In ‘Energy efficiency’ Category

ReNew 141: Store your solar

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

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

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

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

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

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

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

Robyn Deed
ReNew Editor

ATA CEO’s Report

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

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

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

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

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

You can purchase ReNew 141 from the ATA webshop.

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All-electric and hydronic

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There’s a lot to learn from this highly insulated and well-sealed renovation in Melbourne, not least how a heat pump is providing both hydronic heating and hot water. Cameron Munro explains the house’s modelling-led upgrades and the tweaks made along the way.

WHEN we bought our 1910 weatherboard home in inner suburban Melbourne, we were committed to making it as comfortable and energy efficient as we could. We’d partially renovated a previous home by installing double glazing and injecting foam into the wall cavity, but our new home presented the opportunity to do a far more extensive renovation.

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Our approach was guided by the German Passivhaus movement (also known as Passive House in Australia), which requires extensive insulation and extreme attention to thermal bridging and airtightness. We really liked this approach as it’s guided by building physics and requires extensive modelling and verification.

Moreover, we weren’t comfortable with the usual practice of simply throwing energy into a building to keep it comfortable; whatever additional heat we needed, we wanted to ensure we could keep it within the building envelope for as long as possible.

First things first: going off gas
The previous owner used a conventional gas storage hot water system and gas heaters. Our strategy for heating and hot water was always going to be all-electric using an air-source heat pump and solar PV.

We liked the simplicity of minimising our grid connections and had concerns about the carbon footprint from gas production and use.

One of the first things we did was to have the local gas network utility remove the gas meter and cap the gas main in the street. This was surprisingly easy to do, and cost us nothing.

Read the full article here.

monitoring_guide_phone

Knowledge is power – Energy monitoring guide

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Need help getting the upper hand on your electricity bills or checking that your solar system is working? You should consider an energy monitoring system, says James Martin from Solar Choice.

DO YOU have a clear picture of what’s drawing electricity in your home right now? If you’re like most Australians, you probably don’t.

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Historically, this hasn’t been an issue because electricity bills weren’t a major concern for most households and, in any case, the number of devices was probably small. But these days electricity prices are high and there are likely to be more electricity-consuming devices plugged into the walls of any given home than the occupants can think of off the top of their heads.

Many Australians have turned to solar panels to help them fight rising prices. Rooftop solar is now affordable and commonplace — the Hills Hoist of the 21st century.

However, comparatively low solar feed-in tariffs in most places mean that solar homes have less incentive to send solar electricity into the grid and more incentive to use it directly. Despite this fact, many (if not most) solar system owners would be at a loss if you asked them how much energy their system produced yesterday, never mind the proportion that they managed to self-consume.

Solar systems have even failed without the homeowner realising until they received their next bill. So monitoring is important!

Types of energy monitoring and management systems
Thankfully, there’s a growing number of products on the market that shed light on household energy consumption and solar generation. These devices take a range of approaches and offer a range of functions, but can generally be classed as either monitoring systems or management systems.

As the name implies, a monitoring system enables the user to ‘see’ what’s happening with their electricity, usually via an app or web-based portal, whereas a management system lets them not only observe but also ‘reach in’ and control which devices switch on at what times.

In reality, the line between the two is becoming increasingly blurred as platforms that once offered only monitoring get upgraded to let them do more.

Monitoring and management systems can be lumped into roughly five categories based on how they are physically installed in the home.

Read the full article in ReNew 141.

1940s cottage with battery

Battery system case studies

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1940s cottage with battery

IN 2016 Liz and Charlie extended and renovated their 1940s cottage in Ainslie, a suburb of Canberra, applying passive solar design to the extension and retrofitting insulation and sealing to the existing home.

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In early 2017, they also added 4.48 kW of solar, an LG Chem 10 kWh battery and Reposit software, costing around $20,000 as a package, after an ACT government subsidy.

“We chose to get a battery as we wanted to maximise self-sufficiency,” says Liz. They like that the battery allows them to use their generated electricity at night. They chose the LG Chem battery as it didn’t need to be undercover.

