'R' Value Comparison Chart

Around most of the world R- values are given in SI Units, typically square metre kelvin per watt. In The US the R- values are given in units of square feet. It is particularly easy to confuse SI and US R - values, because R-values in all countries are often cited without their units eg R-3.5. Usually, however the correct units can be inferred from the context and magnitudes of the values. US R- values are approximately 6  times the SI R- values. For example an R 4.0  fibreglass Pink Batt (ceiling insulation) in Australia would be labeled R- 23 in the USA. This is very important to keep in mind when reading about insulation

To make it easier to compare products we have provided a conversion table below.

To convert Imperial R- values to Metric R-Values multiply by 0.1761

US R- Values Metric R- Values                                              Metric R - Values   US R -Values

1 0.18 1 5.70

2 0.35 2 11.0

3 0.53 3 17.0

4 0.70 4 23.0

5 0.88 5 28.0

6 1.10 6 34.0

7 1.20 7 40.0

8 1.40 8 45.0

9 1.60 9 51.0

10 1.80 10 57.0

11 1.90

12 2.10

13 2.3

14 2.5

15 2.6

16 2.8

17 3.0

18 3.2

19 3.3

20 3.5

21 3.7

22 3.9

23 4.1

24 4.2

25 4.4

26 4.6

27 4.8

28 4.9

29 5.1

30 5.3