Industry Insights webinar | Update from MBIE - Changes to the H1 building code

H1 Compliance Tightens

New Zealand's Building Code clause H1 governs energy efficiency in buildings, aiming to reduce heating needs, cut emissions, and improve living conditions in a country with high household energy costs and cold, damp winters. The most recent major shift occurred in late 2025 when the Ministry of Business, Innovation and Employment (MBIE) finalised updates to the Acceptable Solutions (H1/AS1, H1/AS2) and Verification Methods (H1/VM1, H1/VM2).

These changes built on a July 2025 announcement to scrap the Schedule Method—a simple table-based approach long favoured for its ease in specifying insulation levels for roofs, walls, floors, and glazing. The method's removal pushes the sector toward calculation-based or modelling compliance, which better accounts for real-world factors like thermal bridging from timber framing (now pegged at 38% content in some assessments, lowering effective R-values).

The updates took effect immediately on 27 November 2025, but a transition period runs until 26 November 2026. Building consents submitted before that date can still use the older fifth-edition rules; afterwards, the sixth edition becomes mandatory. This creates urgency for architects, designers, builders, and developers planning projects, as switching mid-stream risks delays or rework.

Real-world impacts fall hardest on residential and small commercial builders (under 300 m²), where upfront costs for higher-performance insulation, better glazing, or advanced modelling rise—though long-term energy savings and health benefits (drier homes, lower bills) offset some expense. Tensions exist between affordability goals and emissions reduction targets; critics argue the changes burden an already strained construction sector, while supporters highlight improved clarity in measurements (using internal dimensions) and exemptions (like for bathroom heating).

Non-obvious angles include the push toward modern materials and methods—such as structural insulated panels (SIPs)—that perform better under the new rules, potentially reshaping supply chains and design preferences. The changes also reflect broader climate policy, aligning building standards with New Zealand's net-zero ambitions without fully mandating the most stringent overseas benchmarks.