a few in demonstrator fleets, all subsidised by either the government or vehicle manufacturers.


So why haven’t we seen the fuel cell revolution as promised? There are a number of reasons, but let’s first look at the basics of fuel cells.


What is a hydrogen fuel cell vehicle?

In its simplest form a hydrogen fuel cell consists of two electrodes (an anode and a cathode) separated by an electrolyte. Hydrogen gas is introduced at the anode and oxygen from the air at the cathode. The two combine to produce electricity, heat and water.

In a fuel cell vehicle, hydrogen is stored in high-pressure tanks and delivered to the fuel cell at a reduced pressure, while air is passed through the fuel cell stack (the common term for a number of fuel cells in a single unit) courtesy of an electrically driven compressor system. By varying the rate of gas flow through the stack, the electrical output of the fuel cell system can be controlled.

The electricity then normally passes through a DC to DC converter to produce a voltage suitable for the vehicle’s drive motor and battery bank (or ultracapacitor bank).

The resulting electricity powers one or more electric motors, which propel the car— exactly like a battery-based electric vehicle.

As mentioned, fuel cell vehicles include a battery or large ultracapacitor for temporary energy storage. This is required as a fuel cell takes a small amount of time to respond to gas flow rate changes. In a vehicle this would be an unacceptable delay—imagine putting your foot down only to have the car do very little for a couple of seconds. The battery and/or ultracapacitor store a relatively small amount of energy but they can deliver it immediately as a large amount of power. They also provide extra power when the total demand exceeds that available from the fuel cell stack (which usually has a lower maximum power output than the motors are rated for) such as when overtaking and hill climbing.

Indeed, the main difference between a purely battery electric vehicle (EV) and a fuel cell vehicle (FCV) is that the FCV has a combination of fuel cell system and small battery rather than a single large traction battery—in most other respects they are quite similar.

To store a usable amount of hydrogen in a small space, such as required for a vehicle drive system, you need to compress it enormously. How much does it have to be compressed? To gain acceptable ranges comparable to a typical petrol car or current long range EV (400 km or more), the level of compression is many hundreds of times atmospheric pressure.

Both Honda with their Clarity FCV and Hyundai with their ix35 vehicle use a maximum tank pressure of 700 Bar, or around 700 times normal atmospheric pressure, 70 megapascals, or over 10,000 psi in the old of pressure per square centimetre of tank surface area. terms. In more common terms, that’s 700 kg

Read the full article in ReNew 139.

Hot water savings

Efficient hot water buyers guide

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If your old hot water system has seen better days, maybe it’s time for an efficient replacement. We show you how solar and heat pump hot water systems work, what’s available and how to choose one to best suit your needs.

ONE of the biggest energy users in any home is water heating—it can account for around 21% of total energy use (on average, according to YourHome), at a considerable financial cost each year. Water-efficient appliances are one way you can reduce energy use—for example, you could replace an inefficient showerhead (e.g. some use 20 litres per minute) with the most efficient, which uses less than 5 litres per minute, saving water and water heating energy each time you shower. But far greater energy reductions are possible if you replace a conventional water heater with a heat pump, solar thermal or solar electric system.


Such systems have the added advantage of reducing your greenhouse gas emissions. For example, for an average family the reduction can be as much as four tonnes of CO2 per year—the equivalent of taking a car off the road!


What we do and don’t cover

From an efficiency and environmental point of view the future of household energy is electric. The rise of rooftop solar and the availability of GreenPower means that households can use 100% renewable energy to run their appliances, including hot water systems.

This means we don’t cover efficient gas hot water options such as gas instantaneous in this guide, although the solar thermal hot water systems listed do have gas boost options. Gas used to be seen as the cleaner energy choice, at least when compared with burning coal, but there are better non-gas appliances available to households now. And changes in the gas market mean gas prices are on the rise. Replacing a hot water system with a modern solar thermal or electric one is often the first step in disconnecting from the gas grid, and the associated costs and greenhouse gas emissions.

