Sustainability has become a hot topic over the past decade. Even more so over the past couple of years with the increases in the NCC and BASIX, it certainly has had people talking. With Australia committing to net- zero emissions by 2050 and the impending federal election, climate considerations are front of mind for many voters.

We spoke with three HIA members, all winners of the 2024 HIA Australian GreenSmart Awards, about their passion for sustainable building, hopes for the future and tips for achieving high-functioning comfortable homes.

Canberra-based Jenny Edwards, Managing Director and Lead Scientist of Light House ArchiScience shared the HIA Australian GreenSmart Home and HIA Australian GreenSmart Custom Built Home awards with 360 Building Solutions.

Jenny’s award-winning project, Oska’s House, uses both passive solar principles and NatHERS energy modelling. With a relatively modest footprint, the home wowed the judges with its incredible efficiency as well as its function and flow.

There’s undoubtedly some ‘Jenergy efficiency’ at Light House ArchiScience. She’s a well-respected advocate and educator in this space, and her hometown is the perfect location for a sustainable focus. ‘In Canberra, our winters are icy, and our summers are searingly hot,’ she says. ‘Heating can make up to 60 per cent of energy bills. That makes this the perfect city to combine the focus on comfort and sustainability.’

Combining creativity and comfort is also high on the agenda for Bruce Millican, Managing Director of Millwood Homes SA. His Adelaide Hills project won the Sustainable Home award at the recent HIA Australian GreenSmart Awards. Built on six sprawling hectares, the family home is off-grid.

‘We need to think first about two factors – self-sufficiency and creating a place the family could grow comfortably,’ says Bruce. The design included a 15kw solar PV system, Pylontech lithium batteries totalling 21kw storage, and a plumbed 130,000-litre rainwater tank to supply the house and garden.

Likewise, Sydney builder Nick Sowden of Sowden Building Solutions specialises in the Passivhaus method. He took out this year’s HIA Australian GreenSmart Renovation/Addition Project Award. The relatively small home was intelligently transformed using sustainable building practices. ‘The renovation wasn’t simple,’ Nick explains.

‘The rear half was demolished to remove a thermal bridge; internal walls were removed to create a more practical flow.’ A third floor was also added to create a master suite taking in city views. Options such as air tightness under 1ACH @ 50pascals, heat recovery ventilation, improved insulation, finishes with low or zero VOC and new energy-efficient fittings have assisted in raising the standard of living in this house.

The owners of this award-winning dwelling have experienced a temperature variation of just five degrees year-round. ‘It makes the home a place you want to be for many years,’ says Nick.

Part of his building story was a desire to live in a healthy, comfortable home that wasn’t prone to dampness, mould, cold and dust. He says this goal would change people’s lives — something you can’t put a price on.

When considering thoughts on the future of sustainable building, all three are passionate about continuing to positively influence understanding and conversation.

According to Jenny, the industry needs to address the size of Australian homes, which are the largest in the world. ‘Good design means projects can have much smaller footprint than a typical home but still feel spacious and function beautifully.’

'If we're serious about sustainability and, of course, affordability, then making a house smaller is essential. Using less materials is better for the environment. There are reduced upfront costs and massively reduced running costs,’ she says.

Jenny, who has moved her business away from new builds towards renovations, sees enormous potential in reconfiguring existing housing stock rather than doing knockdown rebuilds. ‘A lot of them have the potential to be turned into two homes in one,’ she says. ‘We've done a few projects like that which, of course, helps with sustainability, affordability and the housing crisis.’

For those who are concerned about costs, her answer is one of considered balance. Jenny’s big message is: ‘While things such as double glazing can be expensive, insulation is relatively not, and good design can make all the difference.’

On the conversation on products, Bruce is inspired by materials he has personally seen in Europe, but there are local solutions. Jenny agrees, pointing to materials such as Weathertex cladding. ‘It’s a fantastic Australian product made in Newcastle,’ she says. ‘Reconstituted timber has great green credentials and is incredibly cost-effective.’

Bruce also is encouraged by the many builders who are coming up with clever designs. Jenny and Nick are both heartened by the young trades who are aware there are better ways of building. ‘I have guys coming to work for me because they know this is what I do. And they want to learn,’ says Nick. 

Jenny believes things can move quickly with the new generation. ‘We know how to do this now, so be optimistic and aim high,’ she says.

In his acceptance speech at the HIA Australian GreenSmart Awards in Hobart, Bruce included a valuable reminder to young builders: ‘The most important part of a house is the people who are going to live in it.’

For him, nothing rivals the satisfaction of building a home that clients will fall in love with and the peace of mind that comes with it, and there needs to be a touch of awareness with the sustainable building conversations. ‘We must ensure the government and the industry have fully grasped the weather extremes Australians are experiencing now and will be in the future.’

Nick agrees and believes maybe building a standard for energy and comfort needs to be established and a pathway set to achieve it in around 15 years. ‘Then we know what that goal is, so we can start adjusting our training for that,’ he says. ‘Then when we're training whoever's coming through as trades and architects and designers, they know what they're going to be building or designing, and all the supply chain knows the end goal.’

All three agree that one basic factor is ensuring a home is airtight, which can be achieved simply and cheaply by sealing gaps in doors, windows, junctions between floors, walls and ceilings, and even in downlights. Perhaps some people in the industry aren’t fully aware of the significant role this plays in thermal and acoustic comfort.

Jenny believes the key to a 7-star rating really goes back to the basics of orientation and good design – essentially don’t try and make the same 6-star home design into a 7-star home. In most instances this will be the most difficult and costly approach. Design to suit the site and orientation, and apply solar passive principles from the outset.

Bruce sees new houses being built that could be more efficient. ‘Education is key, as well as collecting more data and evidence, such as case studies of homes built to a certain standard that show the energy-consumption rate over a period.

'I've travelled the world, and I’m inspired by what happens globally. Australia's still got a long way to go but with continued focus, we can get there,’ he says.

As for Nick, he feels intelligent choices, as seen in all three of these projects, is what we should aspire to. But he attests to one principle that all three have in common. ‘A sustainable home is better for the country but at the heart of it, considered building needs to make it a place that’s healthy, owners love to be in, a place they want to stay and experience for many years.’

First published 13 January 2025