NZ H1 Energy Efficiency — 2023 Requirements
New Zealand's Building Code Clause H1 sets minimum insulation requirements for new homes. The H1 5th edition significantly increased R-value requirements and became mandatory for all new building consents from 1 November 2023.
NZ Climate Zones
NZ is divided into 6 climate zones under NZS 4218:
| Zone | Cities/Regions |
|---|---|
| 1 | Northland, Far North |
| 2 | Auckland, Bay of Plenty, Gisborne, Hawke's Bay |
| 3 | Taranaki, Manawatū, Whanganui |
| 4 | Wellington, Nelson, Marlborough, West Coast |
| 5 | Canterbury, Otago, Invercargill |
| 6 | Central Otago, Queenstown, Southland inland |
Why H1 Changed in 2023
The updated requirements (particularly for Zones 5 and 6, where ceiling R-values jumped to R6.6) were driven by the government's goal of reducing household energy use and carbon emissions. Builders and insulators who haven't updated their standard specifications may be under-quoting.
Common Mistakes
- Using old R-values from pre-2023 H1 4th edition
- Confusing total R-value of the building element with the insulation batt R-value — they're different
- Forgetting slab perimeter insulation, which is now required in Zones 4–6
For the full H1 calculation method, use the BRANZ H1 tool. Always confirm requirements with your Building Consent Authority (BCA).