Their average usage is around 8 kWh to 9 kWh per day and currently, according to Reposit, they’re achieving 96% to 98% self-consumption, depending on the weather (and therefore their solar generation) and their electrical load for the day.

“Yesterday it was partly cloudy, and we generated 26.8 kWh, used 9.9 kWh ourselves, exported 17.2 kWh and imported just 0.3 kWh,” says Liz. “That’s pretty typical.”

The battery is generally fully charged by 11 am; on a sunny day it can be charged by 9.30 am, and occasionally not until the afternoon if it’s very grey.

The real-time monitoring available via Reposit is fascinating, says Liz. “It gives us useful feedback on our electricity usage patterns and, as a result, we make better choices about electricity consumption.”

For example, they noticed their hot water heat pump was coming on during the night when they’d prefer it to operate during the day from solar, so a timer to prevent that happening is on their to-do list.

Retiring sustainably

WHEN Julie May retired and bought a new home in Canberra, she decided to invest her savings in a sustainable lifestyle to reduce both her environmental footprint and her cost of living in retirement.

The house already had some good energy-efficient features including R3.5 ceiling insulation, R2 wall insulation, north-facing living areas with eaves to exclude sun in summer, high/low windows for cross-ventilation and a Daikin split system for heating and cooling.

Her changes began in July 2015 with the purchase of an Audi A3 e-tron plug-in hybrid electric vehicle, followed by installation of a 4.5 kW solar system (Nov 2015) and a 6.4  kWh Tesla Powerwall with Reposit for energy management (Aug 2016).

Julie also disconnected from gas in 2016, switching from instantaneous gas to electric-boosted solar hot water. Her gas bills previously comprised 80% fixed charge and only 20% for the gas itself, so going all-electric has meant a big saving.

She can now run her home and car mostly off solar and the stored energy in the battery, thus keeping imports low (1 to 2.5kWh/day, down from 10 to 23 kWh/day, counting electricity and gas).

Other notable achievements:

  • Julie has travelled 18,000 km in her Audi over the last two years and averaged just $155/year for petrol.
  • Reposit monitoring has meant she’s been able to better stagger appliance use so that grid energy is seldom required.
  • Julie has been paid Reposit premium GridCredits on several occasions for providing energy from the battery when there was high peak demand, e.g. she was paid $5.24 for four ‘grid credit events’ on 10 Feb 2017.
  • She also runs a cordless battery-powered mower as part of her all-electric home!

Eco additions

GREG and Maria built their passive solar house in Sydney in 1988, with a view to living as sustainably as possible. As technology has improved and become more affordable they have added more sustainable features.

A solar hot water system was the first addition in 1990, followed by 6000 L of rainwater storage in 2009, 2.8 kW of solar PV in 2010 and double glazing in May 2017.

Then, just six weeks ago, in late July 2017, they added a Tesla Powerwall 2 with 14 kWh of battery storage ($9300 installed).

Their motivations included to increase use of their solar and to ensure supply during blackouts, particularly to run tank pumps as they are in a bushfire zone.

The house’s energy consumption averages around 10 kWh per day, and the solar and battery were sized for this.

They expect they’ll use a little from the grid during the winter quarter, but they should be pretty well energy independent the rest of the year.

So far, the system has performed better than expected, with just a few days requiring grid draws of up to 2.5 kWh—usually when they’ve used their fan heater in the evening.

The battery charging and discharging is not timed—“it just works,” says Greg. “My experience is that there’s no need to manage it. So far, our limited experience is that if there’s a sunny day, the battery gets to 100% during the day with a small amount of grid export after that, and then the house runs off the battery all night.”

They can now run multiple appliances without drawing energy from the grid. Greg notes: “Being AC-coupled, the battery and solar add together, so we can supply a load of 7 kW quite easily, which was not possible before the battery.”

 

Read the energy storage guide and more case studies in ReNew 141.

Beyond the Stars

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There’s much more to be gained from an energy rating tool than the number of Stars. Sid Thoo and Alex Raynes-Goldie demonstrate how an energy rating tool can help tweak the building’s orientation, materials, shading and more.

