In ‘Sustainable houses’ Category

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ReNew 143 editorial: not just window shopping

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

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Depending where you live, it seems that different sub-floor structures are in vogue. For example, in Queensland in descending order of prevalence are full concrete slabs, timber floors and waffle pods, whereas in the ACT it’s waffle pods that make up the majority of builds, according to 2016 analysis from CSIRO (www.bit.ly/2Fwzls9). We look at all of these floor designs and consider their sustainability credentials, highlighting some excellent resources along the way.

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

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

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

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

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

Robyn Deed
ReNew Editor

ATA CEO’s Report

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

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

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

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

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

CEO, ATA

You can purchase ReNew 143 from the ATA webshop.

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Window and film buyers guide

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

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

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

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

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

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

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

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

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

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

Read the full buyers guide in ReNew 143.

Download the full buyers guide tables here.

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The right floor for your build

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

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

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

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

Flooring requirements

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

The floor’s footing system must be suitable for the type of soil you have on your block. A soil report will be required which will tell you your soil type and how reactive it is. Reactive soils are soils with a high clay content which swell when wet and shrink as they dry. This expansion and contraction can cause structural cracking, sinking and other site issues. See www.bit.ly/2oKu9GC for a quick rundown of soil types.

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

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

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

Read the full article in ReNew 143.

Download the summary tables here.

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Living Building Challenge in Castlemaine

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

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

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

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

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

Read the full article in ReNew 143.

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Material beauty

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

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

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

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

The advantage of using an architect

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

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

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

Read the full article in ReNew 143.

Double-glazed windows waiting to be installed

Glazed and enthused: Window replacement case studies

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

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

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

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

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

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

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

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

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

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

Fitting secondary glazing

Doubling up: Secondary glazing case studies

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

Film + DIY secondary glazing
by Jasper Lee

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

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

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

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

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New glass is greener: Retrofit double glazing case studies

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

Retrofit double glazing by Thermawood
by Carolyn Nguyen

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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ReNew 142 editorial: to boldy solve the split incentive

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

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

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

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

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

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

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

Robyn Deed
ReNew Editor

ATA CEO’s Report

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

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

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

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

Donna Luckman
CEO, ATA

You can purchase ReNew 142 from the ATA webshop.

Rental house

Landlords leading the way

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

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

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

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

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

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

Read the full article in ReNew 142.

Energy Efficiency Scorecard assessment

Scoring your home

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

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

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

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

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

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

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Induction cooktop mini guide

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

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

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

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

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

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

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

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

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

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

Featured image: Samsung

Read the full article in ReNew 142.

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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.

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Towards grid independence

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What happens when a home with very low electricity use adds a battery? Terry Teoh describes his home’s interesting results.

OUR house is an Edwardian three-bedroom brick home renovated in 2010 along sustainable design lines. With two occupants, our house achieves a very low average electricity consumption of 2.4 kWh/day, though note that gas is (currently) used for space heating, cooking and boosting of solar hot water.

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We installed a 5 kW solar PV system in December 2016. With the array oriented east and west, the seasonal difference in energy production is accentuated compared to a north-facing array: our system produces on average 26 kWh/day in summer and 7 kWh/day in winter.

In April 2017, we added a 4 kWh Sonnen eco8 battery to our system to provide solar load shifting—storing solar energy produced during the day for use at night.

In the first two months of operation (to June 2017), our house has moved from 30% to 70% grid independence—i.e. 70% of our energy is now generated by our solar system.

Interestingly, that 70% is lower than we expected given a substantially oversized solar array and battery. It turns out that our standby energy usage is too low to be served by our inverter!

However, it’s still a good result and the battery has lifted solar self-consumption from 5% to 50% and paved the way for us to disconnect from the gas network and move to an all-electric, renewably powered household.

Motivations
Our motivations for installing a battery system included a desire to maximise solar self-consumption and grid independence. The latter is not out of antipathy for energy companies or the grid. We want to stay connected to the grid.

The grid is good; it will just be used in a different way in the future to support a decentralised energy system where consumers will have more control over how they make, use, store and share energy.

Read the full article 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.

Desert Rose render

A net zero energy home

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A net zero energy home for desert conditions is the mission of the next international Solar Decathlon, but the University of Wollongong’s entry could have applicability far beyond the competition.

The University of Wollongong’s entry in the next international Solar Decathlon is perhaps aptly named. It’s called the Desert Rose, after a plant that can cope with the tough conditions the team will encounter when they build and operate their sustainable house design in the host city, Dubai, in November next year.

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With temperatures of 35+°C every day, less than 2 mm of rain for the month and desert sands that present problems for both greenery and solar panels alike, there are certainly challenges ahead.

Student-led sustainable innovation
What is the Solar Decathlon? Sometimes called the Energy Olympics, the decathlon was started in 2000 by the US Department of Energy to encourage innovation in sustainable, renewably-powered residential buildings.

The contest challenges university student teams to not only design, but also build and operate a home that produces more energy than it consumes—a net zero energy home.

The University of Wollongong (and Australia) first competed in 2013. Amazingly, that entry, the Illawarra Flame (www.illawarraflame.com.au/house.php), won with the “highest score ever recorded,” says a suitably proud Brendan Banfield, building services manager for the 2018 team.

It’s a crash course in construction for the student competitors. The houses they design get built, dismantled and rebuilt, perhaps many times over the course of the competition.

In 2013, the Illawarra Flame was built and dismantled twice before its journey in seven 40-foot containers to that year’s Chinese host city. It took 12 weeks to build the first time (in a warehouse in Wollongong), but then just five days to dismantle and ten to re-assemble on site in China.

It’s an undertaking that gives the student competitors—from diverse fields including engineering, architecture, health, arts, business and communications—incredible hands-on experience in design, construction and problem-solving.

In fact, a US Department of Energy survey (covering four solar decathlons from 2002 to 2009; see www.bit.ly/2jgguaf) found some 76% of past competitors went on to jobs in the sustainable building and clean energy sector, compared to just 16% of non-competing fellow students (and 92% found the competition critical to their job-seeking).

Brendan says, “The technology used or invented is typically five years ahead of the market and 10 years ahead of the building code, giving competitors an ‘edge’ when seeking work or starting a business”—some 16% of those surveyed had started their own sustainability business as a result.

Read the full article in ReNew 141.

Read more about the Desert Rose team and their entry here.

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.