New Zealand's H1 insulation requirements changed significantly in November 2025 — and if you're a builder, insulation contractor, or renovator, the countdown clock is ticking. The 12-month transition period ends 1 November 2026, after which only the new H1 AS1 and AS2 editions will be accepted by building consent authorities (BCAs). Here's everything you need to know to stay compliant and keep winning work.
What Is H1 and Why Does It Matter?
H1 is the energy efficiency clause of the New Zealand Building Code, administered by the Ministry of Business, Innovation and Employment (MBIE). It sets the minimum thermal performance standards for new residential and commercial buildings — covering insulation in ceilings, walls, floors, and the performance of glazing.
Getting H1 right isn't optional. A building that fails to comply won't get code compliance, and that means no CCC for your client. As the trade doing the install work, responsibility can land squarely on you if the spec was wrong from the start.
What Changed in November 2025?
MBIE published updated versions of H1 Acceptable Solution 1 (AS1) and Acceptable Solution 2 (AS2) in late 2025. These revisions built on the major 2021–2022 overhaul that dramatically increased R-value requirements across most of New Zealand's six climate zones.
Key updates in the new editions include:
Revised R-value schedules. The new AS1 tables clarify R-value requirements by construction type — light timber frame, steel frame, and concrete/masonry — in each climate zone. Some configurations now require higher total R-values than previously specified to account for thermal bridging through framing.
Updated climate zone guidance. Zone boundaries and typical weather data have been refreshed. If your work straddles a zone boundary (common for build sites in Central Plateau, parts of Canterbury, and Southland), check the updated maps on the Building Performance website rather than relying on old printouts.
Window and glazing performance. The new editions update requirements around U-values and solar heat gain coefficients for glazing. Builders spec'ing aluminium joinery need to confirm the product meets the new thresholds — not all products that passed previously will pass now.
Mechanical ventilation interaction. There's tightened guidance on how airtightness and mechanical ventilation interact with H1 compliance. High-performance builds using HRV or ERV systems should confirm their documentation method under the new framework.
The Transition Timeline
MBIE operates a 12-month parallel-running period to let the industry adapt:
| Period | Status |
|---|---|
| 1 November 2025 – 31 October 2026 | Either old or new H1 editions accepted |
| From 1 November 2026 | New editions only — old versions no longer accepted |
This means any building consent submitted from 1 November 2026 must use the new AS1 or AS2 documents. Building consent applications in progress under the old editions should be checked — if the consent is still being processed after the cutoff, BCAs may require updated documentation.
The practical advice: transition to the new editions now, rather than waiting. Doing it in the middle of a busy spring-summer season will be more painful.
What This Means for Insulation Contractors
If you're installing batts, board insulation, or underfloor insulation as a subcontractor, you may not be responsible for the design — but you are responsible for installing what was specified and nothing less.
Check the spec sheet before you quote. If a builder hands you a spec that references old H1 tables, flag it. Installing to a deprecated spec could leave you caught in a dispute if the building doesn't achieve compliance.
Document your installs. Keep records of product type, R-value, thickness, and brand for every job. If a compliance issue arises later, that paperwork protects you. A job management app like Fastcrew makes it easy to attach photos and product specs to each job, so everything's in one place if you ever need to prove what was installed and when.
Thermal bridging is now harder to ignore. The new editions are more explicit about accounting for framing that reduces effective R-values. If you're quoting insulation for a wall or ceiling, factor in the builder's framing schedule — a spec that looks compliant on paper may fall short if it doesn't account for steel framing or dense timber nogs.
Opportunities for the Winter Season
It's May in New Zealand, which means the cold is arriving fast — and homeowners are thinking about heating bills. That's good news for insulation contractors and builders offering retrofit work.
The demand for ceiling and underfloor insulation upgrades is strong heading into 2026 winter for several reasons:
- Healthy Homes compliance continues to drive rental property upgrades across the country. Landlords who haven't yet met the ceiling insulation standard face significant penalties.
- Energy costs remain elevated, and homeowners are motivated to cut bills.
- The new H1 requirements are prompting renovators to upgrade insulation in older homes as part of broader works, especially before BCAs shift fully to the new standard in November.
If you're pricing retrofit insulation jobs this winter, remember to factor in scaffolding or access costs for ceiling work, and disposal of old fibreglass batts if you're replacing them. For guidance on building your job cost, see our job costing guide for NZ tradies.
Pricing and Claiming H1 Insulation Work
For tax purposes, insulation installed as part of a new build is a standard trade cost — materials and labour claimed against business income. For retrofit insulation on rental properties, the IRD has specific guidance on whether the work is a repair/maintenance claim or a capital improvement.
The general rule: if you're upgrading insulation in an existing structure (not replacing like-for-like), it's likely capital and claimed via depreciation rather than as an immediate deduction. However, the 20% Investment Boost deduction introduced in May 2025 may apply if the work meets MBIE's criteria for energy efficiency improvements. Always confirm with your accountant.
GST-registered businesses claim the GST back on materials in the usual way. If you're not sure whether you should be GST registered, use our GST calculator to check your turnover against the $60,000 threshold.
For a broader look at how energy efficiency work creates tradie business opportunities, see our article on NZ's energy efficiency opportunity for tradies.
Quick Reference: H1 Checklist for Builders
Before your next consent application:
- [ ] Confirm you're using the new H1 AS1 or AS2 documents (November 2025 editions)
- [ ] Verify your site's climate zone using MBIE's updated zone maps
- [ ] Check total R-values for your wall, ceiling, and floor assemblies under the new tables
- [ ] Confirm glazing products meet updated U-value and SHGC requirements
- [ ] If using steel framing, apply the correct thermal bridging correction factor
- [ ] Document your insulation install with photos and product data sheets
Get Your Business Ready
With the November 2026 hard cutover six months away, now is the right time to update your standard H1 specs and brief your subbies. Download our free NZ tradie templates at tradietools.nz/templates/ — including specification checklist templates that can be adapted for H1 compliance documentation.
NZ Tradie Tools provides free calculators, templates and guides for New Zealand tradies. Visit tradietools.nz.
Not sure if your quote is fair? Use our free NZ tradie quote checker to compare any quote against typical rates for your city and job type.