THE Nationwide House Energy Rating Scheme (NatHERS) ranks a home’s potential thermal performance (heating and cooling needs) based on its proposed design and construction. NatHERS is often used to demonstrate that projects meet the mandatory energy efficiency requirements of the National Construction Code.

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In Australia, new residential projects are generally required to meet a minimum 6 Star NatHERS rating.

NatHERS is, however, more than just a certification tool. By estimating a home’s potential heating and cooling needs based on different design and construction options, NatHERS can be a useful tool in identifying the best design strategies for your unique project.

Good design can reduce the amount of energy needed to keep a home comfortable, often with little or no additional cost.

Many ReNew readers will know the fundamentals of designing a more energy-efficient home—NatHERS can help take this one step further, testing how to apply these principles to get the best value for money.

Using an example house design, we will look at some of the fundamentals of energy-efficient design and discuss how NatHERS can be used to inform the design process.

1. Climate
Understanding climate is the first crucial step in designing a more energy-efficient, eco-effective home. It’s for this reason that passive solar design is sometimes more accurately referred to as climate-responsive design.

In Australia, the National Construction Code identifies eight distinct climates around the country, ranging from hot-humid to alpine conditions (see www.yourhome.gov.au/passive-design/design-climate).

NatHERS breaks these down further into 69 climate zones, based on historical climate data which also takes into account solar radiation, wind speed/direction, temperature and humidity.

Because different climates warrant different design responses, a six Star house in Melbourne is very different from a six Star house in Darwin. Melbourne is a heating load dominated climate (i.e. more warmth is needed to achieve thermal comfort), whereas cooling is the main issue in Darwin.

Thus, it’s vitally important to prioritise the most appropriate design strategies for the particular climate.

This means the six Star scale is calibrated differently for each climate zone, depending on whether heating and/or cooling is required to achieve thermally comfortable conditions.

BASIX (a NSW-based rating tool) goes one step further and applies separate targets for heating and cooling, which can help to further fine-tune the thermal performance of a design.

Read the full article in ReNew 141.

Blower_door_testing

Why test for air leakage?

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Energy efficiency consultancy SuHo explains the hows and whys of testing for air leakage in your home.

AN INTERESTING subject presently under discussion and development in the home construction industry is air leakage from buildings. You may have heard of terms like air permeability, air infiltration, air change rate and air flow rates. All of these terms relate to building air leakage testing, or ‘blower door’ testing.

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What air leakage is and how it relates to home energy efficiency is commonly misunderstood. Air leakage is the unintentional introduction of outside air into a building and can account for up to 25% of winter heat loss. It occurs via uncontrolled openings such as gaps and cracks. Note that this differs from ventilation, which occurs via controllable openings such as doors and windows.

Testing for air leakage
‘Blower door’ testing is a method of testing how and where a building leaks.

It uses a high-powered fan mounted within an adjustable frame to control pressure levels within a building. The fan is mounted into an external door opening.

All controlled external openings (doors, windows etc) are closed for the test, while all mechanical ventilation outlets (such as exhaust fans) are left unsealed and internal doors are left open.

A blower door test is non-obtrusive and takes a couple of hours.

The rise in pressure elevates air flow through any uncontrolled leakage points such as gaps, cracks and poorly sealed door and window frames, as well as through non-baffled fans. These are photographed using a thermal camera, which differentiates surface temperature from cold (blue) to hot (red).

An added benefit is that the thermal imaging has the ability to identify such idiosyncrasies as missing or disturbed insulation batts, water ingress and electrical faults.

Losing just 5% of the total insulation area of a ceiling effectively halves its performance (based on ceiling insulation calculations from the National Construction Code Volume 2 Section 3.12.1.1 Building Fabric Insulation; see also ReNew 140, p. 84).

The result is generally a building fabric audit report, provided to the homeowner and detailing all results, observations and recommendations, and quantifying potential savings.

Read the full article in ReNew 141.

thermal stratification

Home truths: notes from an energy assessor

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After conducting home energy assessments for several years, Richard Keech shares some of the all-too-common problems he sees.

