R-value
R-value is the measure of a material's resistance to heat flow. Higher R = more insulation. Used across NCC 2022 climate zone tables for ceiling, walls, and floors.
Ask Chalkline about this →R-value (thermal resistance) measures how strongly a material resists the flow of heat. The higher the R-value, the better the insulating performance. In Australia, R-values for insulation products are declared in units of m²K/W and must be tested to AS/NZS 4859.1:2018.
The NCC 2022 ABCB Housing Provisions Standard (Part 13.2) uses R-values as the compliance metric for building fabric under the elemental Deemed-to-Satisfy pathway. Required R-values vary by climate zone and building element: ceiling insulation requirements range from R1.5 in zone 1 (tropical north) to R4.5+ in zones 7-8 (alpine). The NatHERS pathway does not prescribe R-values directly; the assessor’s model determines the combination of insulation, glazing, and orientation needed to reach the required star rating.
Key rule: the R-value printed on a product is the declared value at standard thickness and density. Compressing bulk batts during installation reduces the achieved R-value below the declared figure. Batts must be installed at full thickness without compression to meet the declared value (AS 3999:2015).
Also known as: thermal resistance, R value
Category: insulation, energy efficiency
Related
- NCC energy efficiency for residential buildings: Part H6 and the climate zone R-value requirements
- Insulation: where to use it and which type to choose: full climate zone R-value tables and installation rules
See also
- NatHERS: the energy rating scheme that insulation R-values feed into
- Energy report: the NatHERS certificate produced by the assessor
Last updated: 2026-05-09. Verified: 2026-05-09. Quarterly review for currency.