This r-value insulation reference table shows the r-value for a range of material thickness values, assuming a thermal conductivity (k) of 0.04 W/m·K. Every figure is computed with the same engine that powers our R-Value Insulation Calculator, so the numbers are exact.
| Material thickness | R-value |
|---|---|
| 0.025 m | 0.6250 |
| 0.05 m | 1.2500 |
| 0.075 m | 1.8750 |
| 0.1 m | 2.5000 |
| 0.15 m | 3.7500 |
| 0.2 m | 5.0000 |
| 0.3 m | 7.5000 |
| 0.5 m | 12.5000 |
| 0.7 m | 17.5000 |
| 1 m | 25.0000 |
How to use this table
Find the row closest to your material thickness and read across to the r-value. For a value between two rows, the real figure sits between them — or enter your exact numbers in the R-Value Insulation Calculator for a precise answer.
Need a value that is not in the table? — the R-Value Insulation Calculator does it instantly, for free, with the formula and a worked example built in.
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