H1/AS1 5th vs. 6th Edition: What Changed and How to Navigate the Transition

The Short Answer:

With the H1 6th Edition fully replacing the Fifth Edition for new building consent applications, understanding the shift is critical.

While it introduces stricter baseline assumptions—like the removal of the Schedule Method and a shift in reference wall values—it is not all bad news. With the right thermal modeling approach, the Sixth Edition can actually unlock significant cost-saving opportunities for your build.

At Reshaped Consulting, we help architects and developers navigate this transition nationwide. Here is your practical breakdown of what changed, what you don't need to panic about, and how to stay ahead.

Key Differences: H1/AS1 5th Edition vs. 6th Edition

A quick reference of the structural changes affecting thermal compliance:

Topic	Fifth Edition (Amendment 1)	Sixth Edition (Current)
Available Methods	Schedule Method, Calculation Method, or H1/VM1 Modelling.	Schedule Method removed. Calculation Method and H1/VM1 Modelling only.
Modelling Method (H1/VM1)	Available as an alternative pathway with older reference baselines.	Still fully active and updated to align with stricter baseline reference standards and thermal bridging rules.
Reference Opaque Wall	R2.0 for the walls across all climate zones.	R1.6 across all climate zones, reflecting updated framing rules.
Framing Assumptions	NZS 4214 applied; some junction/corner framing could be excluded.	Must assume at least 38% wall framing unless proven otherwise.
Trade-Off Minimums (only for the calculation method)	Percentage rule: elements needed 50% of reference R-value.	Direct minimums: Roof R2.6, Wall R1.0, Non-slab floor R1.3.
Windows & Doors	Listed in Appendix E.	Moved to Appendix D and updated for modern specs.

Can I still use the Schedule Method under the H1/AS1 Sixth Edition?

No. Under the Fifth Edition, many builders and designers relied on the Schedule Method as a fast, rough-and-ready checkbox for compliance. With the Sixth Edition, the Schedule Method has been completely removed.

For many, this caused initial panic because H1 can no longer be an afterthought—it has to be integrated into the design from the start. However, for your bottom line, this is actually a massive silver lining.

If you want to save money on your build—whether through optimized insulation levels, using non-thermally broken glazing where appropriate, or skipping expensive slab-edge insulation—relying on rigid checklists is out.

Moving to the Calculation Method or, more powerfully, the Modeling Method gives you the flexibility to trade off elements intelligently. What looks like a stricter standard on paper often translates to real material cost savings when modeled properly.

How does the 38% wall framing assumption affect my H1 calculation?

One of the most talked-about technical shifts in the Sixth Edition is the default assumption of at least 38% wall framing (including studs, dwangs, plates, and corners) unless a lower whole-building fraction is specifically demonstrated.

It sounds intimidating—many designers worried this would force every project into 140mm framing, double strapping, or expensive thermal breaks just to pass.

The reality on the ground: From the modeling reports we’ve run so far, this is not the massive roadblock people feared. Especially if your project is in Climate Zone 1 or 2, the framing shift hasn't required drastic changes to insulation products. It has largely been business as usual. If you are using the Modelling Method, you don't need to worry about being penalised into over-specifying your walls.

Do I need to rush to submit old plans before the Fifth Edition transition ends?

If you are holding older architectural plans and wondering if you need to desperately rush them through to scrape in under legacy rules, take a breath.

While transitioning an older project requires a proper review rather than just a quick cover-sheet relabeling, you don't need to panic.

Some aspects of compliance are getting tougher under the Sixth Edition, but other pathways are opening up. With the right combination of inputs and thermal modeling, we can get virtually any design to comply without compromising your architectural vision or forcing you to shrink your windows.

Get Expert H1 Guidance Without the Headaches

Navigating the H1 6th Edition compliance doesn't mean you have to sacrifice your design or over-spend on materials. Whether you are reviewing an existing concept or starting a brand-new residential or commercial project anywhere in New Zealand, we are here to help.

Have questions or concerned about how the Sixth Edition affects your plans? Contact us today for a free, no-obligation chat about your project compliance.