We cover systems designed for household hot water that can run from renewable energy, including electricity, and ambient and solar thermal heat. These include heat pump, solar thermal, electric instantaneous and the newer kids on the block, PV diversion and direct PV water heating systems. Heat pump systems can be designed for other purposes in the home such as pool heating or hydronic heating, but these are out of the scope of this guide.


Read the full article in ReNew 139.

Download the full tables from the guide here.

See an energy use comparison between heat pump water heaters and resistive element water heaters here.

Read a list of questions to ask your hot water system installer before giving them the job here.

Water heating ways

Getting into hot water

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Five reader stories and five different systems that illustrate there’s more than one way to get into hot water!

A tale of two solar hot water systems


Jen Gow has tried out both flat plate and evacuated tube solar hot water systems, and discusses the differences.


Don’t dismiss resistive element hot water

For Dave Southgate, converting to an all-electric house did not involve using a heat pump for hot water. Here’s what he did instead.


How to save money with a hot water heat pump

Jonathan Prendergast shares his quest to reduce his hot water bills by switching to a heat pump.


Troubleshooting issues with solar hot water

Ewan Regazzo’s electrical engineering background was put to good use troubleshooting a faulty solar hot water installation. It’s now working well, but there were several issues along the way.


Resistive versus gas

Linda and Mike Dahm were surprised when the energy costs for their dual occupancy homes, one with solar PV and an electric resistive hot water and one with gas hot water, worked out about the same. Here’s what happened.

Read the full article in ReNew 139.

Thermal imaging camera

Energy detectives

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Knowing that double glazing can be compromised by incorrectly sealed window frames, Jean and Barry Lambert used affordable thermal imaging technology to check and rectify the installation—and find other sources of house heat losses.

LIVING in Canberra’s cold climate you need to think carefully about heat loss. We’ve done work on our house to improve its insulation, glazing and heating system efficiency. But that doesn’t necessarily translate to the best possible thermal performance if there are gaps or weak spots in the insulation—and that’s where we found a thermal imaging camera came in handy.


Some background on our house

Located in an inner suburb of Canberra, our four-bedroom brick house was built in the 1970s. The major axis runs north–south, with the living area to the west (giving views to the Brindabella mountains) and the bedrooms facing east.

Canberra of course has quite a wide temperature range (it’s in climate zone 7). Outside temperatures on winter mornings can fall below zero, while summers are usually dry and warm.

Canberra’s cold winters dictate that insulation is a priority to reduce heat loss. We insulated the walls with R3 rockwool and we topped up the existing ceiling insulation to an R5 rating. We replaced the original oil heating with ducted gas, and added deflectors on the floor vents to direct hot air away from windows. By varying the airflow rate using the outlet dampers in the floor vents, around a 50 °C outlet temperature is maintained, giving a comfortable 18 °C to 20 °C temperature inside the house.

Read the full article in ReNew 139.


Keep your cool: External shading buyers guide

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With summers getting hotter in many parts of Australia, keeping the sun off your windows and out of your home is becoming even more important. Anna Cumming looks at the options for external shading, for both new builds and retrofits.

THERE’S been quite a shift from pre-industrial times when glass was an artisan-crafted luxury item, and homeowners were taxed according to the number of panes they had. These days, our houses are getting bigger and so are our windows—often to the point of comprising entire walls. Windows and glazed doors frame views, admit natural light and breezes, and allow a connection with the outdoors. In a well-designed house, they also admit the sun’s warmth in winter to assist passive thermal performance.


However, from a thermal efficiency point of view, windows are the weak link in a home’s building envelope: Your Home notes that up to 40% of a home’s heating energy can be lost and up to 87% of its heat gained through windows. Efficient double-glazed windows with thermally broken frames (preventing heat conduction through the frame) perform considerably better—advanced glazing solutions can exclude up to 60% of heat compared to plain single glazing—but will still allow more heat to enter in summer and escape in winter than the adjacent wall.

