A new report released by BRANZ, prepared by the Building Innovation Partnership, shows that currently available technologies could reduce operational greenhouse gas (GHG) emissions from New Zealand households by up to 89%. The research models how coordinated neighbourhood-level deployment of strategies such as heat pumps, rooftop solar PV, and electric vehicles can support the country’s net-zero targets.
The report, Pathways to Net-zero Residential Buildings and Urban Communities in New Zealand, evaluates five strategies known collectively as 'DEEDs': Decarbonisation of the electricity system, Electrification of heating and cooking, Energy efficiency upgrades, Digitalisation of energy systems, and Electrification of vehicles. These were assessed through a physics-based Urban Energy Model (UEM) simulating 60-household clusters across four climate-diverse regions: Auckland, Palmerston North, Christchurch and Dunedin.
The model incorporated variables such as home age, insulation level, heating systems, and energy use for transport and appliances. Key findings demonstrate that interventions like heat pump water heating, rooftop PV with batteries, and load-controlled EV charging can collectively achieve large emissions cuts without overloading local electricity networks.
Up to 25% reduction in electricity demand using hot water heat pumps, alongside significant drops in energy use and peak loads.
Electric vehicles provided the largest GHG emissions reduction across interventions, but increased electricity demand unless managed with load control.
Rooftop PV systems significantly cut GHG emissions and local grid consumption, though widespread adoption could introduce risks of high reverse power flows.
Wood-fuelled heating delivered modest emissions benefits and helped reduce peak electricity loads, particularly in colder climates.
The study concludes that three technological pathways—wood-fuelled heating with electrification, full electrification, and full electrification with distributed energy resources (PV and batteries)—can reduce household GHG emissions by 72–89%, depending on location. All scenarios rely on existing, market-ready technologies.
“These findings show that coordinated neighbourhood-scale adoption of proven technologies offers a technically feasible path to net-zero household emissions, without requiring expansion of the electricity network,” the authors state in the report.