Last Updated: 2 November 2026
Insulation requirements in Christchurch and Canterbury depend on where your property is and whether you are building, renovating or improving an existing home. New homes must meet Building Code Clause H1 for energy efficiency. Existing homes do not automatically need to be upgraded whenever H1 changes. Rental properties have separate Healthy Homes obligations, generally requiring ceiling and suspended underfloor insulation wherever reasonably practicable. [1, 7, 10]
Christchurch is in H1 climate zone 5, but Canterbury also includes locations in zones 3 and 6. There is also an H1 transition ending on 26 November 2026, which affects how new building designs demonstrate compliance. [1, 5]
This guide explains the current rules, what the R-values mean and how to choose an appropriate upgrade for your property.
Which insulation rules apply to your property?
The first step is to identify the type of work you are planning.
| Your situation | What to consider |
|---|---|
| Building a new home | The new building must meet H1. Your designer specifies the construction and demonstrates compliance using an appropriate pathway. |
| Adding an extension or carrying out a substantial renovation | New construction must meet current requirements. The untouched house does not automatically need a complete upgrade. |
| Improving an existing owner-occupied home | A change to H1 does not itself require a whole-house retrofit. Assess existing performance and the requirements applying to the proposed work. |
| Upgrading an existing rental | Meet the Healthy Homes insulation standard and any Building Code obligations triggered by building work. |
| Building a new rental | Meet the Building Code for the new building and the applicable Healthy Homes requirements before renting it out. |
The scope of an alteration matters. Replacing a small part of a building and constructing a new extension are assessed differently. Your designer or council can confirm the appropriate approach. [7, 8]
What climate zone is Christchurch and Canterbury in?
Christchurch, including Banks Peninsula, is in H1 climate zone 5. So are most of the Canterbury districts where Endurance Insulation works. However, Canterbury is not covered by one H1 zone.
| Location or district | H1 climate zone |
|---|---|
| Christchurch City, including Banks Peninsula | 5 |
| Waimakariri and Selwyn | 5 |
| Hurunui | 5 |
| Ashburton, Timaru and Waimate | 5 |
| Kaikōura | 3 |
| Mackenzie | 6 |
| Waitaki | 5 or 6, depending on location |
Waitaki is split at the Otekaieke River: the district on the river’s true left is zone 6 and the true right is zone 5. “True left” and “true right” mean looking downstream. Check the official boundary for the property rather than relying on its nearest town. [5]
Healthy Homes uses a separate three-zone system. Canterbury is in Healthy Homes zone 3, including Christchurch. This is why a rental insulation assessment may say “zone 3” while new-build plans say “zone 5”. [10]
Understanding insulation R-values
An R-value measures resistance to heat flow. A higher R-value means better resistance. However, the number on an insulation pack and the R-value used for Building Code compliance are not necessarily the same.
- Product R-value describes the insulation material at its specified thickness.
- Construction R-value describes the complete roof, wall, floor or window assembly, including the effects of its construction.
For example, placing R2.0 insulation between wall studs does not automatically create an R2.0 wall. Heat also flows through framing and other components. Your designer needs the construction R-value when checking H1 compliance. [6, 18]
Thickness alone is also an unreliable way to compare products. Different materials can provide different R-values at the same thickness. [16]
New-build insulation requirements and the November 2026 transition
H1 sets the required energy performance; acceptable solutions and verification methods provide recognised ways to demonstrate compliance. A compliant design can also use an appropriately justified alternative solution.
As at 2 November 2026:
- H1/AS1 and H1/VM1 sixth editions have been available since 27 November 2025.
- Their fifth editions, Amendment 1, remain available for consent applications submitted before 27 November 2026.
- From 27 November 2026, new applications using H1/AS1 or H1/VM1 must use the sixth editions. [1]
H1/AS1 covers all housing, including houses larger than 300 m². Its 300 m² limit applies to buildings other than housing. [4]
R-values under the fifth-edition schedule method
The following are the minimum construction R-values under H1/AS1 fifth edition, Amendment 1, Table 2.1.2.2B, for elements without embedded heating.
