Green Star FAQs


FAQ F-00517
What emission factors are to be used for the reference building in the Upfront Carbon Reduction credit?

Projects targeting Upfront Carbon Reduction - Pathway B: Reference building pathway in Green Star Buildings v1.1 are to use a 20% increase on the average emission factors in the NABERS National material emission factors database when calculating the upfront carbon of the reference building.

For example: The average emission factor for concrete in-situ - 40MPa is 305kgCO2e/m3. A 20% increase would be (305kgCO2e/m3 x 1.20) = 366kgCO2e/m3. 366kgCO2e/m3 is to be used for 40MPa concrete in the reference building.

The upfront carbon of the proposed building is to use the NABERS default emission factors when product-specific emission factors are not available.

This will be included in the Upfront Carbon Reduction - Pathway B: Reference building pathway calculator, and in the updated Upfront Carbon calculation guide due for publication in early 2026.

Please note there are changes to the way biogenic carbon and Climate Active certified products are treated in Green Star Buildings v1.1 to align with NABERS rules. Refer to the Submission Guidelines for further information. 





Rating Tools

This FAQ is related to the following Rating Tools, Categories or Credits:

  • Green Star Buildings v1.1 / Positive / 24 Upfront Carbon Reduction


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