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Energy efficiency

Energy efficiency is about using the least possible energy to perform a task. Reducing energy loss and using passive design elements such as effective house orientation, glazing and insulation can make homes warmer, healthier and cheaper to run.

Energy efficiency is at the heart of sustainable building. Passive design and reducing energy loss can help lessen environmental impact and is key to progressing towards a net-zero carbon economy.

See Environment and zero-carbon research for the work BRANZ does in this area.

Resources for designers and builders

Findings from BRANZ energy efficiency research contributes to useful online resources, calculation tools, books, bulletins and seminars as well as standards and government policy. Topics include passive solar design, insulation, thermal bridging, glazing, space and water heating, and preventing heat loss.

  • Level: The authority on sustainable building

    Level will help you design and build homes that have less impact on the environment, are healthier and more comfortable and have lower running costs.

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  • H1 Energy efficiency support

    Building Code clause H1 Energy efficiency (4th edition) came into force on 1 January 2017. This page contains useful information and tools to aid in applying the H1 requirements.

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  • BRANZ House insulation guide (5th edition)

    This guide helps designers assess the thermal performance that can be expected for given levels of insulation and common construction options.

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  • NZS 4218:2009 calculation method tool

    Select the climate zone and wall construction type(s) and enter area and construction R-values for the various building elements. The tool applies the calculation method automatically, and pass/fail compliance is determined.

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  • ALF (Annual Loss Factor) 4.0: Thermal modelling tool

    ALF (Annual Loss Factor) is a tool for determining the building performance index (BPI) of a house design. It can be used to show compliance with New Zealand Building Code clause H1 Energy efficiency.

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  • Thermal bridging calculation tool

    This tool determines the thermal performance of cavity insulated timber-framed walls. It may also be used to determine the steady state R-value (U-value) and compare results.

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  • eLearning modules: H1 Energy efficiency

    These modules cover R-values and modelling methods to demonstrate compliance with Building Code clause H1 Energy efficiency.

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Services for manufacturers and distributors

Energy efficiency is assessed as part of BRANZ product testing. We can test the thermal efficiency of many building materials and elements, including thermal insulation.

  • Appraisals

    A BRANZ Appraisal is a robust, in-depth and independent evaluation of a building product or system to assess whether it is fit for purpose and meets Building Code performance requirements.

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  • CodeMark

    CodeMark is a voluntary product certification scheme that provides an easily understood and robust way to show a building product, design or method meets the requirements of the New Zealand Building Code or the Building Code of Australia.

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