“Insulation standards” can mean a few different things in New Zealand, depending on whether you are building, renting out a home or just getting insulation installed. Here is how the three main sets of rules fit together, and which one is likely to matter for you.
Three sets of rules, three situations
| Your situation | What applies |
|---|---|
| Building a new home | Building Code clause H1 (energy efficiency) |
| Renting out a home | The Healthy Homes insulation standard |
| Installing insulation in any home | The installation standard NZS 4246:2016 |
These overlap less than people expect, and they use different numbers. Mixing them up is the most common source of confusion.
New builds: Building Code clause H1
H1 sets how well a new building holds heat, using six climate zones. It is a different system from the rental rules below, with its own numbers. The edition currently in use is the sixth edition of H1/AS1, effective 27 November 2025. For the full picture, read our guide to the H1 standards or MBIE’s H1/AS1 document.
Your designer or builder decides how the plans meet H1. We install new build insulation at framing stage, to the specification you give us.
Rentals: the Healthy Homes insulation standard
Ceiling and underfloor insulation has been compulsory in all rental homes since 1 July 2019, and the Healthy Homes insulation standard builds on that. MBIE’s Healthy Homes insulation guide sets out the minimum R-values for new or topped-up insulation:
| Zones 1 and 2 | Zone 3 | |
|---|---|---|
| Ceiling | R2.9 | R3.3 |
| Underfloor | R1.3 | R1.3 |
A few other points from the same guide:
- In most situations, existing ceiling insulation needs to be at least 120mm thick.
- Insulation also has to be in reasonable condition. That means no dampness or mould, no rips or tears, no visible gaps, and no settling or compression below 120mm in a ceiling.
- Foil underfloor insulation often does not meet the standard. Retrofitting or repairing foil insulation has been prohibited under the Building Act since 1 July 2016, because of the risk of electric shock.
- Some homes and some areas are exempt, for example where a professional installer cannot reach the space safely.
We go through the details in insulation requirements for rental properties under the Healthy Homes standards.
If you are a landlord, we can help with the insulation your rental needs and arrange a Healthy Homes assessment for you.
Every install: NZS 4246:2016
MBIE’s guide says insulation should be installed according to NZS 4246:2016, the New Zealand Standard for installing bulk thermal insulation. In practice that covers things like keeping the required clearances around downlights and flues, keeping a gap between the insulation and the roof underlay, and fitting the insulation snugly so it is not compressed or left with gaps.
This is why installation quality matters as much as the product. A good batt that is squashed or gappy will not do what its label says.
What these standards do not tell you
The standards set minimums. They do not tell you what is best for your particular home, your budget or the access you have. Some practical things to keep in mind:
- R-values are printed on the packaging. If you want to know what a product does, check the label rather than assuming from thickness alone. Our R-values explainer covers how to read it.
- Old insulation can still be a problem even if it is thick. Dampness, compression and gaps all count against it.
- A minimum is not always the best target. If you are already getting work done, it is worth asking what the next step up would involve.
Getting a clear picture of your own home
Our free consultation and assessment is usually done through our online system, or in person for more complicated homes or if you would prefer it. We look at what you have, what is missing and what the access is like, then send a clear, detailed quote with no hidden fees.
Guide prices are $1,600 to $2,000 for a ceiling and $2,200 to $2,500 for underfloor, for a 100m² home. Your quote depends on access and materials.
Get a free, no-obligation quote and we aim to call you back within 48 hours, or call us on 027 482 0333. You can also see our ceiling insulation and underfloor insulation services.