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Note: National Embodied Carbon Data Repository is now live 📢

New Zealand’s National Embodied Carbon Data Repository, NECO2, is now freely and publicly available. View detail here.

Up-Spec: Specifying higher-performing homes

Up-Spec provides data on practical and cost-effective measures to improve the performance of new homes. Specific data is provided across nine New Zealand climate zones, focusing on comfortable temperatures, energy efficiency and water management. The pages here were originally developed when H1/AS1 and H1/VM1 4th edition were the applicable compliance documents for Building Code clause H1 Energy efficiency.

  • Climate zones

    Figures are available for simple performance upgrades in nine regional climate zones: Auckland, Hamilton, Tauranga, Napier, Wellington, Nelson, Christchurch, Dunedin and Invercargill.

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  • Comfortable temperatures

    Up-Spec focuses on the most practical thermal efficiency opportunities for stand-alone volume-built homes, which will improve their year-round comfort and reduce additional heating and cooling needs.

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  • Energy efficiency

    Energy efficiency improvements explored in Up-Spec include options for installing photovoltaics for solar energy generation, correct sizing of heat pumps for space heating and energy-efficient appliances and lighting.

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  • Water management

    Improvements explored to reduce water use include water-efficient appliances and tapware, greywater recycling and rainwater tanks.

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Up-Spec tools

BRANZ has developed calculation tools to help with designing and specifying higher-performing homes.

Related resources

These BRANZ resources relate to improving the performance of New Zealand houses.

Updated: 5 September 2025