‘Energy efficient’, ‘carbon neutral’ and ‘net zero’ are buzzwords we hear more and more as we face the impacts of climate change. But do we think about it enough during construction?
The movement towards sustainable housing is growing worldwide. In Europe, efforts to move towards greener homes hope to combat rising energy costs and be better for the planet. But 40% of global CO2 emissions still come from the real estate sector.
In Australia, off-grid electric homes are becoming increasingly common. A recent report from the University of New South Wales is encouraging the built environment to reach net zero by 2040, and according to a 2024 study from Domain, energy-efficient properties are attracting more interest than conventional homes.
But even if net-zero homes – meaning your home emits no net carbon emissions – are not yet the norm, many architects are starting to champion sustainable design, aiming for high energy ratings and future-proof homes to adapt to the changing climate.
By reducing their carbon footprint and using passive design – which focuses on conditions such as sunlight and layout rather than artificial climate control – these net-zero homes make it clear that going back to basics is the key to making the switch.
Huff’n’Puff Haus, Strathbogie Ranges, Victoria
Once upon a time there was a big bad wolf who could blow, blow and blow the straw house. But not anymore: In rural Victoria, Envirotecture’s Huff’n’Puff Haus is here to stay.
Asked to create an off-grid, all-electric, energy-efficient home, architect and director Talina Edwards decided to build a home where two empty nesters could age in place for years.
The Huff’n’Puff house is made from prefabricated, structurally insulated straw bale panels approximately 300-350mm thick and has a ‘passive house premium certification’, meaning it generates more renewable energy than it consumes.
As a waste product, straw not only captures CO2 – reducing carbon in the project – but is also an underutilized material in construction. Edwards says the amount of straw burned in paddocks each year would be enough to insulate 40,000 homes in Australia each year.
Envirotecture also aimed to use sustainably sourced wood, reduce the use of plastic during construction and focus on a good ventilation strategy for healthy air quality. The house hardly needs heating and cooling, but depends on orientation, cross ventilation, passive sun protection and natural light.
“The cost to build something is expensive, but not the cost to build well,” says Edwards.
“If you reduce the size and maybe don’t have as much built-in joinery, you can choose how you prioritize.”
Despite Australia’s ‘obsession’ with large houses, the 200 square meter house is flexible and functional: a corridor opens into spaces rather than entire rooms. A breakfast bar can become a study area; a window seat, a place to look at the view.
“On a regional site it always looks a bit strange when you have a small house, but we have kept it modest,” says Edwards. “I think this is the first tip for anyone building anywhere.”
The project has won many awards since its completion and has been shortlisted in the sustainability category of the House Awards. But for Edwards, it’s not about accolades.
“Everyone kept saying, ‘It’s so beautiful… but it’s not about what it looks like,’” she says.
“…Its beauty goes beyond skin deep. What is hidden behind it? What is the true core of what this does?… It is honest beauty, not just taking into account the aesthetics.”
39S House, Brisbane, Queensland
On a 240 square meter block in Brisbane, architect Andrew Noonan has breathed new life into a dilapidated Victorian-era timber cottage, giving the five-bedroom family home a net zero future.
In pursuit of a lifetime net zero home – one that removes as much carbon from the system through energy production and materials as it takes to build – Noonan went back to basics and applied passive design principles to literally house around.
“The house originally ran from north to south. It had a very long west-facing facade,” says Noonan.
“100 meters away is Suncorp Stadium… and a main road, so quite noisy on that same west side… it became a great opportunity to take one big step to solve a few problems.”
Noonan removed a 1930s addition to the rear of the house and added a new extension to achieve an east-west orientation. It’s a five-bedroom house, four of which are occupied, but Noonan says the necessity should be questioned when building it.
“Do we all need media rooms? Do we all need three, four or five bathrooms?” He says the key to the net-zero approach is that climate dictates the choice of materials to ensure a lifespan of more than 55 years for a home.
If you have high-quality doors and windows, “they will last far longer than the life of the building,” says Noonan.
“If they are made in a way that is designed to be thermally efficient – not cheap one-piece aluminum frames with very thin glazing in them… but something that thinks about performance – that will have lasting value.”
39S House also has no heating or cooling, instead relying on heavily insulated truss construction and orientation to accommodate Brisbane’s humidity.
And while Noonan recommends electrifying everything by switching to induction equipment, air source heat pumps and buying photovoltaic panels – which are different from solar – he says gadgets “won’t solve the problem if it isn’t solved in a simpler way first.” dissolved” .
Green space covers 50% of the site, reducing external heat. The air temperature directly outside the doors and windows is 15 degrees cooler than if the area were paved without trees.
And the house also takes into account Brisbane’s tendency to flood, by raising the house above the ground and absorbing flood water into the soil, slowing runoff downstream.
“Just because it’s doing some really interesting sustainability work doesn’t mean it has to look like a tree house,” says Noonan.
“It can look like it looks like any house…the aesthetic doesn’t really match the execution.”
Farrier Lane House, Perth, Western Australia
Architect Matt Delroy-Carr wanted to build an affordable, high-performing family home. But when a life cycle assessment showed carbon neutrality midway through the project, he added net-zero status to the list.
His home, Farrier Lane House, now serves as a sustainable building demonstration project for his practice MDC Architects.
“A 1,800-square-foot house can have exactly the same things as a 1,400-square-foot house like mine,” says Delroy-Carr. “It only has 40 square meters of wasted area that is inefficiently designed.”
Farrier Lane House has large windows to open up the space. The house-to-garden ratio strongly favors green space, which fills 60% of the surface area to increase the livability of a house with a smaller footprint.
Inside, it has a double brick ground floor, providing solid thermal mass, a hybrid upper floor with inverted brick veneer and timber-framed floors throughout.
But Delroy-Carr often says that the more you focus on carbon neutrality through material use, the harder it is to get a high NatHERS star rating.
“The classification system heavily favors masonry structures… it likes brick and concrete because they are high thermal mass materials,” he says.
“The more concrete and bricks you put into the project, the higher the star rating, but inevitably, the higher the ecological footprint.”
Although we are creatures of habit, Delroy-Carr says younger generations are becoming more focused on sustainability and a smaller footprint. But his advice to clients is: “Don’t try to do everything.”
For him, the first thing to try is orientation. Even if the MDC homes are outside the plan, they are all intended to face north.
Beyond three things – carbon footprint, thermal performance and livability – co-existence, responding to your climate is of paramount importance and something you can do on a modest budget.
“That’s our basic design philosophy…you don’t have to spruce up a home with too many additions to make it comfortable.”