Ben Boyd Road House sustainable homes
Ben Boyd Road House

The full spectrum of low-impact, low-carbon homes – everything from new builds through to eco-upgrades to existing dwellings – will be on show this Sunday for the Alternative Technology Association’s nation-wide Sustainable House Day event.

Around 250 properties are participating, showcasing features such as renewable energy, use of recycled materials, exemplary energy-efficiency, climate-resilient and edible gardens, and passive thermal comfort techniques.

“Sustainable House Day is a great opportunity to come and learn how to make your own home more comfortable, more liveable and cheaper to run,” ATA chief executive Donna Luckman says.

“A home that works – that’s well-designed, healthy and runs efficiently in an age of high energy costs – is what everyone wants. That’s what people will see on Sustainable House Day this year.”

In Sydney, two homes designed by leading sustainable design practitioners Envirotecture highlight the way design can deliver green outcomes on any budget – even when the homeowners may not be overly passionate about environmental matters.

One of the projects, the Ben Boyd Road House in Neutral Bay, was a “knock down rebuild” project with a contract budget of $1.2 million.

Envirotecture principal, Dick Clarke, told The Fifth Estate this was quite a modest budget for that part of Sydney, where high land prices make it almost “impossible to over capitalise” spending on the home.

“Most people in the area are spending twice that or more on a new home,” he says.

The clients were clear that they were “not greenies”. What they did want was a comfortable home with low energy costs, Clarke says.

Clarke points out this position aligns perfectly with a sustainable design approach and makes them “economically greenies”.

The home combines passive design including orientation, the use of thermal mass, insulation (including slab insulation), shading, double-glazing, evacuated tube solar PV, and solar tube hot water that also supplies an in-slab hydronic heating system.

Overall, good quality, long-lasting finishes were used.

Bricks reclaimed from the burnt-out bungalow that was demolished on the site were re-used, along with recycled aggregate, recycled concrete and recycled polyester insulation batts.

One of the challenges was the neighbouring property shading the northerly aspect of the home “more than we would have liked,” Clarke says.

Notwithstanding the orientation challenges, the home is estimated to be saving the owners $3500 a quarter in energy costs.

Clarke says he also made a bet with the client that if they decided to install air conditioning, they would actually never use it more than once.

It was only turned on twice that he is aware of, Clarke says, and one of those occasions was probably to test it worked. Otherwise, even during last summer’s extreme heat, it was not necessary.

“I think it is probably the most sustainable house in the Lower North Shore,” Clarke says.

In general, Clarke says he is seeing more awareness of sustainability in the market.

“People might not understand building physics, but they do generally understand the importance of insulation, orientation and shading,” he says.

There’s also some people in the market who are well-informed on sustainability and extensively read on the subject, like his clients for The Paling House in North Ryde, also on show this Sunday.

Clarke says they had a different motivation to the Ben Boyd owners – and they wanted a sustainable home that was also low energy and high on thermal comfort.

The existing dwelling was a typical “houso” asbestos fibro state-developed housing property.

Clarke says they didn’t want to knock it down and rebuild like most owners of similar properties in the area.

“That type of a house is a valid part of Australia’s social history,” Clarke says.

What they did want was a home with a “clean bill of health”, which means getting rid of the asbestos fibro.

The Paling House

Clarke says that any similar property basically sells for land value minus the demolition cost. And whether the owner decides to renovate and remediate or knock down and rebuild, the cost of asbestos removal remains the same.

For the Paling House, that was around $15,000.

Orientation in the existing home was all wrong for maximising northerly aspects for living areas, so these rooms were turned into a bedroom wing. A new living and kitchen area with a northerly aspect was added to the rear.

In total, the project cost around $272,000. This included fully insulating both new and old parts of the home, asbestos removal and replacement of the fibro with carbon-negative magnesium oxide board, sourcing and installing recycled fence palings and rusty COR-TEN steel for external cladding, upgrading windows to double-glazing and incorporating louvres for ventilation, installing shading such as blinds and awnings, a new and water-efficient bathroom, and automated systems for blinds and louvres.

Clarke says the project was able to minimise the materials used by recycling materials and also by retaining the existing timber frame of the “houso”.

The legacy fibro homes around the country actually represent some good opportunities for renovation and remediation.

“We love them when we come across them.”