| Building element | Zone 3 — Kaikōura | Zone 5 — Christchurch and most Canterbury districts | Zone 6 — Mackenzie |
|---|---|---|---|
| Roof or ceiling assembly | R6.6 | R6.6 | R6.6 |
| External wall assembly | R2.0 | R2.0 | R2.0 |
| Slab-on-ground floor | R1.5 | R1.6 | R1.7 |
| Other floors, including suspended timber floors | R2.5 | R3.0 | R3.0 |
| Windows and doors | R0.46 | R0.50 | R0.50 |
| Skylights | R0.54 | R0.62 | R0.62 |
These figures apply when the schedule method’s conditions are met, including its glazing restrictions. They are not universal product specifications. Where roof-space restrictions prevent full-thickness insulation above a horizontal ceiling, the roof R-value may reduce to R3.3 within 500 mm of the outer ceiling perimeter. Elements with embedded heating have separate requirements. [3]
The schedule method closes to new applications on 27 November 2026. It is removed from the sixth edition. [1, 2]
How the sixth edition changes the approach
The sixth-edition calculation method assesses the proposed building’s heat loss against a reference building. This allows a designer to balance performance across building elements, within the method’s limits. The modelling pathway under H1/VM1 provides another option. [6]
For context, these are the reference-building R-values used in the sixth-edition calculation equations:
| Reference element | Zone 3 | Zone 5 | Zone 6 |
|---|---|---|---|
| Roof term | R6.6 | R6.6 | R6.6 |
| Wall term | R1.6 | R1.6 | R1.6 |
| Slab-on-ground term | R1.5 | R1.6 | R1.7 |
| Other-floor term | R2.5 | R3.0 | R3.0 |
| Window term | R0.46 | R0.50 | R0.50 |
These are calculation benchmarks, not a list of minimum specifications for each part of your home. The reference roof term also incorporates skylight area. The proposed building must pass the full assessment. [4]
MBIE says the overall level of required energy efficiency remains unchanged. The revised wall benchmark accompanies changes to how wall framing and thermal bridging are assessed; it should not be read as a simple instruction to reduce wall insulation. [2]
For homeowners, the practical step is to ask your designer which edition and pathway the plans use. Then make sure the quoted insulation matches that design.
Does an existing Christchurch home need the latest insulation?
An existing owner-occupied home does not have to meet the latest new-build insulation specifications simply because the rules have changed. However, building work must meet the requirements that apply to it, and an alteration must not reduce the building’s existing level of compliance. [7]
An older home can still benefit from an upgrade even where none is legally required. Start by finding out what is already installed, whether it remains effective and which areas can be improved without major building work.
For example, an older house with accessible roof and subfloor spaces may be a straightforward candidate for ceiling and underfloor improvements. A house with a concrete slab and a shallow skillion roof needs a different approach. [11, 18]
Renovations and extensions
For an extension or substantial alteration, new construction must meet the current requirements. The remainder of the house does not automatically need to be brought up to new-build standards, although changes may be needed to preserve the building’s overall performance. [7]
Removing wall linings can create a useful opportunity to improve insulation that would otherwise be difficult to access. Endurance provides wall insulation services for new builds and renovations where the wall cavities are accessible.
Do insulation upgrades need building consent
Retrofitting insulation into an existing ceiling or subfloor is generally exempt from building consent. External wall insulation and insulation in internal fire separation walls are excluded from that general exemption. External wall work normally needs consent unless the council grants a specific exemption. [9]
Wall upgrades also need careful moisture and durability assessment. The existing cladding, wall underlay and drying arrangements affect what can be installed safely. Plan this with your builder and designer before work begins. [19]
Rental property insulation requirements in Canterbury
All private rentals were required to comply with the Healthy Homes Standards by 1 July 2025, unless an exemption applies. Keeping the property compliant is an ongoing responsibility. [12]
For an existing Canterbury rental requiring new insulation or a top-up, the usual Healthy Homes requirements are:
| Area | Usual requirement |
|---|---|
| Ceiling | Insulation achieving at least R3.3 |
| Suspended underfloor | Insulation achieving at least R1.3 |
| Condition and installation | Reasonable condition, appropriate coverage and installation to NZS 4246:2016, subject to applicable existing-insulation provisions and exemptions |
A routine top-up in an existing rental does not automatically have to achieve new-build H1 levels. Different obligations may apply if it forms part of more substantial building work. [10]
Does older ceiling insulation have to be replaced?
Not necessarily. Ceiling insulation installed before 1 July 2016 may qualify under the older-insulation provisions if it is in reasonable condition and at least 120 mm thick.
A thinner installation may qualify where there is evidence that it originally met the required R-value and has retained at least 70% of its original thickness. The assessment also needs to consider coverage, damage and moisture. A 120 mm measurement alone is not proof that every insulation requirement is met. [10, 11]
What if the roof or underfloor is inaccessible?
