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Changes to Building Code clause H1 bring the biggest energy efficiency improvements in over a decade, and at Comfortech®, we’re well prepared to help you with these changes.

Research shows that damp, mouldy, poorly ventilated homes affect the respiratory health of many New Zealanders. To help address these issues, from 01 May 2023, MBIE has introduced the new 5th edition of H1/AS1 and H1/VM1 for housing and H1/AS2 or H1/VM2 for buildings greater than 300 m².   

The changes focus on significant increases to insulation requirements and the introduction of six new climate zones to reflect the specific weather experienced in different parts of the country will help New Zealand homes and buildings to become warmer, drier, and more comfortable.

H1 will also help to reduce the energy needed to heat homes by up to 40 per cent, as well as a 23% reduction on average across large new builds, leading to positive health impacts and increased energy savings for New Zealanders.

At Comfortech®, we've got your H1 needs covered. Here's how we're helping you to navigate the changes: 

  • Single layer and double layer Pink® Superbatts® insulation solutions
  • H1 thermal calculation and modelling service
  • PinkFit® insulation installation network, ensuring correct product installation 

For more information on these and other upcoming changes to the Building Code, please visit the 2021 Building Code Update section of the MBIE website.




Energy Efficiency for small buildings under 300 m²

These new R-values will result in a reduction of the energy needed for heating residential homes of approximately 40% compared to previous minimum status quo requirements.


Energy Efficiency for large buildings over 300 m²

Construction R-values for buildings greater than 300 m². These new requirements will be implemented with a 1 year transition period. This aims to reduce the energy needed for heating and cooling by 23% on average across new large buildings, compared to previous minimum status quo requirements.

There is no one-size-fits-all solution for the new H1 building code changes. You choose the method to calculate compliance and the products to use.

There are three methods for Building Code compliance:

  • The Schedule method is the simplest – you meet or exceed the minimum construction R-values in H1 for the ceilings, walls, windows and floors. The limitation on this compliance pathway is that you cannot exceed 30% glazing.
  • Calculation and Modelling methods give more flexibility including a larger percentage of glazing than the schedule method. The ceiling thermal performance can be balanced against the windows, walls and floor performance to allow for different solutions. The calculation and modelling methods also take into consideration energy usage in a more holistic manner.

Walls and ceilings

Ceiling construction R-values have increased significantly from R2.9 or R3.2 to R6.6 across all six new climate zones. Specifiers have choices:

  • Simply meet the new R-values via the Schedule method – we have developed single- and double-layer solutions for this.
  • Use a Calculation or Modelling approach – you could use a single layer solution of a lower construction R-value (at least R3.3) for the ceilings and increase thermal performance in other areas of the building such as walls and windows. Comfortech® recommends Design Navigator or the BRANZ House Insulation Guide as simple tool to calculate the H1 performance via the Calculation Method. For modelling Method calculations, tools like Speckel are also useful.

Walls have changed little, but we expect a move to R2.6 or R2.8 wall batts to offset the high thermal bridging highlighted in a 2020 BRANZ Beacon Pathway report. This study found new timber-framed walls have on average 34% framing (and up to 55%), well above the 12 to 18% assumed in the Building Code.


Have questions about insulation?