Since mid 2015 I’ve worked doing building energy assessments in Victoria, mainly for homes and mainly on behalf of ecoMaster. In that time I’ve visited about 290 clients to inspect their premises. In this article I’ll try to convey insights about homes and energy based on my experiences. Some of this is specific to Victoria’s housing stock and temperate climate and some applies to all homes.

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The assessment process itself
Winter thermal comfort is the biggest motivator in Victoria
I usually begin by asking clients what motivated their interested in an assessment. By far the most common response—probably three-quarters—is thermal comfort. Of that, most is winter thermal comfort. So whatever concerns people may have, it’s thermal discomfort that turns their interest into action. Given the current media discussion about energy costs, it’s interesting that cost is actually far behind thermal comfort in getting people engaged in the process.

People like to talk about their house
There’s an element of therapy about consulting on home efficiency that goes well beyond people simply receiving information about the state of their homes. It’s very much a two-way process. So patiently listening to people talk about how their home does or does not work seems to help people engage in the issue of home energy and comfort.

People don’t value professional advice highly enough
I’m very lucky to work for one of the few companies that consult on home energy efficiency. But even so, many people expect a lot for nothing, especially when it comes to draught proofing and general advice. Understanding a client’s home, sufficient to specify the many things typically needed to draught proof a home, is time-consuming.

The people who most need professional advice are the least likely to get it
A tiny fraction of households seek professional advice about their homes’ efficiency. And I expect that the homes we see are far from being the worst out there.

Tenants are missing out
Only a tiny fraction of our consultations apply to rented premises. Landlords and tenants both obviously lack the motivation to spend the money on a consultation because the cost and benefit incentives are misaligned. As a country we need ways to motivate landlords to improve their properties for the benefit of the tenants. This is worthy of a whole separate discussion; e.g. see www.bit.ly/TCRLOIC and ‘Energy-efficient renters’ in ReNew 134.

Read the full article in ReNew 141.

curtain-making workshop

On the way towards zero net energy

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In November 2014, Uralla in NSW was awarded the opportunity to become Australia’s first Zero Net Energy Town. From the start—and one of the key reasons their submission was successful—this has been a story of community engagement and contribution, with whole-community benefit at its heart.

A blueprint for action
While other communities are moving towards 100% renewables in different ways, Sandra says that the “Z-NET Blueprint really gave us a focus and an overarching goal.” One of the first things the group did was to set a vision and mission for Z-NET Uralla, to guide decision-making around which activities to undertake.

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As a relatively conservative population (“We’re not tree-huggers, we don’t talk about climate change or greenhouse gas emissions”), their focus is on renewable energy, energy efficiency and saving money on energy bills.

The group’s activities reflect this, and are centred around education and advising practical actions.

While the blueprint for Uralla (a shire of around 6000 people in 2200 households) is moving them towards 100% renewable energy for stationary use (i.e. not including transport) over a 10 to 15 year timeframe, Sandra notes that “at this stage, we are focused on energy efficiency and rooftop solar PV.”

She adds that the level of resources available (funding and volunteers’ time) has determined what the group has been able to achieve to date. But even with these constraints, they’ve achieved a lot over the past couple of years.

Energy efficiency first
The group received grants from both the Murray–Darling Basin Regional Economic Diversification Program and the NSW Office of Environment and Heritage, along with great support from the Uralla Shire Council. This enabled them to recruit a project officer to run free business and home energy-use reviews, with help from volunteers.

To date, 23 local businesses (including cafes, a brewery, orchard and dairy) have had an energy-use review, using thermal imaging and monitoring equipment donated by a Z-NET Uralla member. The equipment enabled businesses to get energy-use information specific to their business; for example, one café had eight meters installed on circuits for the coffee machine, fridges and ovens.

Read the full article in ReNew 141.

Orientation matters!

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With a low average energy use of under 5 kWh/day, Ewan Regazzo shares the lessons he and his family have learnt from building a new energy-efficient home on a budget.

OUT walking the dog one day in my local area—a relatively modern and well-established suburb in Maitland, near Newcastle in NSW—I stumbled across a small, secluded cul-de-sac that contained a huge (1117 m2) vacant block.

