Cold, damp rentals are a big reason New Zealand introduced the Healthy Homes standards. They set minimum requirements for heating, insulation, ventilation, moisture and drainage, and draught stopping. This post looks only at the insulation part: what it asks of a rental’s ceiling and underfloor.
If you would rather work through it as a step-by-step list, see our landlord’s insulation checklist. The details below come from the official Tenancy Services insulation standard page, so check it for the current wording, because the rules were amended in September 2025.
What the standard covers
The insulation standard applies to ceilings and to suspended floors, the kind where there is a gap between the floor and the ground. Insulation in those spaces has to:
- Reach the minimum R-value for the property’s climate zone
- Be in reasonable condition
- Be installed to the New Zealand standard for bulk insulation, NZS 4246:2016
From 1 July 2025, all private rentals must meet the healthy homes standards, according to the Tenancy Services compliance page.
What an R-value is
R-value measures how well insulation resists heat flow. A higher number means better resistance. It depends on the material and its thickness, which is why two products of the same thickness can have different R-values.
Minimum R-values
Tenancy Services splits the country into three climate zones, and the minimums are:
| Zone | Area | Ceiling | Underfloor |
|---|---|---|---|
| Zone 1 | Top of the North Island | R2.9 | R1.3 |
| Zone 2 | Coastal areas of the North Island | R2.9 | R1.3 |
| Zone 3 | Centre of the North Island and the whole South Island | R3.3 | R1.3 |
The zone map on the Tenancy Services page is the place to confirm which zone your property sits in.
Older insulation
Ceiling insulation installed before 1 July 2016 has to be at least 120mm thick. Thinner existing insulation can still be acceptable if it met the required R-value when it was installed and has not degraded by more than 30%.
That second part is the sort of thing that is hard to judge from the hatch. If you are not sure, an assessment is the safer route.
Reasonable condition
Existing insulation has to be in reasonable condition. The Tenancy Services wording is that there should be no mould, dampness, damage or gaps. Insulation that was fine ten years ago can fall short today because it has shifted, got wet or been disturbed. Our post on signs your insulation needs replacing covers what that looks like.
Where exemptions apply
The standard does not require insulation everywhere regardless of circumstances. Tenancy Services lists exemptions, including:
- Areas a professional installer cannot access or insulate, for example because of the design of the building, limited access, a risk of damage or safety concerns
- Ceilings or floors with another habitable space directly above or below
Exemptions have conditions, so read the official page before assuming one applies to your rental.
What happens if a rental falls short
Tenancy Services says landlords who breach their obligations can face penalties of up to $7,200. The insulation details also feed into the compliance statement that goes in tenancy agreements, which we cover in the landlord checklist.
How Coastline can help
We can help with the insulation your rental needs and arrange a Healthy Homes assessment for you. Our retrofit insulation includes ceiling insulation with Knauf batts and underfloor insulation with Mammoth, plus Insulfluff removal where old loose fill has to come out first.
Most ceilings take 1 to 3 hours, and an underfloor job for a 100m² home typically takes a day. As a guide, ceilings for a 100m² home usually cost $1,600 to $2,000 and underfloors $2,200 to $2,500. Your quote depends on access and materials.
Ask for a quote
If you own a rental in the Bay of Plenty, Coromandel and Hauraki, Gisborne and the East Coast, or the Rotorua and Taupō area, request a free, no-obligation quote. We aim to call you back within 48 hours, or you can call 027 482 0333.