NZ building-standard energy levers — high-performance & passive house (compiled synthesis)
Compiled research — upstream-referenced; baseline is post-2023 H1 code
A Perplexity Deep Research synthesis. The “1.0” baseline is a post-2023 H1 code COMFORT new build (~50 kWh/m²/yr modelled to-temperature), NOT existing-stock actual demand. PH multiplier is HIGH confidence; capex premiums MEDIUM (BRANZ SR385 2018 data inflation-adjusted; Basham single-builder). Apply the multipliers as RATIOS — see NI relevance.
Summary
The D17 building-standard lever values for the NI model: space-heat-demand multipliers and per-dwelling capex premiums for two efficiency tiers above the post-2023 H1 code baseline. A high-performance build (Homestar 7–8 / Superhome Base+) roughly halves space-heat demand (multiplier ~0.50) for a ~35,000/dwelling premium; a PHI-certified Passive House cuts it ~88–92% (multiplier ~0.12) for ~60,000/dwelling. Sourced from BRANZ SR385/SR483, PHINZ, Jason Quinn’s Passive House for NZ (2019), Basham Building, and NZGBC. Fills RT_185 (④c building_standards); feeds D04. (The H1 code baseline these multipliers sit above is now primary-sourced as OT_043 — H1 5th ed: roof R6.6 / wall R2.0 / floor R2.5–3.0 / window R0.46, ~40% less heating than the prior code.) (The Homestar capex figures behind the high-performance premium now have their BRANZ primary ingested — OT_085 (SR385): e-Cubed 2018 8-Homestar ~21k–34k + Ade 2018 Table 1 v4 8★ $47,372 (2018 NZD); SR385 reports these from Ade 2018 / e-Cubed 2018. Note SR385 is Homestar-based — it supports the high-performance tier, not the Passive House premium.)
Key claims
- claim: "The post-2023 H1 code baseline space-heating demand is ~50 kWh/m²/yr (national central; ~25–35 in Auckland zones 1–2, ~55–75 in cold zones 3–6); the 2021–2023 H1 upgrade targeted ~40% heating-energy reduction vs the pre-2021 code. Reference dwelling: 150 m², ~NZD $525,000 ($3,500/m²) build cost."
source_location: "§1 Baseline Definition / §5.1 Assumptions"
- claim: "A high-performance build (Homestar 7–8 / Superhome Base+) achieves ~20–35 kWh/m²/yr space heating → a multiplier of 0.40–0.70 (central 0.50) vs the H1-2023 baseline — roughly half the space-heat energy of a standard code-compliant new build."
source_location: "§2.2 / §4.1 Consolidated Comparison"
- claim: "High-performance capex premium is ~NZD $20,000–$55,000 per dwelling (central ~$35,000; ~4–11% uplift on a $525k build), from BRANZ SR385 Homestar cost data (2018) inflation-adjusted ~30% to 2024."
source_location: "§2.3 / §4.2 CAPEX Premium Summary"
- claim: "A PHI-certified Passive House meets ≤15 kWh/m²/yr space-heat demand (NZ certified case studies 7–22 kWh/m²/yr) → a multiplier of 0.08–0.20 (central 0.12), i.e. ~88–92% less space heating than a post-2023 H1 code build (PHINZ states 90%)."
source_location: "§3.2 / §4.1"
- claim: "Passive House capex premium is ~NZD $45,000–$90,000 per dwelling (central ~$60,000; ~8–15% uplift), per Basham Building (NZ-specific 8–15% / $45k+) and international data; premiums decline with builder experience and design-from-outset."
source_location: "§3.3 / §4.2 / §5.3"
- claim: "Recommended model values: baseline SHD 50 kWh/m²/yr; high-performance multiplier 0.50 (0.40–0.70) and premium $35,000 ($20–55k); Passive House multiplier 0.12 (0.08–0.20) and premium $60,000 ($45–90k); standard build cost $525,000 (150 m²)."
source_location: "§7 Model Input Recommendations"Building-standard lever — model data (④c building_standards)
From CR_017:
| building_standard | heat_demand_multiplier | capex_premium_nzd_per_dwelling | confidence |
|---|---|---|---|
| standard (H1-2023 baseline) | 1.00 | 0 | — |
| high_performance (Homestar 7–8) | 0.50 (0.40–0.70) | 35,000 ($20–55k) | mult med-high; capex med |
| passive_house (PHI) | 0.12 (0.08–0.20) | 60,000 ($45–90k) | mult high; capex med |
Neobiome Intelligence relevance
Fills ④c building_standards (the D17 lever). This firms the spec’s placeholders (high_performance was 0.55/25k → **0.50/35k**; passive_house was 0.15/60k → **0.12/60k**). The lever is the efficiency-first core of the self-sufficiency argument — it trades demand reduction against added supply: at the 50-household pilot, choosing high-performance (~35k/dwelling ≈ 1.75M) roughly halves the ~2,900 kWh/hh space-heat demand the engine must otherwise generate and store.
Apply the multiplier as a RATIO (baseline-mismatch caveat). CR_017’s “1.0” is a post-2023 H1 code build heated to comfort (~50 kWh/m²/yr); CR_015’s heat_space_kwh_hh (~2,900 kWh/hh Tasman) is existing-stock under-heated actual demand. Use CR_017’s multiplier (0.50 / 0.12) as a proportional reduction on CR_015’s absolute baseline — accurate as a ratio, but note it slightly overstates absolute kWh saved because the under-heated baseline is already low. A “heat to health standard” scenario would raise both the baseline and the absolute savings.
Caveat for calculation use. PH multiplier is robust (PHINZ/Basham/Jason Quinn converge on ~90% reduction); the capex premiums are MEDIUM — HP from 2018 BRANZ data inflation-escalated, PH largely from one NZ builder (Basham) + international. Real custom builds can exceed the ranges ($60–120k for a 200 m² PH); premiums are declining with builder competency.
Research targets
Documents to retrieve
- BRANZ SR385 — Industry Perspectives on Exceeding the Minimum — the NZ Homestar cost-premium primary behind the high-performance capex (Homestar 6/7/8 =
12k–47k, 2018). WebFetch-retrievable (BRANZ cloudfront PDF). New target RT_205; firms the HP capex from medium → sourced. - BRANZ SR483 — Measuring Our Sustainability Progress (2023) — empirical stock space-heat demand by city (the baseline anchor). Cross-ref; no separate RT.
- Jason Quinn / Sustainable Engineering — Passive House for New Zealand (2019) + PHINZ — the PH case-study SHDs and 90%-reduction claim. Cross-ref.
Research gaps
- Post-2023 H1 code baseline SHD not independently measured — derived from MBIE “Building for Climate Change” caps + Formance, not from monitored new-code builds. BRANZ SR483 is existing-stock.
- PH capex premium NZ data is thin (largely one builder + international) and declining; a current multi-builder NZ PH cost study would firm it.
Connections
Links to
Referenced by