Sustainability Victoria

Sustainability Victoria is a government-appointed agency working to create a thriving and sustainable Victoria. They exist to promote a circular, climate-resilient economy. They offer a range of tools and services to support partner organisations in achieving net-zero carbon emissions.


Design a tool to calculate the energy efficiency of new homes - inside and out

In Australia, energy efficiency ratings only account for the outside of a building. Zero net carbon (ZNC) homes also measure emissions from appliances like A/C and lights. They offset their consumption with solar energy and provide a fuller picture of ‘lived-in’ energy efficiency. Sustainability Victoria engaged Conduct to design a simple, online process for ZNC accreditation. The goal was to facilitate the process for volume home builders.

Adding zero net carbon to existing energy efficiency assessments

Volume home builders are companies that construct a large number of homes from existing designs. Thermal performance assessors are accredited professionals focused on measuring the efficiency of building shells. In this pilot program, Sustainability Victoria wanted to look at sustainably-designed homes that factor in daily energy use – like people cooking and showering. The idea was to help volume home builders draft (and market) designs for new homes that met the Zero Net Carbon Homes program standard from the outset. This is where the Zero Net Carbon tool came into play – it would calculate the energy use of the home’s fixed appliances like lights and heating to help the design gain a zero net carbon ‘pass’ rating. Early in the research phase, it became clear that success would rely on making it easy for assessors to pick up the tool and run with minimal training.

Diving deeper into Zero Net Carbon ratings

We partnered with industry experts to unpack the different modelling inputs that generate a Zero Net Carbon ‘pass’ or ‘fail’ rating. Then, we worked closely with assessors to understand their existing processes and map out the data input behind the rating. Through user testing with several prototypes, we translated our findings into a solution that imports industry-standard data, factors in modelling from Sustainability Victoria and CSIRO, and allows user input through an easy-to-use interface. The design simplifies what was a jargon-heavy, multi-platform process. We introduced approachable language, prioritised presentation of critical information and educational on-boarding content to support assessors through ZNC evaluations.

First steps toward more sustainable housing

In partnership, we designed a web tool that calculates the building’s energy usage, sustainability offsets and sizes its solar PV system to arrive at a Net Zero Carbon home accreditation. The tool will support volume home builders with developing more zero net carbon homes throughout Victoria. It brings Sustainability Victoria one step closer to broader uptake of the Zero Net Carbon standard. With opportunity to scale following the pilot program’s success, this tool could become key in ensuring Victoria meets its greenhouse gas emission targets in the residential sector.

Idea, opportunity or problem to solve?

Contact us


3/29 Cromwell St,
Collingwood VIC 3066
1300 368 277


55 Brisbane Street,
Surry Hills NSW 2010
1300 368 277