Phenolic insulation is known for having one of the highest R-values among insulation materials. The R-value measures the material’s thermal resistance, indicating how effectively it resists heat transfer. Phenolic insulation, particularly the Kooltherm range, boasts an R-value rating between R-5 to R-8+, while PIR boards have an R-value of around R-4.5.

The exceptional thermal performance of phenolic insulation is attributed to its fine cell structure and high closed cell content. This means that if you require highly efficient thermal insulation for your building, using phenolic foam insulation is an excellent choice.