Ceiling and underfloor insulation has been compulsory in all rental homes since 1 July 2019. The healthy homes insulation standard builds on the current regulations and some existing insulation will need to be topped up or replaced. 

Depending on location, ceiling insulation needs to meet minimum R-values (‘R’ stands for resistance – an R-value is a measure of how well insulation resists heat flow). Existing ceiling insulation that was installed before 1 July 2016 needs to be at least 120mm thick. Underfloor insulation needs a minimum R-value of 1.3.

Insulation stops heat escaping from the house. In general, the better insulated a rental home is, the more it will retain heat. This means it will usually cost less to heat the property, and the property will be drier and be less prone to mould.

Note: Ceiling and underfloor insulation is already compulsory in rental homes. Find out about the current insulation requirements for rental properties

All private rentals must comply within 90 days of any new or renewed tenancy after 1 July 2021, with all private rentals complying by 1 July 2024. All boarding houses must comply by 1 July 2021. All houses rented by Housing New Zealand and registered Community Housing Providers must comply by 1 July 2023.

Download the insulation guidance document. [PDF, 2.6 MB]

What is the required level for insulation?

Insulation requirements under the healthy homes standards (which align to the 2008 Building Code) are measured by R-value. R-value is a measure of resistance to heat flow. The higher the R-value, the better the insulation.

Minimum R-values vary across New Zealand. Check what zone your property is in using the map below.

Map of New Zealand climate zones

Zone 1 — ceiling R 2.9, underfloor R 1.3

Zone 2 — ceiling R 2.9, underfloor R 1.3

Zone 3 — ceiling R 3.3, underfloor R 1.3

You can check the R-value of new insulation by checking the product packaging. For existing insulation, you can check the thickness yourself (existing ceiling insulation that was installed before 1 July 2016 must be at least 120mm thick) or consult a professional insulation installer.

Insulation must be installed in accordance with NZS4246:2016 and must be in a reasonable condition, with no mould, dampness, damage or gaps.

New Zealand Standard 4246:2016 [PDF, 6 MB]

Exemptions to the insulation standard

There are three specific insulation exemptions. The information here is an overview. More information on these exemptions is available in Subpart 3 of the Healthy Homes Standards Regulations (external link) .

  1. Access is impracticable or unsafe
    Some areas of some homes may be impracticable or unsafe to access due to their design, limited access, potential for substantial damage, or health and safety reasons. There is an exemption for parts of homes where a professional installer is unable to access and/or insulate, until this becomes possible (for example when a property is re-roofed). 
  2. Partial exemption for certain underfloor insulation
    If the rental home has existing underfloor insulation that was installed when the home was built or converted and this insulation is still in reasonable condition. Landlords must have a copy of any compliance documents that shows the home met the requirements of the time, for example:
    - code compliance certificate
    - certificate of acceptance 
    - another relevant compliance document.
  3. Ceilings and floors with other habitable spaces directly above or below 
    The third exemption applies to areas of ceilings or floors where there are other habitable spaces directly above or below (eg another floor of the same property or another apartment). These areas do not require insulation to meet the healthy homes insulation standard.

These three exemptions are in addition to the general exemptions.

General exemptions to the healthy homes standards

Landlords who have installed new insulation since 1 July 2016 should already meet the requirements of the 2008 Building Code, so they won’t need to do anything further to comply with the healthy homes standards. Landlords should still check that the insulation is in a reasonable condition.

Use our online tool to step you through whether or not you are likely to need to take action to comply with the insulation requirements under the healthy homes standards.

Online tool: Do you need to upgrade your insulation to meet the healthy homes standards?

All existing insulation must still be in reasonable condition to meet the requirements. This means there should be no mould, dampness, damage or gaps.

Further information

The insulation standard is one of five healthy homes standards.

Find out about the other healthy homes standards:

Heating standard

Ventilation standard

Moisture ingress and drainage standard

Draught stopping standard