Green Star Buildings is the Green Building Council of Australia’s (GBCA) sustainability rating tool for the design and construction of new buildings and major refurbishments. The tool provides a comprehensive framework for delivering healthy, resilient and positive buildings with reduced environmental impacts and improved outcomes for occupants and communities.

Green Star Buildings v1.1 is a revision to Green Star Buildings v1. The update strengthens alignment with GBCA’s strategic focus areas of climate action, nature and circularity, while also incorporating industry feedback and technical clarifications.

Green Star Buildings v1.1 opened for registrations on 21 October 2025 and became mandatory for all new project registrations from 1 May 2026.

The Green Star rating is determined by comparing the number of points achieved out of a possible 100 points, with defined thresholds for star ratings:

Projects must also meet all mandatory Minimum Expectations to achieve certification.

One Click LCA can be used to support compliance and point achievement under several Green Star Buildings credits, particularly those for Upfront Carbon Emissions and Impacts Disclosure credits.

Upfront Carbon Reduction credit

This credit focuses on reducing upfront embodied carbon emissions from materials and construction processes. Projects can earn up to 6 points by demonstrating reductions in upfront carbon emissions (A1-A5) compared to either a benchmark building or a reference building, depending on the selected compliance pathway.

Projects can comply through either:

As per the Upfront Carbon Emissions calculation guide, “a Reference Project is a hypothetical project of the same size, shape, location, floor area and glazing areas as the Proposed Project. The aim of the Reference Project is to provide a point of comparison for reductions against, by developing a building that could have been built in place of the Proposed Project provided no work was done to reduce its upfront carbon emissions.”

Points are awarded based on achieving progressively higher reductions in upfront carbon emissions.

Impacts Disclosure credit

Previously, Green Star Buildings v1 included the Life Cycle Impacts credit, which rewarded reductions in whole-of-life environmental impacts through a whole building Life Cycle Assessment (LCA). In Green Star Buildings v1.1, this has evolved into the Impacts Disclosure credit, reflecting a broader focus on transparency and environmental impact disclosure.

Projects can achieve 1 point under this credit through the disclosure and assessment of life cycle impact data using recognised LCA methodologies and Environmental Product Declarations (EPDs).

This requires a whole-of-building, whole-of-life (cradle-to-grave) LCA using EN 15978, with reporting across all life cycle modules (A–D) and disclosure of multiple environmental indicators in accordance with EN 15804+A2.

The same whole building Life Cycle Assessment (LCA) can be used to support both the Upfront Carbon Reduction and Impacts Disclosure credits, provided the specific requirements for each credit are addressed. The Upfront Carbon Reduction credit assesses upfront embodied carbon emissions across modules A1–A5, while the Impacts Disclosure credit requires a whole-of-building, whole-of-life assessment covering modules A–D in accordance with EN 15978.

At minimum, the LCA must include all major building elements within the project scope, including:

The assessment must capture at least 90% of physical materials and at least 90% of the financial value of building products included within the project scope. Additional materials that contribute significantly to upfront carbon emissions must also be included.

Project teams may choose to conduct LCAs as per:

One Click LCA supports both standards. Use the appropriate tool based on the standard to report on

Create a building project and select the relevant Green Star tool (see Data Scope) as the chosen calculation tool, and create a new design.
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Fill in the building materials query of the design either manually or by import. Add all of the materials required by the calculation scope (see above). This information will be used to calculate the raw material harvesting, transportation and manufacturing impacts in A1-A3.

​Check the material service life. This information will be used to calculate the material replacements for B4-B5. Material service life means how long each material will last in your building. If the service life is less than 60 years, the material will have to be replaced. From an environmental impact point of view, this means additional emissions from the production of new material that is needed to replace the old one.

Each of the materials in the One Click LCA database has a default service life. However, as the exposure conditions of the materials may vary, it may be good to check that the service life matches the condition of your building. It is especially important to check the external wall and roof material service lives, as the weather conditions may vary greatly between areas.

Adjust the localization of each material as needed (Expert feature). This information will be used to compensate for any material data chosen from another area to match your project’s local material manufacturing conditions.
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Once the correct materials and quantities are provided, set the transportation distances from the material manufacturer to the project site and the transport methods. The default transportation distances can be set up from the project’s LCA parameters page. If they are chosen, any material will use the average distance unless a more specific one is given in the query. This information will be used to calculate the impacts of material transportation in A4.

Fill in the building area query. This information will be used as a divider for the results in a separate result row, and it will help you to understand how the results compare to other projects. Gross floor area is required.
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Set your calculation period to 60 years as the requirement for this certification.

After you have done one LCA calculation, you can now view the results.

You create as many additional designs as you wish, either by copying the first one or by creating a new empty one. This can be used for creating a reference building to then make reductions against. To copy a design, click its name and choose 'Copy'. To create a new one, press the '+ Add a design' button on the project main page.
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Once you have a proposed and a reference building, you can go to the results page of the proposed building, click 'Compare Designs', then choose to compare with your reference building. This will then allow you to see the percentage reductions you've been able to make in your results table. Results can be seen for each life-cycle stage, and results per square metre are available at the bottom of your results table.