Internal thermal blinds or curtains can help a lot in preventing heat loss through windows in winter, but to tackle unwanted radiant heat gain in the hotter months, it’s far more efficient to stop the sun hitting the glass in the first place with appropriate external shading.

Location and orientation

There is a huge variety of options for keeping the sun at bay, from carefully chosen deciduous plantings and simple solutions like a piece of shadecloth on a frame, to awnings, shutters, blinds, and even pergolas with sensor-operated louvre roofs. To choose the best solution, firstly it’s important to consider your location and the orientation of your windows.

In most of Australia, shading is needed on windows on the north, and also the east (to prevent summer sun heating the house from early in the morning) and west (to block hot late afternoon sun). North of the Tropic of Capricorn, thought should also be given to shading windows on the south side of your house, as the sun’s steeply angled path in summer means these windows will also receive direct sun. Helpfully, the Geoscience Australia website ( allows you to find your latitude and calculate the sun angle at any time of the day, on any day of the year.

Find the table of suppliers here.

Read the full article in ReNew 138.


Island of energy: community-owned and renewable

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Denmark’s Samso Island went from complete reliance on imported oil and coal to 100% renewable electricity in just a decade. Jayitri Smiles and Nicky Ison explore the community and government partnerships that made it happen.

DURING the global oil crisis in 1973, Denmark began to think creatively about how to supply cheap energy to their population. As they built their first wind turbine, they were unknowingly establishing themselves as future world leaders in renewable energy.


Today, Denmark aims to have renewable energy powering 100% of their country by 2050 and to eliminate coal usage by 2030. These targets build on a track record of success: since the 1990s Denmark has witnessed the quadrupling of renewable energy consumption.

The creation of the world’s first fully renewable energy powered island, Samso, is an exemplar of Denmark’s leadership. Not only has Samso become a carbon-negative region, but it has accomplished this world-first using community investment.

In 1997, Denmark’s Minister for Environment Svend Auken was inspired at the Kyoto climate talks. He returned home with a passion to harness the collective efforts of local Danish communities in a way that promoted self-sufficiency in renewable energy. Auken held a competition, which encouraged Danish islands to consider how their clean energy potential could be achieved with government funding and matching local investment.

The most compelling application came from Samso, a small island west of Copenhagen with a population of 4100. This island of 22 villages, at the time run purely on imported oil and coal, was suddenly thrust into the global spotlight and, through a combination of local tenacity, investment and government funding, transitioned to 100% renewable power in just a decade.

At the heart of this energy revolution sit Samso’s community-owned wind turbines. Onshore turbines with a generation capacity of 11 MW offset 100% of the island’s electricity consumption. Another 23 MW of generation capacity from ten offshore turbines offsets Samso’s transport emissions. Most (75%) of the houses on the island use straw-burning boilers via district heating systems to heat water and homes, and the remainder use heat pumps and solar hot water systems.

The extraordinary result is a carbon-negative island and community. The island now has a carbon footprint of negative 12 tonnes per person per year, a reduction of 140% since the 1990s (compare this to Australia’s footprint of 16.3 tonnes per person in 2013 and Denmark’s overall footprint of 6.8). Not only is the island energy self-sufficient, they now export renewable energy to other regions of Denmark, which provides US $8 million in annual revenue to local investors.

And Samso is not slowing down. Highly motivated, knowledgeable and passionate locals are aiming for the island to be completely fossil-fuel free by 2030. They plan to convert their ferry to biogas and, despite already offsetting their vehicle emissions via renewable energy generation, residents of Samso now own the highest number of electric cars per capita in Denmark.


Read about their transition in ReNew 138.


Straight up: vertical garden design

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The last thing you want is to spend a lot of money on a vertical garden system and then have it fail. Jenny and Bevan Bates provide advice and inspiration from their own living walls—five years old and growing strong!

THE inspiration to garden vertically is not new. The Hanging Gardens of Babylon, if they are more than legend, may have been an early precursor, built to bring luscious greenery to the ancient city’s terraced buildings. Your grandma’s hanging pots are a more down-to-earth example, as are vines on a trellis.


