The numbers.
H1 splits NZ into six climate zones. The new minimum R-values (Schedule Method) versus pre-2022:
- Walls — was R1.9 nationwide. Now R2.0 in Zones 1–2, climbing to R2.0–R2.4 by zone.
- Roof — was R2.9–R3.3. Now R6.6 across Zones 1–5, R7.0 in Zone 6 (Central Otago and the Southern Lakes).
- Floors — was R1.3–R1.5. Now R3.0 nationwide.
- Glazing — was R0.26. Now R0.37–R0.50 by zone, effectively requiring double glazing in thermally-broken aluminium or better.
Where it bites.
Three areas where the new numbers force real change:
- Roof depth. R6.6 needs ~270mm of glasswool or ~190mm of high-density wool, plus a service cavity. Old 90mm bottom-chord trusses are gone.
- Floor strategy. R3.0 under a timber floor means insulating between the joists and adding a sub-floor blanket. For concrete slabs, perimeter and underslab insulation is now standard.
- Glazing. Single-glazed windows are non-compliant in any climate zone. Thermally-broken aluminium or uPVC frames with low-E double glazing are the new floor.
The cost reality.
For a 220 m² standard residential build:
- Roof — additional $4k–$6k in materials and labour.
- Floor — $3k–$5k for a typical concrete slab, $4k–$8k for timber floor.
- Glazing — the big one. $15k–$25k uplift over single-glazed for a typical opening schedule.
- Walls — usually achievable with R2.4 batt within existing 90mm framing, $1k–$2k uplift.
"Total uplift sits at $25k–$40k for a typical new build — but the long-term operational savings (and resale comparability) make it the only sensible spec now."
Calculation methods — pick the right one.
- Schedule Method — simplest. Meets minimum R-value for each element. Used when the design fits within the schedule constraints (glazing area limits, etc.).
- Calculation Method — trade off one element against another (e.g., higher-R walls to allow more glazing).
- Modelling Method — full thermal performance modelling. Highest flexibility, highest assessor cost.
Practical takeaway
For most residential briefs the Schedule Method is enough — and our advice is to design to it from day one rather than try to claw back compliance via modelling later. The 2022 numbers are now the cost-base of every NZ new build. Pretending they're optional won't help your budget.