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It appeared to be one of the few blocks remaining in the suburb and the faded and forlorn ‘for sale’ sign at the front, barely visible among the overgrowth, indicated it was still available.

Perhaps it wasn’t popular because of the site: the land was south-facing and fairly steep and narrow at the front, with a softer rise to the wider rear section. Further research showed it had a development application in with council for two narrow subdivisions, each with a small three-bedroom house, and I decided to invest with the idea of building two houses on the site, one for myself.

At that time I was living in a rental property which, although fairly modern, was a poor example of house design.

The rental house was unbearably hot in summer; aligned east/west, the lounge room was uninhabitable come afternoon.

In winter it would get down to 3 °C in the master bedroom and the gas heating in the open-plan living area provided little comfort for the financial outlay. In Maitland’s warm temperate climate, with hot summers and mild winters, passive solar design should work well, but it seemed this 15-year-old house had been built prior to the discovery of insulation and decent solar orientation!

Passive solar design was something I had been interested in for some time. I first came across ReNew way back in 1995, and had pored over copies of Owner Builder magazine, and had even investigated what I needed to do to be an owner-builder myself.

Full-time work meant owner-building wasn’t feasible, so I began investigating local builders to see what was available. I visited home display centres, walking through house after house and scrutinising plans for something that would work on my block. I ended up despondent: few designs considered site orientation and few builders were prepared to depart from a rigid formula that allowed for a quick, low-cost build at the cost of long-term efficient energy use.

Read the full article in ReNew 141.

140 Front cover 200 x 262 pixels

ReNew 140 editorial: It’s electrifying – the benefits of changing fuels

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AS ONE of our case studies says, many living in the colder parts of Australia have long assumed that winter equals high energy bills (often gas) for heating. But what if that association could be changed, with benefits for both the hip pocket and the environment?

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Over the last few years, the ATA, ReNew’s not-for-profit publisher, has been promoting a shift to efficient electric appliances for the three major energy users in the home— heating/cooling, hot water and cooking—with the important message that in many cases this shift will be both cheaper for the householder and better for the environment. It’s a message that is resonating with many committed to making sustainable changes at home.

Another of our case studies makes the point that part of the reason for the shift is the tremendously improved effectiveness of new state-of-the-art efficient electric options; how much better is a heat pump for heating over an old electric bar heater, or the responsiveness of an induction cooktop over the old electric coil cooktops (I still remember the excitement at the covered coils on my parents’ new stove in the 1980s!).

Apart from case studies, the ATA revisits its modelling of the economics of going all-electric, including how having solar panels helps in the financial equation. We also answer some commonly asked questions: how do you disconnect from the gas network; when do you need to start thinking about three-phase or a higher amperage power connection; and can a keen cook be wooed away from cooking with gas, even if they are ‘wokstars’ (short answer: yes)?

There’s much more in the issue besides. Staying warm is not just a heater choice— house design, draughts and insulation all need to be addressed. Our buyers guide looks at insulation—what’s available and where it’s needed—along with installation case studies and the warming results. Plus we look at window coverings, including the beauty of high-performing honeycomb blinds adopted in many of our case studies.

Designing with structural insulated panels (SIPs) also gets highlighted this issue, with two houses using this prefab construction approach to produce well-sealed, high-performing homes. These projects suggest a shift towards thinking about air tightness, with several houses also using blower door tests to find out just how sealed they are.

We also cover one of the most inspiring outcomes of the Community Energy Congress, held in March this year. With many representatives from Australian and other First Nations communities, out of the congress came the formation of an alliance of First Nations peoples seeking a renewables pathway to energy justice for their often remote and poorly served communities.

Stop Press! The ATA has just won not one, but two awards from the United Nations Association of Australia, one for climate change leadership and one for Sustainable House Day’s role in education and engagement. Great stuff

Robyn Deed
ReNew Editor

ATA CEO’s Report

THOUGH very disappointing, it came as no surprise to many that Donald Trump followed through on his election promise and pulled the United States out of the Paris agreement on climate change. The USA joins Syria and Nicaragua as the only UN member countries not to sign the agreement.