Exemptions can apply where a professional installer cannot reasonably and safely install insulation without substantial building work or damage. Areas above or below another domestic living space are treated differently, and a concrete slab does not require suspended underfloor insulation. [11]
A missing access hatch does not automatically create an exemption. Nor does one inaccessible area necessarily exempt the whole house.
A change effective 25 September 2025 also reinstated a partial exemption for certain existing ceiling insulation supported by qualifying compliance documentation. This can affect some homes with limited ceiling space and compensating insulation elsewhere. It is a specific, evidence-based provision, rather than a general exemption for all low-pitched roofs. [11, 13]
Are wall insulation and double glazing compulsory in rentals?
The Healthy Homes insulation standard does not generally require existing rentals to be retrofitted with wall insulation or double glazing. Its insulation obligations focus on ceilings and suspended floors. Building work may create separate requirements, and the other Healthy Homes standards still apply. [10, 12]
For an enclosed subfloor, a ground moisture barrier is also required where reasonably practicable, under the moisture ingress and drainage standard. It controls ground moisture; it does not replace underfloor insulation. [14]
Keep installation records, product details, photographs and evidence supporting any exemption. Required tenancy compliance statements must accurately reflect the property’s current position. [15]
Endurance offers Healthy Homes insulation assessments and ground moisture barrier installation.
Choosing insulation for Canterbury conditions
Canterbury has substantial variation between its coastal areas, plains, foothills and inland basins. NIWA’s regional climatology describes cold winter conditions alongside potentially hot summer weather, with larger temperature ranges in inland areas. [20]
The H1 zone is the starting point for a new design. A useful assessment should also consider the property itself.
Ceiling insulation and roof-space limitations
Check the available depth, existing insulation and required ventilation and safety clearances. A high R-value product must fit correctly: squeezing it into a cavity or leaving gaps can undermine its performance.
Where appropriate, insulation over framing can reduce heat loss through the framing itself. The installation must still suit the roof construction and any lights, wiring or other equipment. [17, 18]
Endurance’s ceiling insulation service can help identify whether a top-up or replacement is appropriate.
Suspended floors and ground moisture
For a timber floor, check that insulation is properly supported and positioned against the underside of the flooring. Missing sections or material that has dropped away need attention. Address moisture sources before covering damaged insulation with another layer. [11, 17]
An assessment should consider underfloor insulation and ground moisture separately, so both heat loss and dampness receive attention.
Walls, concrete slabs and windows in new builds
These elements deserve early design decisions because they can be difficult to improve later. Ask your designer to explain how framing, slab edges, window frames and glazing affect the complete construction’s performance. [18]
For a new Canterbury home, we recommend comparing a compliant design with a higher-performance option before the specifications are finalised. This gives you a clearer picture of the additional upfront cost and expected benefit.
How to check whether your insulation is adequate
A useful assessment checks the insulation’s condition and installation as well as its stated R-value. Cold rooms or high heating bills can prompt a check, but they do not identify the cause on their own.
Ask for an assessment covering:
- What is installed: product type, available labels, installation date and any previous records.
- Where it is installed: ceiling, accessible exterior walls and suspended floor areas.
- Its condition: gaps, compression, dampness, damage and displaced material.
- Installation details: support, fit and clearances around building services.
- Other issues: leaks, ground moisture, draughts, heating and ventilation.
Have insulation rechecked after work in the roof or subfloor, as other trades may have moved it. Use a professional where access or electrical hazards make inspection unsafe. [16, 17]
For a rental, ask the assessor to identify the basis for compliance or any exemption. For a new build, compare the installed products and details with the consented specification.
Is it worth insulating above the minimum?
Higher insulation performance can reduce heat loss and improve comfort, but the benefit depends on the whole home. EECA encourages homeowners improving existing ceilings to consider going above minimum requirements where practical. [16]
Our recommendation is to compare options that suit your property rather than choosing solely by the lowest compliant R-value. Consider the extra cost, available space, installation quality and how long you expect to use the home.
For a new build or major renovation, it can make sense to prioritise areas that will become inaccessible. For an older home, correcting gaps or damaged insulation may be the first worthwhile step.
Insulation also works alongside effective heating, ventilation, moisture control and appropriate window design. It does not fix a roof leak or remove the need to ventilate the home. [14, 18]
Endurance supplies and installs glasswool, polyester and wool insulation products, including Knauf Earthwool, Mammoth, GreenStuf, Terra Lana, Pink Batts and Premier TemperTherm. Product selection depends on the location, construction, required performance and budget.
Frequently asked questions
Does “double glazed” mean a window meets H1?
