Net-zero Homes Hold the Key to New Zealand’s Carbon Neutral Goals

Climate change continues to be one of the greatest challenges facing Aotearoa and the rest of the world in the 21st Century. New Zealand has committed to meeting the Paris Climate Agreement’s goal of carbon neutrality by 2050, and that means fundamental changes, not just to the homes we build but also how we build them.

As we’ve written before, New Zealand has been slow to push for better-performing buildings, although companies like Craft Homes are making a difference one home at a time through innovative design, sustainable building practices, and public advocacy. Fortunately, more ambitious goals from the government, along with a wealth of new policy proposals, suggest change may be on the horizon!

• ​Read our summary of Proposed Party Policies for Sustainable Housing​

​The Ministry of Business Innovation & Employment (MBIE) has recently unveiled Building for Climate Change, a programme intended to reduce “emissions from buildings during their construction and operation, while also preparing buildings to withstand changes in the climate.”
 
This programme is very important because it recognises and addresses the role that construction practices and design principles play in the carbon emissions of New Zealand’s built environment. These policies target many of the largest barriers to more sustainable homes that New Zealand faces, and the construction industry will play a crucial role in their success. That’s where net-zero buildings enter the frame!

Passive solar new build home in Huia

What are net-zero buildings?
Net-Zero Energy buildings, or NZE buildings, are buildings that create more renewable energy than the total energy the building consumes.
 
The New Zealand Green Building Council, according to their Zero Carbon Road Map for Aotearoa’s Buildings, also accounts for carbon emitted during the construction process when defining net-zero buildings. In other words, it’s not just the energy lost to light bulbs and air conditioning that counts toward a home’s overall carbon emissions, but also the energy lost to construction and waste. Net-zero homes are eco-friendly long before you move in.
 
The operational emissions from running a home are far greater than the emissions from building the home in the first place, but it’s important to understand that effectively reducing operational emissions begins as early as the design stage.

• Read the NZGBC Zero Carbon Road Map for Aotearoa’s Buildings

For that reason, builders need to work with designers from the start to account for the way that homes are constructed. MBIE’s Building for Climate Change Programme has centred on two frameworks to do just that: The Whole-of-Life Embodied Carbon Emissions Framework and the Transforming Operational Efficiency Framework.

What is embodied carbon?
Embodied carbon refers to the carbon emissions of any material used in construction. This carbon footprint model considers the following:

• How far the material has travelled (energy spent on distribution)
• How the material was manufactured (energy spent on production)
• What can be done with the material at the end of its lifecycle (energy spent on disposal and replacement)

When we talk about embodied carbon, we’re considering more than just the energy efficiency of the home itself; we’re also considering the energy (and the carbon) that was spent to make that home a reality, as well as the energy that will be required when those materials reach the end of their life cycle. This allows us to contextualise the carbon footprint of our homes within the larger construction industry and helps us identify innovative ways to achieve carbon-neutral building practices—a priority of the Whole-of-Life Embodied Carbon Emissions Framework in the Building for Climate Change Programme.

What is operational carbon?
Operational carbon refers to the carbon emissions of the day-to-day operation of a home, from energy spent on lighting, heating, and ventilation to the gas burned at the stove or in the water heater. The Building for Climate Change Programme’s Transforming Operational Efficiency Framework focuses primarily on these areas.
 
The Healthy Homes Design Guide, which strives “to help designers and industry professionals bridge the gap between the current Building Code and the solutions required to achieve healthy, resilient, durable, comfortable, affordable, low carbon homes,” shines plenty of light on how important it is to build an energy efficient home. As you can see in the chart below, a home’s operational energy emits more carbon than building materials, home construction, water consumption, and end-of-life processes combined.

​Percentage of carbon emissions over the full life cycle of New Zealand residential homes (Source: The Healthy Homes Design Guide)

• Check out the Healthy Homes Design Guide

The Design Principles for Reducing Carbon Emissions
Clearly, operational emissions are more substantial than building emissions, so if you can create an energy-efficient home, you’ve gone a long way to reducing the carbon emissions of your new build home. Here are some of the crucial design elements that make a net-zero home possible:

• Using electricity, rather than gas, for heating and cooking
• Reducing the home’s embodied carbon
• Using timber-framed windows that meet Forest Stewardship Council (FSC) requirements
• Reducing construction waste
• Using more prefabricated build elements

How our Raglan build is helping put net-zero homes on the map in New Zealand
As we’ve written about recently, our off-grid new build in Te Mata near Raglan, which will be our personal home as well as a show home for passive homes in the area, will be an exciting demonstration of the comfort and savings a net-zero home can provide, as well as the effectiveness of net zero construction. Our new build will make use of the design principles mentioned above and will produce more renewable energy than we’ll use, making it a pristine example of the materials and building practices that we know will bring New Zealand closer to our goal of carbon-neutral housing by 2050.
 
Construction is freshly underway, and we can’t wait to share our progress with you!

• Read more about Toby and Cat’s net-zero home build near Raglan.

Make your new home a part of New Zealand’s carbon-neutral success story
NZGBC’s Carbon Roadmap for Aotearoa lays out a plan to ensure that all new homes built in New Zealand are net-zero carbon from 2030 and that every home in New Zealand is carbon-neutral by 2050. Here at Craft Homes, we’re doing our part to help New Zealand meet that goal. Get in touch today to learn more about the wide-ranging benefits of net-zero homes.