Donald Trump’s move seems to have only strengthened the commitment of others to take the lead on action on climate change. The momentum for a low-emissions future grows apace with the price of renewable energy continuing to fall—it is now cheaper to develop solar and wind energy than new coal-fired power stations in most countries.

The stories in this issue of ReNew show the transition is happening already, and communities and the market are leading the way. Now we need government on board to ensure it is fair and equitable and that everyone is brought along on the journey.

At the ATA we continue to provide independent advice to help renters, apartment dwellers and disadvantaged communities. Working with our partners in the social sector we advocate for reform of the energy market to ensure it is of benefit to consumers as well as the planet. Delivering on-the-ground projects in East Timor and to community groups across Australia, we put knowledge into action for a fair and just renewable future.

The ATA cannot solve climate change—no one organisation can—but we can and do empower people like you to take responsible and effective action to reduce Australia’s, and the world’s, carbon footprint.

If you would like to support the work of the ATA, make a tax-deductible donation by the end of the financial year on 30 June. Go to shop.ata.org.au or call 03 9639 1500.

Donna Luckman
CEO, ATA

You can purchase ReNew 140 from the ATA webshop.

An all-electric home can reduce your bills and ‘green’ your energy use, particularly if you run your house from the sun. And, as the grid gets greener, so too does your house. The roof of this Hawthorn, Melbourne extension was designed specifically to house the 4.5kW solar array that powers the house. Design by Habitech; read the full profile in Sanctuary 37.

Three steps to all-electric

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Thinking about going all-electric, but unsure what’s involved? Here we present an overview of the steps to going all-electric and where to find more information.

IN THE past, gas was seen as a cheap and clean option for winter heating, hot water and cooking. However, the efficiency of electric appliances has improved dramatically and solar PV has fallen so much in price (and can be used to power those appliances), meaning it can now be cheaper and more environmentally sustainable to go off gas and run an all-electric home.

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The ATA first looked at this in 2014 and the modelling results can be found at www.bit.ly/ATA-GVE. In summary, the results showed that even when paying grid electricity rates (i.e. without solar PV), for many Australian homes it would be cheaper over 10 years to switch from gas to efficient electric appliances, with appliances replaced as they fail or in some cases even before this. Greater savings can be found when disconnecting completely from the gas network as this eliminates the gas supply charge (costing several hundred dollars a year). The report also highlighted that new homes should not be connected to gas, as doing so would lock in higher energy costs than needed.

Savings will depend on the thermal performance of your home, the electricity price negotiated with your retailer, your gas tariffs and the efficiency of your appliances. The Grattan Institute found that a large home in Melbourne can save $1024 per year by disconnecting from the gas grid: www.bit.ly/GATCAHC

In addition, by using modern electric appliances, your home can be converted to use 100% renewable energy, whether you generate your own electricity with rooftop solar or purchase 100% GreenPower from your electricity retailer. The ATA’s latest modelling compares gas running costs to electric with solar; see p. 44 for preliminary results.

Three steps to all-electric

There are three main areas where many homes currently use gas: space heating, hot water and cooking (mainly cooktops, but ovens too). To switch to all-electric, there are now efficient options available for these uses. This article summarises the options and points to where to find more information.

Read the full article in ReNew 140.

mineral wool packing

2017 insulation buyers guide

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Is your home hot in summer and freezing in winter? It probably has little or no insulation. Lance Turner takes a look at how insulation can help.

Download the full buyers guide tables here.

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Insulation, like orientation, is often overlooked by householders, perhaps because it’s not on display, hidden as it is in the ceiling, walls or underfloor. You may not be able to see it, but, in most homes, you can feel its presence, or absence. Insulation is key to providing a liveable home when the weather cools down or heats up, without breaking the bank on energy costs.

Insulation works by resisting the flow of heat, slowing down heat loss in winter and heat gains in summer. In a well-insulated home, once the home has been heated to a comfortable level in winter, it will stay warm with far less energy input than an uninsulated or poorly insulated home would require.

