H1 Building Code Changes

The Design Windows range meets all the requirements of the Building Code H1 energy efficiency standards.

The H1 Clause of the Building code is in place to regulate energy efficiency of our buildings in New Zealand. Specific to walls, floor and roof insulation as well as thermal performance of windows and doors.
Changes to the H1 clause were published in November 2021 and implemented over a range of time periods with all requirements being effective as of 2nd November 2023.

Key dates

All window and door construction in new housing now has a 2-step increase. The first step is a minimum construction R-value of R0.37 for the whole country from 3 November 2022. After that, the date of the second step varies by climate zone:

  • From 1 May 2023, the minimum R-value in:
    • climate zones 3 and 4 rises to R0.46
    • climate zones 5 and 6 rises to R0.50
  • From 2 November 2023, the minimum R-value for
    • climate zones 1 and 2 rises to R0.46

To learn more about H1 requirements, building.co.nz has some great resources including training modules.

For more information on how Design Windows suppliers are complying with the new requirements visit:

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One of our qualified team will work with you to work out the perfect fit of product to project