Disclaimer:
This article provides general information only and does not constitute financial, legal, tax, or investment advice. Property investment involves risk. Always do your own research and seek personalised advice from qualified professionals before making investment decisions.
Key Takeaways
- All private rentals must comply with the Healthy Homes insulation standard, subject to the specific exemptions.
- Ceiling and underfloor insulation is compulsory in rental homes, with specific exemptions for some areas or circumstances.
- Minimum Healthy Homes R-values depend on the applicable climate zone; newer consented work may need to meet the higher Building Code requirements.
- Some existing insulation can comply if it meets the applicable evidence, R-value or thickness tests and remains in reasonable condition.
- New or renewed tenancy agreements must include a signed statement describing the property’s current level of Healthy Homes compliance.
- Non-compliance can result in Tribunal orders and financial penalties.
Insulation helps a rental home retain heat. Since 1 July 2025, all private rentals must comply with the Healthy Homes standards, subject to the specific exemptions. Here is what the insulation standard requires.
Why Insulation Matters
Insulation reduces heat loss. Tenancy Services says a better-insulated home will usually cost less to heat, be drier and be less prone to mould. Actual performance and costs depend on the property, installation and use.
For landlords, the immediate issue is meeting and maintaining the legal standard. Non-compliance can lead to enforcement action or financial penalties; tenant, rent, turnover and property-value outcomes are not guaranteed.
Where Insulation Is Required
The standard covers ceiling and underfloor insulation, subject to the detailed requirements and exemptions:
Mandatory Insulation Areas:
- Ceiling: qualifying insulation is required in applicable ceiling areas
- Underfloor: qualifying insulation is required in applicable suspended-floor areas
The Healthy Homes insulation standard focuses on ceiling and underfloor insulation. Separate Building Code requirements can apply to new builds or consented renovations, so check the property records and the scope of any consented work.
Minimum R-Values
R-value measures insulation's thermal resistance; the higher the R-value, the better the insulation performs. The minimum R-values required depend on your property's climate zone.
New Insulation Minimum R-Values:
- Zone 1 (Auckland, Northland, Waikato coast): Ceiling R2.9, Underfloor R1.3
- Zone 2 (Most of North Island, Nelson, Marlborough): Ceiling R2.9, Underfloor R1.3
- Zone 3 (South Island, Central Plateau, Wellington hills): Ceiling R3.3, Underfloor R1.3
If you are unsure which zone your property is in, the MBIE website has detailed maps showing zone boundaries.
Existing Insulation
Existing insulation may comply where the applicable Healthy Homes tests are met. In all cases it must remain in reasonable condition; additional evidence rules apply in some situations:
- It meets the applicable R-value, thickness or documented prior-compliance test
- It is in reasonable condition, with no mould, dampness or damage
- It has no gaps that prevent compliance
Existing ceiling insulation installed before 1 July 2016 generally must be at least 120mm thick. Insulation below 120mm is acceptable only if the landlord can prove it met R2.9 or R3.3, depending on the climate zone, when installed and has not degraded in thickness by more than 30%.
When Existing Insulation Does Not Comply:
- It is water damaged, mouldy, or significantly compressed
- There are large gaps or missing sections
- It has been disturbed and not properly reinstated
- Rodents or pests have damaged it
Exceptions and Exemptions
The regulations contain specific full or partial exemptions. Do not assume an exemption from a rule of thumb; check the official criteria and retain supporting evidence:
When Insulation May Not Be Required:
- Impracticable or unsafe access: an area a professional installer cannot reasonably access or insulate without the specified risks or substantial work
- No applicable suspended-floor area: for example, a concrete slab has no underfloor space to insulate
- Existing compliant underfloor insulation: a partial exemption can apply where required compliance documents and reasonable condition tests are met
- Habitable space above or below: applicable ceiling or floor areas may be exempt; limited ceiling cavities can have separate compensation rules
If an exemption applies, describe the property’s current compliance position in the signed statement and keep the records that support the exemption. Some exemptions last only while the relevant circumstances continue.
Installation Considerations
Insulation must be installed correctly to be effective. Poor installation can significantly reduce performance and even cause problems.
Installation Best Practice:
- ☐ Use an installer competent for the work and follow NZS 4246:2016 and product requirements
- ☐ Ensure insulation fits snugly without gaps or compression
- ☐ Follow NZS 4246:2016 and fitting-specific requirements around downlights and other heat sources
- ☐ Have electrical safety issues assessed by an appropriately authorised person
- ☐ Fix any moisture issues before installing underfloor insulation
An installer can assess the property and provide installation records. Keep assessments, measurements, calculations, invoices, certificates and photographs that demonstrate compliance.
Compliance Statements
New or renewed tenancy agreements must include a signed statement describing the property’s current level of compliance with all Healthy Homes standards, including insulation.
Use the current Tenancy Services statement requirements to record the insulation location, type and relevant R-value or thickness information, plus any exemption. Keep supporting records and provide requested compliance information to a tenant within 21 days.
Costs and Funding
Insulation cost depends on the property, access, existing condition, product, safety work and installer. Obtain property-specific written scopes and quotes rather than relying on generic price bands:
- Confirm which ceiling areas require work and what evidence will be supplied
- Confirm which underfloor areas require work and whether an exemption is being relied on
- Compare the same scope, product specification, safety work and documentation across quotes
Funding eligibility and programme terms can change. Check current EECA guidance for the property and applicant rather than assuming a rental property qualifies.
The Bottom Line
All private rentals have had to comply with the Healthy Homes standards since 1 July 2025, subject to the specific exemptions. A landlord who does not meet an applicable obligation is in breach of the Residential Tenancies Act and may face enforcement action or a financial penalty; the outcome is case-specific.
If compliance is uncertain, use the official insulation tool, check records and arrange a competent assessment. Remedy confirmed gaps and document the result; do not assume an exemption or compliant R-value without evidence.
Compliant insulation supports heat retention, but it does not guarantee higher rent, lower turnover, lower maintenance costs or increased property value. Treat installation as a compliance and property-condition decision, with costs assessed for the specific home.