The same applies in summer: a properly insulated home will take longer to heat up and, if an air conditioner is used, it will use less energy than one cooling an uninsulated house. One summer-time caveat: any windows that receive direct sunlight need to be shaded, particularly west windows, as insulation can slow the ability of the house to cool down if there are large heat gains from windows.

Heat transfer and insulation
There are three ways that heat is transferred to or from a building: conduction, convection and radiation (and through gaps, of course, but draughtproofing is outside the scope of this guide).
Conduction is the transfer of heat through a substance, in this case the walls, floor and ceiling of a house. The type of insulation used to reduce conductive heat transfer is known as ‘bulk’ insulation.

This is the most common home insulation and may be in the form of fluffy ‘batts’ or ‘blankets’ made of materials such as polyester, glass or mineral wool or sheep’s wool. Bulk insulation may also use a loose-fill material, which is pumped into the roof or wall cavities and sealed with a spray-on cap. All these materials are poor conductors of heat and so reduce the rate of heat flow, provided they are installed correctly.

Convection heat transfer—heat transferred through the circulation of air—is the undoing of many insulation jobs. Circulating air can pass between poorly installed insulation materials and thus transfer heat into or out of the house, vastly reducing the effectiveness of the insulation.

Radiation is a different type of heat transfer. All warm objects radiate heat in the form of infrared radiation. This heat can be reflected back to where it has come from using reflective foil insulation, so that heat loss or gain through radiation is greatly reduced.

Reflective surfaces such as foil don’t just reflect, they also have low emissivity—the ability to emit radiation, or heat in this case. This means heat that has entered the material from the non-reflective side is not emitted from the reflective side easily. Thus, foils work to reduce heat flows in both directions, even if only one side of the material is reflective.

Download the full buyers guide tables here.

Read the full article in ReNew 140.

Thermal image post wall insulation

Wall insulation retrofits on trial

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A recent series of trials by Sustainability Victoria has investigated the viability and cost-effectiveness of energy efficiency retrofits. Eva Matthews summarises the overall study and the results from one trial, retrofitting wall insulation.

WHILE residential development (new housing and renovations) continues apace throughout urban Australia and mandatory building standards have been introduced over the last couple of decades to improve energy efficiency and reduce greenhouse gas emissions, there remains a huge pool of older existing housing stock that hasn’t benefitted from these improvements. There have also been few studies to determine the extent of inefficiency in this existing housing, how it might be practically upgraded and how cost-effective it would be to do so. Step in Sustainability Victoria (SV), who commenced a study in 2009 to investigate these information gaps.

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Their On-Ground Assessment (OGA) compiled data, based on modelling, from a “reasonably representative” sample of 60 pre-2005 homes in Victoria, with the results published in December 2015 (The Energy Efficiency Upgrade Potential of Existing Victorian Houses; www.bit.ly/2cTP6eJ). The second phase of the study was to implement energy efficiency upgrades in a selection of houses and to assess costs and savings, householder perceptions and any implementation issues. The results of these trials are also at the above link.

Here we outline the results of the OGA as it relates to wall insulation, focusing on the Cavity Wall Insulation Retrofit Trial, conducted with 15 homes in 2012 and 2013, with results published by SV in January 2016.

Why the focus on wall insulation? Simply, because it is a significant factor in the energy performance of buildings, and millions of older homes don’t have it. Those that do, benefit from a home that is warmer in winter and cooler in summer with reduced need for supplementary heating/cooling due to greater retention of the heat and coolth, fewer draughts, less noise pollution and less condensation on internal walls in winter—the latter inhibiting mould growth which can be a significant health hazard.

Why consider pumped-in wall insulation as the most feasible retrofit option? Unless you’re undertaking a renovation that includes the removal of internal wall linings or one in which weatherboards are to be removed to allow access to the wall cavities from the outside, pumping in wall insulation is the only practical option for existing housing stock.

The OGA found that 95% of the 60 homes in the study had no wall insulation. With 15% to 25% of heat gain/loss being attributed to uninsulated walls, this helps clarify why the average house energy rating of these pre-2005 houses was just 1.81 Stars (significantly lower than the requirement of 5 Stars for post-2005 and 6 Stars for post-2011 homes).

