The Sydney Sustainable House is a 19th century three-bedroom terrace in Chippendale that was first renovated in 1996 by its owner, environmental consultant and lawyer Michael Mobbs.
His initiatives included the installation of 18 solar panels, each with 120-watt capacity, which reduced the building’s energy needs from the grid by more than 60 percent. Mobbs’ family also began collecting rainwater in an 8,500L concrete tank, and recycling it into drinking water.
According to his website, this is achieved by using a ‘first-flush’ device, which directs the first dirty rush of rainwater from the roof, as well as a sump and self-cleaning gutters.
In 2015, almost a decade after the first revamp, Mobbs disconnected his residence from city power and went completely off-grid. Adding 12 more solar panels, the house’s total system capacity is just over 3.5kW today.
“I set out to renovate my inner-city Sydney terrace and make it almost entirely self-sufficient in terms of energy, water and waste disposal. It was a journey few other Australians had attempted but I've shown it can be achieved and that it's possible for almost anyone,” Mobbs writes on his site.
“Then I realised that although my house had become sustainable, I still wasn’t. While my home saves 100,000 litres of dam water a year, the same amount of water is used to produce ten days’ worth of food for the average Australian. So, I turned my attention to reducing the pollution and resource use associated with growing, processing, transporting, selling and disposing of food.”
The eco-friendly transformation significantly reduced the family of four’s energy and water bills to less than $300 a year—a figure that hasn’t increased over the last two decades.
According to statistics provided by Canstar Blue, this is over five times less than the average household electricity bill across Australia.
RETROFIT VS BEHAVIOR CHANGE
If there is one lesson architects can take away from Mobbs and his Sustainable House project, it is that technical and design sustainability, together with end-user passion, creates the best results. Educating clients and building occupants is fundamental to a sustainable alteration or addition being successful.
This is supported by a 2017 CSIRO paper, which found that the most effective way to reduce a household’s energy consumption is through a green retrofit, complemented by behavior change interventions.
The study carried out a randomised control trial that compared changes in energy consumption in 320 low-income Victorian households. The results showed that households that were renovated only saw total energy consumption fall by 7.1 percent, while households that underwent behavior change-only interventions did not show any noticeable improvements.
Meanwhile, households that combined both technical and behavioral changes reduced their gas consumption by 18.6 percent, and total energy consumption by 11.4 percent.
Michael Mobbs. CC BY 2.0 — image by Nicolas Boullosa.
“We theorise about people’s interest in sustainability but, and God help us, the market can now give us the verdict on that assumption,” Mobbs told Domain, speaking about his desire to rent out his home for over 20 years for $1,500 a week.
“Are people really interested in a place where you can live without polluting the ocean or air and damaging the environment? We shall see …”
Read more about the Sydney Sustainable House project and Mobbs’ insights on his blog.