Overview
Green Star Buildings NZ is the latest iteration of New Zealand’s rating system for sustainable commercial buildings (new builds and major retrofits), replacing the older Green Star Design & As Built NZ v1.1 rating system. Projects registered under the previous Design & As Built tool closed on 30 May 2025, with submissions now moving exclusively to Green Star Buildings NZ.
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:
4 Star – Represents Best Practice: requires a minimum of 15 points
5 Star – Denotes New Zealand Excellence: requires a minimum of 35 points
6 Star – Signifies World Leadership: requires a minimum of 70 points
One Click LCA can be used to achieve points under two key credits (Upfront Carbon Emissions and Life Cycle Impacts credits) that contribute significantly to Green Star Buildings NZ certification.
Upfront Carbon Emissions credit
This credit focuses on reducing the upfront carbon emissions from materials and products used in the building. Projects can earn up to 8 points by demonstrating reductions in upfront embodied carbon compared to a reference building.
A Minimum Expectation of at least 10% reduction is required for eligibility.
Points are awarded based on the extent of reduction, starting at 15% for 1 point and reaching 53% for 8 points. Projects targeting 5 or more points must also comply with the Net Zero Ready Pathway, which includes specific fossil fuel and refrigerant requirements.
Points | Reduction Requirement (vs. Reference Building) | Conditions |
Minimum Expectation | ≥ 10% reduction in upfront carbon emissions | Required for eligibility |
Credit Achievement | Net Zero Ready Pathway | Required from 5 points onward |
1 point | ≥ 15% reduction in upfront carbon emissions |
|
2 points | ≥ 20% reduction in upfront carbon emissions |
|
3 points | ≥ 26% reduction in upfront carbon emissions |
|
4 points | ≥ 31% reduction in upfront carbon emissions |
|
5 points | ≥ 38% reduction in upfront carbon emissions | Must meet Credit Achievement |
6 points | ≥ 45% reduction in upfront carbon emissions | Must meet Credit Achievement |
7 points | ≥ 50% reduction in upfront carbon emissions | Must meet Credit Achievement |
8 points | ≥ 53% reduction in upfront carbon emissions | Must meet Credit Achievement |
Life Cycle Impacts credit
This credit rewards reductions in environmental impacts across the building’s full life cycle. Projects can earn up to 2 points by demonstrating impact reductions compared to a reference building, based on a whole-of-building, whole-of-life (cradle to grave) Life Cycle Assessment (LCA), in accordance with EN 15978.
Key requirements include:
Results must be reported per square metre of Gross Floor Area (GFA).
The Credit Achievement cannot be claimed if the calculated impact in any single category (after normalisation and weighting) is worse than -10%.
A maximum of 10% reduction can be achieved through Module B6 (operational energy use).
Points | Reduction Requirement (vs. Standard Practice) |
1 point (Credit Achievement) | ≥ 15% reduction in overall life cycle impacts |
1 additional point (Exceptional Performance) | ≥ 30% reduction in overall life cycle impacts |
Life-Cycle & Results Scope
The Upfront Carbon Emissions credit focuses on Life Cycle Stages A1–A5 (product and construction stages), while the Life Cycle Impacts credit requires a comprehensive cradle-to-grave assessment, covering Life Cycle Stages A–D as defined by EN 15978.
Assessment Scope
The building elements included must meet the following scope criteria:
Be part of the warm shell – Includes all substructure, superstructure, and envelope components delivered as part of a complete tenancy-ready space (e.g. ceilings, floor coverings, lighting, HVAC services above the ceiling, risers).
Be permanent – Covers structural and non-structural elements that are intended to remain for the building’s lifespan (excludes temporary site works and non-permanent tenant fit-outs).
Fall inside the dripline – Includes all components within the building’s footprint, excluding external features like awnings, canopies, and site-wide hardscaping.
Include ancillary buildings and systems only if they contribute to core warm shell services (e.g. external HVAC units, water tanks).
In addition to core elements, the following must also be reported but declared separately:
External works – e.g. carparks, driveways, hardstands, retaining walls, and landscaping not directly supporting the warm shell.
All permanently installed building elements up until the point the building is occupied by the first tenant. – e.g. partition walls and kitchenettes.
Fittings and furniture – reported only where permanent and not part of a loose fit-out.
Where inclusion is unclear, elements should be treated conservatively by including them in the LCA and justifying exclusions where necessary.
Data Scope
Project teams may choose to follow either:
EN 15978:2011 (CEN, 2011) and EN 15804+A1:2013 (CEN, 2013)
prEN 15978-1:2021 (CEN, 2021a) and EN 15804+A2:2019/AC:2021 (CEN, 2021b)
One Click LCA supports both approaches. Use the appropriate tool based on the standard selected:
LCA for Green Star (AUS/NZ) - compatible with EN 15804 +A1 datasets
LCA for Green Star New Zealand (EN15804+A2) - compatible with EN 15804 +A2 datasets
The BRANZ CO₂NSTRUCT database (GWP-only) is not available in the Green Star tools. However, it can be accessed via the Global Carbon tool and used as an interim option if this data is required. To address this, our Product Team is developing a new carbon tool aligned with the NZGBC Embodied Carbon Methodology.
Guidance
Create a project
Start by creating a building project and selecting the appropriate tool based on the standard followed (see Data Scope ). Then, create a new design (ideally for the proposed building) to begin your assessment.
Building Materials
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 Life Cycle and Results Scope). 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 50 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.
Transport
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.
Building Area
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.
Calculation Period
Set your calculation period to 50 years as the requirement for this certification.
If you are following older guidelines (e.g. Green Star Design & As Built NZ v1), this may be set to 60.
Next steps
After you have done one LCA calculation, you can 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.
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.