What is the R-value?

What is the R-value?

In each climate zone, the Building Code of Australia has determined a minimum amount of needed insulation expressed in R-value (the efficiency of a material at stopping heat flow through it.)

This is the Building Code’s recommended amount of insulation, in R-values, for each climate zone and insulation type:

Climate Zone

1

2

3

4

5

6

7

8

Ceiling insulation for homes with very light coloured roofs

R4.1

R4.1

R4.1

R4.1

R4.1

R4.1

R4.1

R6.3

Ceiling insulation for homes with light coloured roofs

R4.6

R4.6

R4.6

R4.6

R4.6

R4.6

R4.6

R6.3

Ceiling insulation for homes with dark coloured roofs

R5.1

R5.1

R5.1

R5.1

R5.1

R5.1

R5.1

R6.3

Wall insulation

R2.8

R2.8

R2.8

R2.8

R2.8

R2.8

R2.8

R3.8

Underfloor insulation

R1.5

R1.0

R2.25

R1.0

R2.25

R2.25

R2.75

R3.25


R4.1 is about 20 cm thick (depending on the material and its density).

When checking the R-value of a certain insulate type, find its effective or installed R-value. Due to various building and external conditions, this may differ from its labelled R-value.
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