What is H1 Compliance and Why It Matters
H1 compliance refers to meeting the requirements set out in Clause H1 of the New Zealand Building Code, which governs energy efficiency in buildings. Whether you're building a new home, retrofitting an existing one, or working on a commercial development, H1 compliance ensures your building minimises heat loss, conserves energy, and stays comfortable year-round.
What is the H1 Standard?
The H1 standard defines the minimum energy efficiency performance for all new buildings in New Zealand. It sets out thermal insulation requirements, heating and cooling efficiency targets, and ensures a building's design supports long-term energy performance.
What is a H1 Report and When Do You Need One?
A H1 report is a formal assessment used to demonstrate that your building design complies with H1 requirements. It typically includes thermal calculations (R-values, U-values), energy modelling, and analysis of climate zone-specific performance. You'll need a H1 report for most new builds, renovations, or when applying for building consent.
Recent Changes to the H1 Standard in New Zealand
What Are the Key Changes to Insulation Requirements in NZ?
The 2021–2023 changes to Clause H1 raised the bar significantly. New minimum insulation values were introduced for walls, floors, roofs, and glazing. These changes were aimed to reduce heating demand by up to 40% compared to previous versions.
When Were the Latest H1 Updates Released?
The updated standards were released in November 2021, with staged implementation through to May 2023. These updates align with New Zealand's goals for carbon reduction and better-performing housing stock.
But let's be honest—while the last major update set out to raise the bar, we’re already seeing proposed revisions just two years later. That raises the question: were the targets ever truly met?
From our view, the industry did an incredible job adapting during the last update cycle—but much of that effort seems to have gone unnoticed. At BEO Buildingscience, we chose not to make another formal submission this time. Why? Because our position hasn’t changed: performance and comfort matter most. Compliance is just a piece of paper—we’ll help you get it, no worries.
What’s Next: MBIE’s Latest Consultation on Insulation Requirements
In December 2024, MBIE released a consultation document proposing amendments to Acceptable Solutions H1/AS1 and H1/AS2, and Verification Methods H1/VM1 and H1/VM2. The review focuses on:
- Removing the schedule method to encourage more cost-effective, performance-based modelling
- Adjusting R-values for specific scenarios, such as bathrooms with underfloor heating
- Improving clarity around thermal bridging, floor area calculations, and treatment of mixed-use buildings
These proposed changes aim to balance upfront building costs with long-term energy savings while increasing consistency in the consenting process. Feedback was open until 28 February 2025. While we didn’t submit feedback this time, we’re on board with whatever changes come into play—because we’re here to support performance-driven outcomes above all. Compliance is easy—we’re happy to handle that part so you can focus on designing spaces that work.
H1 Compliance for All Building Types
Does H1 Apply to Commercial Buildings Too?
Absolutely. H1 applies to all new buildings, including residential, commercial, industrial, and mixed-use structures. Specific compliance pathways exist for large commercial projects, often involving advanced modelling.
Glazing and Insulation Requirements Explained
Is Triple Glazing Now Mandatory in New Zealand?
Triple glazing is not mandatory—and to be clear, it's not even required for H1 compliance. Good quality double glazing can easily meet or exceed the performance of poorly made triple glazing. What matters more is the actual thermal performance, not the number of panes.
That said, triple glazing can make sense in specific situations: Passive House projects in the South Island, buildings targeting high performance standards, or in urban areas where acoustic control is critical. Just keep in mind—it’s heavier, impacts window and structure design, and comes with added cost. If you’re going that route, make sure you’re getting real performance for your money. Look for a centre-of-glass U-value between 0.5–0.8 W/m²K to justify the upgrade.
What is the Minimum R-Value for Walls?
Officially, H1 sets the minimum R-value for walls at R2.0 across all climate zones. But in practice? That’s rarely enough. Most standard timber-framed walls—when modelled using actual construction values rather than theoretical ones—need at least R2.6 to truly comply. We recommend going a step further and using R2.8 insulation as a baseline.
What is the Minimum Insulation Required for a Roof?
This one’s been the biggest headache. Officially, the requirement is R6.6 in the coldest zones—but meeting that in real buildings is another story. To actually achieve that level of performance once you account for thermal bridging, the insulation itself often needs to be R7–R8.
The only way to realistically navigate this part is through energy modelling or using VM1 or VM2. Compliance aside, it’s about getting the roof build-up right—especially where E3 risks come into play due to poorly matched vapour control and insulation layers.
Is 100mm of Roof Insulation Enough?
Generally, no. 100mm of standard insulation will not meet the new roof R-value requirements. Even the best insulation materials like PIR or PU boards top out around R5 at 100mm thickness.
Thermal Performance: U-Values and How to Measure Them
How to Measure U-Value for Compliance
U-value is the inverse of R-value and tells us how much heat flows through a building element. For opaque assemblies—like walls, roofs, and floors—we calculate this directly using tools such as PHPP or free tools like Design Navigator.
But windows are more complex. You’ll need to account for frame type, glazing unit, gas fill, edge spacers, and more. With the schedule method potentially being removed, understanding these components will become essential across the industry.
Next up: perimeter Psi values. Floor edge losses are becoming a major factor, and we expect the industry to shift toward either custom modelling or more realistic lookup tables for slab calculations.
Why U-Value Matters in Achieving H1 Compliance
Accurate U-values ensure your building is actually performing—not just ticking a compliance box. They affect everything from comfort to cost, and we use them to optimise insulation strategies where they matter most.
Need Help Navigating H1 Compliance?
Our Services: Energy Modelling, H1 Reports, and Design Reviews
- Energy modelling for residential and commercial projects
- Design reviews and insulation strategy optimisation
- Slab edge calculations and thermal bridging analysis
- Full H1 documentation for building consent
Work With Us to Make Your Project H1 Compliant – Without the Guesswork
Whether you’re preparing a new project or adjusting for a building consent resubmission, we’ve got you covered. H1 doesn’t have to be confusing or expensive.
Let’s make your building smarter, healthier, and fully compliant. Reach out today to talk through your project.