Read the full article in ReNew 140.

SIPs house in Toowoomba

SIPs house in Toowoomba

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Bill and Margaret Curnow’s house in Toowoomba is built using structural insulated panels and is being monitored for heating and cooling energy use by QUT. Dr Wendy Miller reports on the research.

MOST Australian homes are built using timber or steel frames, over which internal and external wall linings and a roof are then added, along with insulation between these ‘skins’. Structural insulated panels (SIPs) present a whole new construction technique: these panels provide the linings, insulation and structural framework all in one unit.

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My research team at Queensland University of Technology (QUT) has been examining how houses using SIPs are actually performing, in terms of comfort and energy use (i.e. heating and cooling impacts), as well as how the homeowners and their designers and builders have managed this new construction method. This research is part of an Australian Research Council project looking at how innovation and high energy performance can be implemented in Australia’s housing industry. Bill Curnow’s house in Toowoomba is one of four SIPs homes in our research. The other homes are located in South Australia, Victoria and Western Australia. Our project also examines performance of homes that have implemented other innovations.

Temperature performance

Toowoomba is in a warm temperature climate zone that tends to require more heating than cooling in houses. There are six months of the year where the mean minimum temperature is less than 13 °C and only two months where the mean maximum temperature is higher than 27 °C. Despite this, temperature extremes as high as 40 °C and as low as -3 °C (or -16.5 °C with wind chill factor!) can occur. Houses should be able to provide some level of occupant comfort under ‘normal’ as well as extreme weather conditions.

We compared the outdoor temperatures for Toowoomba with temperatures in Bill’s living room. In January 2016, Toowoomba’s outdoor temperatures ranged from 19 °C to 34.2 °C, with a mean of 28 °C. In July, the outdoor temperature ranged from 10.8 °C to 24.5 °C, with a mean of 17.5 °C (interestingly, almost 1 °C hotter than the long-term mean for this month).

Compare this with the much more comfortable range of temperatures in Bill’s living room, as shown in Table 1, with January temperatures largely in the range 20 °C to 26 °C and July temperatures in the range 15 °C to 21 °C. This performance with no additional space heating or cooling suggests that the living room is performing equivalent to an 8.5 to 9 Star rating.

Read the full article in ReNew 140.

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Capital improvements: The path to all-electric

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Switching to electric appliances wasn’t really thought of as economically or environmentally beneficial 10 years ago when Ben Elliston’s household started their efficiency improvements, so theirs has been a gradual path to all-electric. By Robyn Deed.

You could call Ben Elliston’s household a ‘poster child’ for getting off gas, but that’s not how it began. Rather, when they started the process to improve the efficiency of their Canberra home 10 years ago, the family’s mindset was aligned with the message at that time that gas was a cheaper and relatively clean fuel, compared to grid electricity. Ten years on and several ‘face-palm-why-did-we do-that’ moments later, they are now enthusiastically all-electric, with their energy use, operating costs and greenhouse gas emissions all pleasingly reduced—and with some added advantages of their new electric appliances that they didn’t expect.

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Looking back, Ben says one of the biggest shifts has been in what a state-of-the-art electric appliance looks like. From the simple electric element appliances of the 80s (the coil cooktop, electric blow heaters and electric element tanks), many of the newer appliances offer not only lower running costs—over both gas and older electric units—but also safety and other benefits. Ben says, “There were lots of advantages we hadn’t anticipated when we shifted to electric appliances. For example, our induction cooktop has smarts to switch off if it senses that a pot is too hot and has run dry; our heat pump air conditioner is also much quieter than our old gas wall heater.”

The other major factor for Ben’s family is environmental. With the ACT now well on the way to 100% renewable electricity by 2020, Ben says, “In 2020, our household will be net zero emissions, which would not be possible if we were still using any gas appliances.”

Read the full article in ReNew 140This article is based on a talk given by Ben Elliston at the ATA’s Canberra branch meeting in April 2017 and an interview with Ben. Click here for slides from the talk.

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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.

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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!

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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?

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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?

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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.

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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.