H1 6th edition: what changed, and what it means on site

What H1 is — in plain English

H1 is the energy-efficiency clause of the New Zealand Building Code. For a builder it mostly means one thing: the construction R-values — how much insulation the roof, walls, floor and windows have to deliver — and those targets change by climate zone (New Zealand is split into six). The Acceptable Solution H1/AS1 is the recipe most residential work follows to comply.

What changed in the 6th edition

The H1/AS1 6th edition took effect on 27 November 2025. The headline change for builders is that the Schedule Method has been removed — the simple “just use these R-values” table is gone, and compliance now runs through the Calculation Method (or full thermal modelling). In practice that means more attention to thermal bridging — the heat lost through the timber framing itself — so the wall build-up has to be worked out, not just looked up.

A transition period applies, so the previous (5th) edition can still be used for some consents already under way — always confirm the current transition date for your consent on building.govt.nz.

What it means on site

• More insulation in the roof, walls and floor than older builds — and it has to be installed to actually achieve the rated R-value, not just stuffed in.
• Framing and thermal bridging matter: closer stud spacing and more timber pull the wall's real R-value down, so the build-up has to be designed to hit the target.
• Glazing has to pull its weight — double glazing and better frames in most zones.

This is a plain-English summary for builders, not the standard itself — check the current H1/AS1 on building.govt.nz for the controlling detail. See the full feature guide or how Toolie quotes a job.