Thousands of homes to have carbon pollution levels slashed under revamped Homestar green home scheme

02 August 2021

Thousands of new New Zealand homes could be built to be much more climate-friendly, as Homestar, the green home certification scheme, relaunches today (Monday 2 August). 

Under the new version of Homestar, all homes aiming for a green home rating will now have to prove they have lower carbon pollution compared to an average new home.  

The average new house in New Zealand emits five times too much carbon pollution, and the newest version of Homestar has been created to play a key role in tackling this.  

The new version of Homestar is being described as “the most ambitious ever”, and comes after an extensive consultation involving hundreds of experts across Aotearoa.   

All Homestar rated homes will now be able to demonstrate how they’re using sustainable materials that don't pump out huge amounts of carbon pollution when created. This type of carbon pollution, which has been belched into the atmosphere during the production of building materials, is often called ‘embodied carbon’. Homestar will also include an embodied carbon calculator, helping builders to work out the levels of carbon emitted in the manufacture of the building materials. 

And all new Homestar homes must use energy efficient appliances for everyday things like heating, hot water and lighting, meaning that both carbon emissions and household bills should be reduced. Carbon emissions created through using energy to power and run a home are referred to as ‘operational carbon.’ 

Rated on a scale from 6 to 10, a 6 Homestar home will reduce carbon through mandatory energy and operational carbon targets, unlike homes built to the current Building Code. A 10 Homestar home will have to show predicted energy consumption and carbon emissions significantly lower than an average New Zealand home. 

Leading international agencies, including the International Energy Agency and the OECD  have criticised New Zealand’s Building Code – the minimum legal standards to which buildings have to be constructed. 

Andrew Eagles, chief executive of the Green Building Council, said: “Making New Zealand homes better will help us tackle climate change, and give families healthier, warmer, and drier homes. 

“Far too many Kiwi homes are cold, damp, and unhealthy, pump out far too much carbon pollution in their construction and in the energy they use, and far too often saddle Kiwi families with high household power bills. 

“That’s why we’ve launched the new update of Homestar – the most ambitious ever version. We’re hoping that Homestar will provide healthy, cosy homes for thousands and thousands of families, and play a much needed role in slashing climate change pollution.” 

Almost 5,000 new homes were registered and certified under Homestar in the last year. 

Besides cutting carbon pollution, the revamped Homestar gives increased importance to a number of other key areas. 

These include making it easier to keep a home warm in winter and cooler in summer, well ventilated with fresh air, and dry, keep household bills lower through energy and water efficiency, building with healthy, sustainable materials, and reducing the amount of waste getting dumped in landfill. Each of these areas must now hit a particular level to achieve a Homestar rating. 

The Green Building Council, the not-for-profit organisation behind Homestar, hope that this will give homeowners confidence that all Homestar homes rated under the improved scheme will be cosier, drier, healthier places than homes built to minimum Building Code levels. 

The government is working to reduce the carbon emissions from homes and buildings, which are responsible for 20% of climate changing pollution in New Zealand. The new version of Homestar will align with this project, called the Building for Climate Change programme. This will allow builders using Homestar to develop the skills and knowledge needed for upcoming changes to the Building Code.