NZ & Australia  |  Healthy Homes & NCC  |  Free Tool

Insulation
R-Value Calculator

Find the minimum and recommended R-value for ceiling, underfloor, and wall insulation in your NZ or Australian climate zone. Covers Healthy Homes Standards and NCC requirements.

Free. No signup required.

R2.9–R9.8
NZ ceiling R-value range by zone
R3.2–R9.0
AU NCC ceiling R-value range by zone
30%
Typical heat loss reduction with good insulation

Calculate Required R-Value

Select your country, climate zone, and area type to find the required and recommended R-value.

Your Location

NZ Healthy Homes Standards zones. Also used for H1 Building Code compliance.

Insulation Details

0 = no insulation. Check your product label or existing work records.

NZ Insulation Requirements by Zone

Healthy Homes minimum vs. recommended R-values for ceiling insulation.

ZoneHHS MinimumH1 (new build)
Zone 1–3 (Northland to Nelson)R2.9R6.6
Zone 4–5 (Wellington, Canterbury)R3.3R6.6
Zone 6 (Otago, Southland)R3.6R9.8

HHS = Healthy Homes Standard (existing rental properties). H1 = NZ Building Code Energy Efficiency (new builds / significant alterations).

Insulation Tips

Ceiling insulation delivers the largest heat saving for the investment in most NZ homes
Check the installed R-value on the product label — not all batts are the same
Underfloor insulation must be correctly supported — sagging batts lose R-value
Wall insulation is most economical when installed during a renovation or re-cladding
Combining insulation with draught-stopping and double glazing multiplies the benefit
A licensed insulation installer can certify Healthy Homes compliance for landlords

Frequently Asked Questions

What R-value do I need for ceiling insulation in NZ?

Healthy Homes Standard minimum is R2.9–R3.6 depending on your zone. For new builds under H1, the requirement is R6.6 (R9.8 in Zone 6). The calculator above gives the exact figure for your zone.

Do rental properties need ceiling insulation in NZ?

Yes. The NZ Healthy Homes Standards require ceiling insulation to meet minimum R-values for most rental properties. Compliance is required within 90 days of a new tenancy beginning.

What's the difference between R-value and thickness?

R-value measures thermal resistance — not thickness. Different materials (wool, fibreglass, polyester, rigid foam) give different R-values at the same thickness. Always check the installed R-value on the product label.

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