More recently, the idea of living walls has become a popular trend, in part in response to higher density living and homes with small gardens. For Jenny and Bevan Bates, their move to a new house with a small courtyard— and a stark black brick wall facing their living area windows—was the reason they started experimenting with gardening on a wall.

“You have to be prepared to experiment,” says Jenny. In fact, their first vertical garden was a failure. “We tried a $100 system, but the pots were too small and it dried out too quickly; it was hard to keep anything alive in it,” she says.

However, they persevered and they now have five vertical gardens providing cooling, colour and herbs, which adds interest to their home. The black brick wall in fact sets off one of the vertical gardens nicely—the colour they didn’t like turned out to be complementary to the planting!

That particular garden was their first success, says Jenny. It’s now five years old and thriving. It’s on a south-facing wall overlooked by the north-facing living area windows—a lovely sight.

They created the garden using Woolly Pockets, a product which at the time they needed to get delivered from the USA (though there are now retailers in Australia).

The pockets are composed of long troughs of recycled polyethylene (PET, from milk bottles for example). That recycled aspect was important to them; “You need to think about the full life cycle; for systems made from virgin plastic, there can be a lot to dispose of at end of life,” says Jenny.

Which plants they use has evolved over time; some plants grew bigger than expected, shaded other plants or didn’t like the position.

Read about their vertical garden in ReNew 138.


Reusing building materials in the garden

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There are many uses for old building materials in the garden to create quirky but useful structures, with the added advantage that the materials don’t end up in landfill. Permaculture gardener and teacher Drew Barr shares his tips.



Bricks are useful objects. Durable and cheap, their regular shape means they can be stacked or laid in patterns. Almost all bricks have the same dimensions, although older handmade bricks may be slightly smaller. The size and shape are designed for easy one-handed handling by an adult.

Bricks are energy-intensive to manufacture and transport, but will last hundreds of years, and can be used over and over again.

When reusing bricks, you’ll need to clean them to remove the mortar. This is dirty and laborious work and seems very slow to begin with, but once you have mastered the knack you will be surprised how fast you can clean bricks. The best tool for this is a scutch hammer, which has replaceable toothed blades called combs. Chip at the mortar where it meets the brick and it will come off in big chunks. Wear gloves and a face shield though as flying mortar chips really hurt.

Broken concrete slabs
Concrete is also a very energy-intensive material to manufacture, and similarly highly durable and strong, and ideal to reuse.

Concrete slabs, sometimes referred to as ‘urbanite’, can be reused to make crazy paving, or stacked without mortar to form low retaining walls. When sourcing slabs make sure you get only non-reinforced slabs such as from council footpaths or old driveways. Reinforcing steel in the concrete is very difficult to cut, and as it rusts it will swell up and split the slab.
Councils often replace footpaths and must dump the slabs of concrete they remove, and they will usually be happy to dump it at your place for free.

Read more on reusing old concrete slabs, clay pavers, roofing tiles, roofing iron, car panels, bathtubs and more in the full article in ReNew 138.


ATA member profile: Ripples in the community

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Long-time ATA member Ali Campbell has no qualms about buying secondhand instead of new and looks at all purchases through a “green lens.” She talks to Jodie Lea Martire about how community is critical to sustainability.

ALI Campbell couldn’t bear to see her old piano go to waste, so it stands in the chook shed as a piece of art. It’s a good demonstration of her creative commitment to sustainability, which has led from high eco-living standards at home to diverse community involvement. As Ali says, being part of an active community “helps sustain you and recharges you for staying in the sustainability field.”


Bushwalking and camping gave Ali a connection with nature, but her real evolution towards environmental action came with her first child. She and husband Bruce had been “unwise, unwary consumers until that point”, but they realised that every other parent had also needed clothes, cots and change tables so they could use “secondhand everything.” From there, the Campbells took a good look at their “consumption and stuff.” They reduced purchases, packaging and waste, considered where their food and goods came from, and boosted their home chook-and-vegie garden.

