H1 Changes & H1 Calculations

The new NZBC H1 requirements come in to effect for consents submitted on or after 1st May. These changes are significant for insulation. There are now six climate zones, and three different Construction R-Value requirements for suspended floors.


Compliance Pathways

Schedule Method

Meet the minimum Construction R-Values listed in Table of H1/AS1, where;

  • The glazing area is 30% of less of the total wall area; and
  • The combined glazing area on the east
  • south
  • and west facing walls is 30% or less of the combined total area of thee walls; and
  • The skylight area is no more than 1.5m2 or 1.5% of the total roof area (whichever is greater);
  • The opaque door area is no more than 6m2 or 6% of the total wall area (whichever is greater)

NZBC H1/AS1 Energy Efficiency for all housing and buildings up to 300m2

Calculation Method

Compares the ‘proposed’ building with the ‘reference’ building which is insulated in accordance with the Schedule Method. This permits the roof, wall, floor, window, door and skylight insulation combinations to differ from the Schedule Method tables, but the building must perform at least as well as the reference building.

Can only be used where the glazing area is 40% of less of the total wall area.

Fairly simple calculation that Premier Insulation can offer to support your consent appliaction.

Modelling Method (H1/VM1)

Verification of the design is achieved by demonstrating that the energy use of the proposed building design does not exceed the energy use of the reference building using computer modelling.

Highly detailed calculations that require certified software.
Outsourced service; www.H1Solutions.co.nz

Technical Support Material

  • H1/AS1 (Fifth Edition)
  • H1/VM1 (for Modelling Method compliance)
  • BRANZ House Insulation Guide (new version due to market soon)
  • BRANZ Bulletins;
    • 660 High Performance Walls
    • 661 High Performance Roofs
    • 668 H1 Revised
    • 670 Specifying windows & doors under H1
    • 672 Specifying Floors
    • Oculus Architectural Engineering website
    • NZGBC.h1calculator.org.nz
    • H1solutions.co.nz
    • PHINZ High-Performance Construction Details Handbook

Get in touch for a free H1 calculation for your build.

Building design will very likely need to change to meet the new standards. How much will depend on the site requirements and building design. Our team will guide you through the process.

CALL 09 262 0921