As the new year rings in changes, requirements for Green Star certification are also shifting. New ratings come into effect from 1 May this year, meaning building projects must demonstrate new, higher upfront carbon reductions, as well as achieve additional requirements.
For example, projects currently seeking a 4 Star rating must have at least a 10% reduction in carbon. But after 1 May 2026, this figure increases to 15%. Similar staged reductions in operational energy use have also been mandated.
The Credit Achievement of the Other Carbon Emissions credit is related to refrigerants. Limiting these emissions is currently only mandatory for 6 Star projects, but will include 5 Star projects from May this year. The Exceptional Performance threshold for this credit involves purchasing offsets for any emissions that have not been eliminated.
Grid Resilience is the final credit impacted by this step change. This relates to reducing electricity consumption when overall demand is at its highest. This is a key aspect of decarbonising the grid as it reduces the need for new power-generation infrastructure.
The New Zealand Green Building Council engaged engineering consultancy Beca to assist in setting decarbonisation trajectories for upfront embodied and operational carbon.
Launched in 2024, the Green Star Buildings Carbon Reduction Strategy contains comprehensive and credible targets for the building industry.
More robust than international standards, the revised percentages have been calculated according to a carbon budget that’s in line with the Paris Agreement.
The amount of carbon we can continue to emit into the atmosphere is finite – and every kilogram accounts for keeping warming below the commonly agreed 1.5 °C.
This budget can be divided between countries and industries, and a share attributed to individual buildings. But over time, the residual budget falls, so new buildings become subject to increasingly stringent targets.
“Every emission-related activity reduces what’s left in that budget,” says Joe Quad, NZGBC’s Technical Development Lead, who helped develop the Green Star Buildings Carbon Reduction Strategy with Beca.
“Our calculations are based on how many buildings are projected to be built and the emissions they’re each allowed. In reality, every single building should meet the budget because every building draws down from that budget,” he says.
According to MBIE, the built environment contributes around 15% of Aotearoa’s carbon emissions. Reducing emissions from buildings is essential to Aotearoa meeting its climate goals.
The NZGBC’s strategy is a proactive step in accelerating this transition to a low-carbonfuture.
“Transitioning to a low-carbon future means more than setting a single target and working towards it,” says Sam Archer, NZGBC director of Market Transformation. “Green Star is about transforming the way our built environment is designed, constructed and operated.
It’s essential that these tools and certifications are updated to reflect reality – that means in both the global environment and local building and construction sector.”
To secure the existing thresholds, project submissions must be made before 1 May 2026, with the end of May signalling the deadline to finalise registration. Projects registered after 1 May must meet the new targets.
For more about how the strategy’s targets were established, download the Green Star Net Zero Ready Buildings report.
To find out more about embodied carbon, including NZGBC guides, methodologies, databases, calculators and more, visit our website's embodied carbon page.