The garden led to conversations about sustainability with others, and builder Duncan Hall put Ali and Bruce on to the ATA. Soon, the family was experimenting with solar stoves, and now “everything we do has that green lens.”

They have worked to reduce their home’s environmental impact, including greywater systems, water tanks, double-glazed windows, reorienting for better lighting and using Australian-made materials. Ali used ATA-sourced information to explain her decisions to both their builder and plumber during renovations, and emphasises that it’s crucial to hire workers who ‘get it’ and aren’t just greenwashing their work.

Ali says, “The community thing is critical. It goes without saying, but it needs to be said.” She spent six or so years volunteering as an organiser with Melbourne’s Sustainable Living Festival (SLF), and gardened with the Stephanie Alexander Kitchen Gardens in Altona Meadows for a time. She is also active on the Inner West Buy Swap Sell and Freecycle Facebook groups.

Ali participates in Transition Hobsons Bay (THB), and she and Virginia Millard run the Give Take Stand: an unstaffed booth where people share quality, unwanted items (like a free op shop). Ali says the autonomous setup has strengthened community involvement without forcing obligation or onus on anyone. It has been hosted in venues around Hobsons Bay and the council is providing funds to boost the work and establish the stand as a waterproof outdoor shed.

Another project Ali organises through SLF and the transitions group is Bunches of Lunches. Now in its third year, Ali and Transitions Hobsons Bay member Tarius McArthur run three-hour sessions which teach participants to cook five healthy, freezable dishes suitable for school lunches—and promote local food, low packaging and low energy use.

Ali and Bruce have also combined their home and community efforts by signing up their new seven-seater VW Caddy to Car Next Door, allowing locals to rent their vehicle. This let the Campbells balance their need for a second car every now and then, while knowing they’re “not just sitting on this asset.”

Reading ReNew gives Ali great ideas, a sense that she’s not alone in her activism, and—most importantly—hope. The magazine’s coverage of policy developments, news analysis and innovations provides “positivity and support, and that’s what keeps her doing this.”

To end with Ali’s own assessment of her environmental contribution: “I can feel frustrated because I’m not creating seismic change, but I hear frequently, most weeks, ‘You’d love this, Ali!’, so I know I’m having a ripple effect around me and I just hope that keeps rippling on and on.”

This member profile is published in ReNew 138. Buy your copy here.


Tassie off-grid home

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Given their distance from the nearest power pole, it made sense financially as well as philosophically for this Sydney couple to go off-grid in their new home in Tasmania. Peter Tuft describes how they went about it.

As we approached retirement my wife Robyn and I knew we did not want to spend the rest of our lives in Sydney. Sydney’s natural environment is glorious but it is also much too busy, too hot and humid in summer, and our house was too cold and hard to heat in winter. We had loved Tasmania since bushwalking there extensively in the 1970s and it has a lovely cool climate, so it was an obvious choice.


We narrowed the selection to somewhere within one hour‘s drive of Hobart, then on a reconnaissance trip narrowed it further to the Channel region to the south. It has lush forests and scattered pasture with the sheltered d’Entrecasteaux Channel on one side and tall hills behind—just beautiful. And we were extraordinarily lucky to quickly find an 80 hectare lot which had all those elements plus extensive views over the Channel and Bruny Island to the Tasman Peninsula. It was a fraction of the cost of a Sydney suburban lot.

The decision to buy was in 2008 but building did not start until 2014 so we had plenty of time to think about what and how to build. We have always been interested in sustainability, and renewable energy in particular, even before they became so obviously necessary: my engineering undergraduate thesis in 1975 was on a solar heater and Robyn worked for many years on wastewater treatment and stream water quality. There was never any doubt that we would make maximum use of renewable energy and alternative waste disposal methods.

