What does green really mean?


We have a problem in the construction industry.  It’s estimated construction and demolition waste make up to 50% of all landfill waste in New Zealand.  And the construction industry accounts for approximately 20% of our carbon emissions.  Yet we still have a shortage, particularly of affordable housing in Aotearoa.

We can’t stop building houses, but we have less than a decade to make significant reductions in our carbon emissions in order to limit global warming to an extent that the planet remains liveable for humans.  The time for talking, for conferences and webinars and, somewhat ironically, for writing articles, is long past. 

More than ever, we need architects to step up and show that we can build homes without damaging our ultimate home – the planet. 

And we need clients, developers, and the general public, as well as government legislation, on board.  But if you want to build a more sustainable home, where do you start?  There are so many different ‘green’ building standards and certifications, it can be difficult to get your head around them all – what does ‘green’ really mean?

Living Building Challenge

The Living Building Challenge is based on the philosophy of not only doing less harm, but rather aims to “create buildings that give more than they take”. It measures the real performance of a building over the first year of operation, across seven ‘petals’: Place, Water, Energy, Health and Happiness, Materials, Equity, and Beauty. The breadth of categories and measurement standards are more aspirational than other certifications, and this is generally considered to be the built environment’s most rigorous performance standard.  Unsurprisingly, there are only a handful of LBC certified projects in NZ.


Provided by the NZ Green Building Council (NZGBC), Homestar is one of the better known certifications for residential buildings. Houses can be awarded a Homestar rating from 6 star (above building code) to 10 star (world leading), based on points awarded across categories measuring energy use, insulation, ventilation, water use, materials, waste management and access to amenities.  The latest version also includes points for minimising embodied carbon emissions.


Homefit and Homefit Plus offer a considerably simpler assessment, specifically for existing homes.  They certify homes that meet sufficient criteria to be considered Warm, Dry and Safe.  If you are considering purchasing a home, they have a handy online tool to help you make a self-assessment.  Alternatively, you can go through the full certification process, for example if you wanted to market a rental property as Homefit or Homefit Plus.

Passive House

Passive House has a focus on the operational energy use of homes, and aims to minimise the energy required for heating and cooling primarily through well-insulated, airtight homes with mechanical ventilation.  One of the strengths of Passive House is the proprietary software used to model energy use.

Just as NZGBC have Homefit to accompany Homestar, Passive House also have the enerPHit certification for refurbishments of existing homes. These are just a few of the more common green certifications in NZ, and there are others for commercial buildings.  But whether you choose a specific system, or simply ask your architect to prioritise sustainability, collectively we need to aim higher, and start building homes that are better for people and better for the planet.


About Author

Phil MacKay

Phil Mackay is Business Devolpment Manger at Hamilton-based PAUA, Procuta Associates Urban + Architecture