Improving sustainable home design

Chiara Pacifici says a major impediment to the adoption of sustainably designed homes is the perception that such builds come with a high price tag.

It’s a belief she disputes.

A real estate agent and sustainability consultant, Ms Pacifici established Green Gurus in 2009 to educate and consult on better housing design, and to inspire people to seek out sustainable housing choices.

Designing and constructing buildings of this nature is pivotal in the development of homes that can withstand time, preserve the natural environment, and save resources and money through energy efficiency.

Backed by her more than 25 years’ experience in property, Ms Pacifici founded Green Gurus at a time when sustainable design “wasn’t really a thing”.

“Green Gurus has been chipping away at that educational need for nearly 15 years now with the support of amazing leading Western Australian property specialists who collaborate with us and are great advocates for positive change in the built form,” Ms Pacifici told Business News.

Despite improved understanding and implementation of sustainable design, Ms Pacifici said there was still a long way to go to make this a priority.

She said the assumption that sustainable design was expensive must be debunked.

Cost shouldn’t be any greater than for non-sustainable builds, Ms Pacifici said, given many design principles were already required to meet the current mandated six-star energy efficiency rating set by the National Construction Code.

“In the past five years, the state and federal planning departments have started to change policy to ensure environmentally sustainable design, or ESD, is incorporated in new builds,” she said.

“Building codes have gone from four star in 2005 up to six star in 2011, and now seven star is to come in May 2024, which is going to create much more comfortable homes to live in.”

Residential buildings designed to avoid unnecessary energy consumption are ranked with a high star rating by the Nationwide House Energy Rating Scheme (NatHERS).

ESD utilises design principles such as orientation and building materials to mediate the temperature of a house without using air-conditioning.

“Orientation is vital, and if you get your main living areas facing north, you’re halfway there,” Ms Pacifici said.

“[N]ot all blocks can be facing north, but there are ways of optimising lot orientation.

“Next, you’ve got house design and building material selection. You should design the building with cross-flow ventilation to bring that ocean breeze through the house to cool it and get heat energy that’s stored in the peak of summer out.

“And then the building materials work to lock in that heat energy during winter.”

Green Gurus has been educating people on the benefits of retrofitting existing houses as an inexpensive and viable sustainability option.

“With the national construction codes it doesn’t have to be a brand-new house,” Ms Pacifici said.

“You can do a renovation or extension that meets the six-star requirements.

“Unfortunately, 98 per cent of Australian housing stock is functioning at a two- or three-star rating, so we’ve got a lot of work to do with retrofitting.”

In conversation with Business News, Ms Pacifici said converting an inefficient two-star house to bring it up to a six- or seven-star rating would create a more energy-efficient home, while also increasing the home value for any future sale.

“And retrofitting is easy,” she said.

“You can do it for $10,000 or $15,000 for a simple 120 square metre, three by two.

“Some people think it costs more than it actually does, but it’s not linear; it depends on what you do to a house.

“There are four or five things you look at upgrading, including the two main energy guzzlers: hot water and heating and cooling.

“Regenerative development and building resilience are the two focus areas for adaptation planning to strengthen our housing stock for the future.”

OneOneFive Hamilton Hill is one of DevelopmentWA’s sustainable developments. Photo: DevelopmentWA

DevelopmentWA has been focused on leading better housing design by setting the bar for sustainable builds through its projects.

Acting chief executive Dean Mudford said the state government development body had a unique capacity to design and develop projects to shape WA.

“DevelopmentWA is committed to delivering its Net Zero Transition Plan to reach net zero between 2040 and 2050, and building approaches outlined in our Innovation Through Demonstration program will help meet these targets,” Mr Mudford told Business News.

Construction of the OneOneFive sustainable development in Hamilton Hill is under way, with 300 dwellings ranging from single residential to group housing and townhouses.

Mr Mudford said OneOneFive was regarded as the future of sustainable design and was an excellent example of DevelopmentWA’s approach to sustainable housing.

“OneOneFive is being developed on the former Hamilton Senior High School site, with 96 per cent of all materials from the demolition of the old high school being recycled and 86 per cent reused in the new development,” he said.

“The development has been awarded all six leaves in the EnviroDevelopment program by the Urban Development Institute of Australia, is recognised as a Platinum Waterwise Development by Water Corporation, and is a winner of the 2021 Waste Sorted Awards for commitment to resource recovery.

“The use of alternative materials, energy sources and water, as well as the implementation of efficiency measures at OneOneFive, will lower carbon emissions from the development and reduce reliance on large-scale infrastructure.”

Sustainable design principles at OneOneFive include: recycled construction materials; electric power instead of gas; climate-responsive planning to mitigate heat energy; water-sensitive landscaping; rainwater storage; retention of existing vegetation in public open spaces; and increased canopy cover for streets.

The dwellings are designed to meet a 7.5-star NatHERS energy rating and feature solar panels for energy generation and electric vehicle charging amenities in carports.

Mr Mudford said OneOneFive explored alternative built form design to address affordability and liveability.

“The first stage of development will include two compact homes and timber-framed town homes that promote climate responsive design, reduce energy consumption and achieve net zero energy ratings,” he said.

“Innovative building design allows for the surrounding green spaces to flourish and will help to increase tree canopy in suburbia, which is key for reducing temperatures in housing estates and provides opportunity for biodiversity.”

Victorian developer Grange Development Consulting’s proposal to build the world’s tallest hybrid timber tower in South Perth was approved in September, with the development slated to set the benchmark for carbon-negative design. 

The building will be comprised of 237 apartments across its 51 storeys, with 42 per cent of its structure being made of timber.

Grange Development founder James Dibble said just 600 seeds would be used to produce 7,400 cubic metres of mass timber for the development, which would regrow after being used.

“We are providing an open-source blueprint that utilises hybrid construction methodology to offset he carbon within our built environment, which is now the single biggest contributor to climate change in the world at thirty-nine per cent,” Mr Dibble told a Metro Inner-South Joint Development assessment meeting.

Ms Pacifici said the timber tower demonstrated what could be done in the sustainable design space.

“They’ve been really intense with their assessment of carbon footprint, and it’s probably one of the best reporting, measuring and deliverables for ESD I’ve seen,” she said.

“It’s definitely going to be a leader in this space.”