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New energy efficiency requirements for new builds

JULY 1, 2022










The latest changes to the Building Code will see some of the biggest shifts in requirements in over a decade.

High time for change as NZ’s current requirements, particularly in insulation are well below similar temperature countries across the western world. Changes for all parts of the sector are going to be ushered in with the goal of moving towards better quality homes and buildings for New Zealanders with a reduced environmental impact.

More specifically the changes will see buildings made warmer, drier, healthier and more energy efficient reducing the energy needed to heat homes by up to 40%.

How will this be achieved?

H1/AS1 will include, but is not limited to, the following major changes:

  • Lifting minimum levels of insulation to make homes more comfortable and easier to heat and cool
  • Introduction of a new climate zone map to acknowledge variations in climate around NZ
  • Limit scope of current document to housing and small buildings










Summary of Changes

1. New Climate Zones

The zone map shows MBIE is increasing the number of climate zones used to define insulation requirements from the previous 3 to 6. This change better accounts for the different temperatures experienced across the country.

Homes will need to be designed and built with specific minimum insulation requirements for the climate they’re located in making them more suited to where they are being built. The new climate zones follow territorial authority (local government) boundaries.

MBIE developed the new R-values with the following intent in mind:

  • Future proofing: By increasing baseline performance of buildings the aim is to put NZ in better position to meet future carbon emission caps.
  • Practical plan for transition: Current design & construction practices in NZ are still able to be used with the new R-values. This allows the achievement of quicker transition times with less impact on existing supply chains.

To demonstrate compliance to the new standards when using H1/AS1, the roof, windows, external walls and floor of a new home or small building need to meet or exceed each of the minimum R-values for the relevant climate zone. Concessions will be considered provided the overall thermal performance of proposed new home or small building is equal or better.

Transition period

The transition period for the new Fifth edition of Acceptable Solution H1/AS1 and Verification Method H1/VM1, effective November 2021, will be one year. The existing Acceptable Solution H1/AS1 and Verification Method H1/ VM1 4th Ed. documents will remain in force until 2 November 2022.

What else in on the horizon?

The next phase of Building for Climate Change programme is planning on introducing caps on carbon emissions and operational efficiency of buildings requiring a more comprehensive consideration of building design, construction methods and materials.

With the changes confirmed and the road map into the future clearer, Mitre 10 is working closely with manufacturers and suppliers to ensure that we can bring you a range of acceptable solutions to suit your residential building needs under the new regulations.

Please note that as of June 2022, MBIE is currently consulting on a proposal to extend the transition period for Acceptable Solution H1/AS1 5th Ed for housing. Changes have not yet been confirmed. For more information on the upcoming changes or any of the information above please consult the MBIE website.

2. New R-Values

MBIE is proceeding with changes to roof, window, wall, and underfloor insulation with the new minimum values summarised in Table 1.3. ‘Construction’ R-values are the total for the whole roof or wall or floor, not a material R-value.

The biggest impact will be in the application of roof insulation where there will be a doubling of the required construction R value across all climate zones.









Click here to download a copy of Acceptable Solution - H1/AS1 - Energy Efficiency (effective 29 November 2021) | 5th edition (