Clarke says there are clients like the Paling House owners who are both educated and aware of the risks of asbestos and “don’t have fear or paranoia” about it.

These home owners, who tend to be between 30 and 50 years old, “understand the potential with renovation.”

One of the big advantages of a classic 50s fibro is it inevitably has a frame that is “solid and straight hardwood,” Clarke explains.

“That is a terrific starting point.”

The style of frame also means the home is easily altered to increase solar orientation, as adding windows if required or shifting internal wall configurations is easily done.

“There are often good bones inside and it lends itself beautifully to [adjusting] the orientation.”

He says that over the past 20 years, his practice has “rescued” around 10 of these types of homes from demolition.

“That is not as many as we would like to have rescued.”

Building for extreme heat in Adelaide

Designing and building a home that would be comfortable in the extremely hot South Australian summers was the priority for the Mark Clayton and Karina Deans, owner-builders of the Climate Ready house in Glanville, South Australia.

The home was completed in April 2018, and currently its 6.2 kW grid-connected solar PV has been generating three times the energy the home uses.

This is despite the home being situated on what they describe as the “worst oriented block” in the area. It has a narrow northerly aspect, and extensive west-facing aspect.

The home was rated at 8.2 Stars via First Rate, and cost $240,000 to build.

A combination of lightweight structural insulated panels, steel framing, timber and reverse brick veneer was used.

Double glazing combined with blinds and deciduous vegetation for shading help prevent heat entering the home in summer.

It has no air conditioning. Instead, there are ceiling fans for air movement and a wood fire for winter heating.

Tiny homes with big credentials

This year has seen a substantial number of new tiny house projects joining SHD.

They include homes that are designed to stay put and make the most of a small site, such as the Geelong tiny house developed by Manage Carbon principal, Vicky Grosser.

There are also multiple transportable tiny homes, including the Brisbane Tiny House Company’s $45,000 LINX model, a 24 square metre home with solar PV and composting toilet that can be adapted for off-grid living.

Another Queensland participant is The Tiny House Company, which is opening the doors of its Swallowtail model in Salisbury. The 18 square metre home with a starting price of $79,000 is on a trailer, and is fully-insulated, including roof, walls and floor.

The company aims to provide a flexible home that can incorporate a range of spatial configurations, extras and upgrades.

In Kinglake, Victoria, Tiny Footprint is opening three tiny homes including a fully-accessible home suitable for occupants with mobility restrictions, a tiny chapel on wheels and a fairly luxe transportable tiny home model, the Mayflower.

The Mayflower costs up to $130,000 and comes with most of the mod-cons of an up-market sustainable apartment. This includes full-size gas kitchen appliances, ceiling fan, windows and skylights for light and ventilation, composting toilet, grey water system and insulation to roof, walls and floor.

The Cape rolls out the green carpet

Uber-green masterplanned sustainable community on Victoria’s Bass Coast, The Cape, will be showcasing the full gamut of sustainable community innovations.

In addition to inspecting five open homes including the 10 Star House by Sociable Weaver and four other new properties with ratings of 8 Star or higher, visitors can take a tour of the community garden, take a ride on an electric bike or test out a Nissan or Tesla electric car.

There will also be a street party, pizza, and presentations by architects, builders and sustainability experts.

Tony O’Connell, director of TS Constructions, which just completed the CORE 9 house that will be open on the day, tells The Fifth Estate that “getting the design” right is the most important part of delivering a high-performing home.

“You can put a lot of products in [a home], but if you get the design right, you don’t have to trick the house up,” he says.

Passive design techniques such as optimum solar orientation and use of thermal mass can actually get a home to six stars, he says, even without adding double glazing or extra high-spec insulation.

Other design methods include minimising passages to avoid the “rabbit warren” effect in homes, while also assisting with cross-flow ventilation.

By putting design first, he says it is possible to achieve a more sustainable home at a more affordable price.

“I think sustainable should also mean affordable,” O’Connell says.

He says his aim is to get the highly energy-efficient and thermally comfortable results “without going overboard” with costly products and extras.

“I wanted to keep [sustainable homes] mainstream.”

In addition to good design, the CORE 9 home has 6 kW of solar PV and a 4.8 kW/hr battery that services the solar hot water and the evening load.

“So you’ve got a home with virtually zero power bills.”

  • Register to attend Sustainable House Day and view the profiles of this year’s homes here

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