No. H1 assessment uses the performance of the window assembly, including the frame and glazing. Double glazing is a description of the glass arrangement, not proof of a particular construction R-value. Ask the supplier for the performance information required by your designer. [4, 6]
Can insulation be topped up instead of removed?
Yes, where the existing material is suitable to retain. Its condition, compatibility and remaining performance need assessment. Deal with dampness or damage first; adding another layer over a problem does not resolve it. [11]
How much does an insulation upgrade cost?
The cost depends on the area, access, existing insulation, selected products and whether removal or moisture work is needed. A site-specific quote is more useful than a general price per square metre. Endurance Insulation provides free assessments and quotes.
Are insulation grants available?
Some owner-occupiers may qualify for EECA’s Warmer Kiwi Homes programme. Eligibility includes owning and living in a home built before 2008, alongside other criteria. Use EECA’s eligibility checker for the current conditions and approved-provider process. [21]
Will a home already consented under the fifth edition need redesigning after November 2026?
The transition relates to the consent application date. The fifth edition can be used for applications submitted before 27 November 2026. The transition does not, by itself, require an already consented home to be redesigned. Check proposed changes to an existing consent with your designer and building consent authority. [1]
Get insulation advice for your Canterbury property
Whether you are upgrading an older Christchurch home, managing a rental or planning a new build, Endurance Insulation can help you understand the practical options.
We supply and install ceiling, wall and underfloor insulation, provide insulation removal and upgrades, and work with homeowners, landlords and builders across Christchurch, Ashburton, Timaru and wider Canterbury. We also provide new build insulation.
Request a free insulation assessment and quote, or call 021 081 37620. For a new build, have your plans and insulation specifications ready so we can discuss products that suit the design.
Sources & References
Regulatory information checked on 2 November 2026. Dates below are publication or update dates where stated by the source.
- MBIE Building Performance — H1 Energy efficiency. Current editions and transition dates. Official H1 guidance.
- MBIE — Increasing the flexibility of H1 energy efficiency. Published 27 November 2025. H1 changes and performance objectives.
- MBIE — H1/AS1 fifth edition, Amendment 1. Effective 4 August 2022; available for applications submitted before 27 November 2026. See Table 2.1.2.2B and schedule-method limitations. Official PDF.
- MBIE — H1/AS1 sixth edition. Effective 27 November 2025. See scope, Table 2.1.2.7, component limits, heated-element provisions and Appendix D. Official PDF.
- MBIE — Weather files for Aotearoa New Zealand. District assignments to the six H1 climate zones; also see H1/AS1 Appendix C for boundaries. Climate-zone guidance.
- BRANZ — H1/AS1 sixth edition calculation method tool. Calculation-method scope, trade-offs and construction R-values. Technical guidance.
- MBIE Licensed Building Practitioners — Achieving H1 Energy efficiency compliance when altering an existing building. New construction and existing-building obligations. Alterations guidance.
- MBIE — Repairs and replacements — H1 Compliance. Requirements depend on the extent and circumstances of the work. Repairs and replacements guidance.
- MBIE — 5.1 Thermal insulation. Schedule 1 consent exemption and exclusions. Building consent guidance.
- Tenancy Services — Insulation standard. Updated 25 September 2025. Rental insulation requirements.
- Tenancy Services — Healthy Homes Standards Insulation guidance. Current linked guide, including existing insulation and exemptions. Official PDF.
- Tenancy Services — Healthy homes compliance. Updated 1 July 2025. Deadlines and ongoing obligations.
- Tenancy Services — Minor changes to the healthy homes standards. Published 18 September 2025; changes effective 25 September 2025. Amendment explanation.
- Tenancy Services — Moisture ingress and drainage standard. Updated 25 September 2025. Ground moisture barrier requirements.
- Tenancy Services — Compliance statement. Required rental compliance information.
- EECA — Insulate your home to improve energy efficiency. R-values, retrofit advice and insulation performance.
- MBIE — Installing insulation. Updated 31 March 2025. Installation quality, inspection and safety.
- MBIE — Insulating your home. Updated 9 August 2023. Used for general technical guidance, rather than current transition dates. Thermal bridging and upgrade planning.
- MBIE — Existing building compliance level after retrofitting insulation. Wall moisture, drying and durability considerations.
- NIWA — The climate and weather of Canterbury. G. R. Macara, 2016, second edition, NIWA Science and Technology Series 68. Regional climatology and report.
- EECA — Warmer Kiwi Homes eligibility. Current grant eligibility checker.
Company service, product and quotation information was checked against Endurance Insulation’s website, product range, frequently asked questions and the service pages linked above.