From the beginning we knew the house would be of passive solar thermal design. The house sits high on a hill (for the views!) and faces north-east. The main living room is entirely glass-fronted, about 11m long and up to 4m high with wide eaves. That allows huge solar input to the floor of polished concrete. A slight downside is that there is potential for it to be too warm in summer, but we’ve managed that with shade blinds and ventilation and so far it has not been a problem. All walls, floor and roof are well insulated, even the garage door, and all windows are double-glazed. Supplementary heating is via a wood heater set in a massive stone fireplace chosen partly for thermal mass and partly because it just looks awesome. Warm air from above the wood heater convects via ducts to the bathroom immediately behind the chimney, making it very cosy indeed.

Read the full article in ReNew 137.


Still a clever country

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Energy efficiency consultant Geoff Andrews admires Australian innovation, but, as has often been noted, finds the next step—commercialisation—is lacking. Collaboration, governments and risk-taking could all improve that, he suggests.

I view innovation as change for good, so change which improves sustainability clearly qualifies. Most readers of ReNew would agree that we have to improve the sustainability of our society, so we must innovate. But, how do we do that, and what lessons can we draw from Australia’s sustainability innovation performance to date?


There is no question that Australia has provided the world with more than its share of innovations, including in sustainability. In renewable energy alone, Australia has led the world in PV efficiency for decades, pioneered many improvements in solar water heaters, and is now developing wave energy. We’ve been first or early implementers of two flow battery technologies (vanadium redox by Maria Skyllas-Kazaco at UNSW in 1980 and zinc bromine by RedFlow). Scottish-born James Harrison built one of the first working refrigerators for making ice in Geelong in 1851 (before that, ice was imported from Canada),and we invented wave-piercing catamarans and the Pritchard steam car. We even had manned (unpowered) flight by heavier-thanair craft a decade before the Wright brothers with Lawrence Hargrave’s box-kite biplane.

Of course, Australian innovations are prevalent in many other sustainability areas including medicine, construction, agriculture and fisheries, but space is limited here. What we could have done a lot better is commercialising those innovations in Australia. Imagine if Australia led the world in the manufacture of solar panels, refrigerators, air conditioners, wi-fi devices and evacuated tube heat exchangers, the way we do with wave-piercing catamarans and bionic ears.

Improving commercialisation would provide funds to improve our budget bottomline and allow us to do even more innovation and more commercialisation. To achieve this, I think we need to do several things.

Read the full article in ReNew 136.


The world’s first baker

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Why don’t we know about the oldest grinding stones in the world, found in Australia, or the crops cultivated by Aboriginal Australians? Bruce Pascoe is helping change that.

If you were asked who the world’s first bakers were, what would your answer be? Most would think first of ancient Egypt where it is believed bread was first baked around 17,000 BCE. And yet there is evidence to show that grindstones in Australia were used to turn seeds to flour 30,000 years ago. Archaeologists found the evidence for this at Cuddie Springs in New South Wales in the shape of an ancient grinding stone which had been used to reduce grass seeds to flour. These were the bakers of antiquity. It took Egypt 12,000 years to repeat this baking experiment. Why don’t our hearts fill with wonder and pride?


Australian sovereign nations cultivated domesticated plants, sewed clothes, engineered streams for aquacultural and agricultural purposes, and forged spiritual codes for the use of seed in trade, agricultural enterprises, marriage and ceremony.

This was and is an incredible human response to the difficulties of fostering economic, cultural and social policies. It may be unique in its longevity but also in its ability to flourish without resort to war. Australia’s reluctance to acknowledge what was lost can be witnessed in our ignorance of the birth of baking, the gold standard of economic achievement.

Why is this? Is it a malicious refusal to recognise the economic triumphs of the people from whom the land was taken or a simple culture of forgetting fostered by the bedazzlement of Australian resources and opportunities?

If we could rid ourselves of the myth of low Aboriginal achievement and nomadic habits, we might move toward a greater appreciation of our land. We might begin to wonder about the grains that explorer Thomas Mitchell saw being harvested in the 1830s, and the yam daisy monoculture he saw stretching to the horizon of his ‘Australia Felix’, the early name given to western Victoria. These crops must have been grown without pesticides and chemical fertilisers and in harmony with the climate; surely they are worthy of our investigation.

Read the full article in ReNew 136.