Insulation in the UK at least is also rated by R-value (or U-value, where U = 1/R). Can't speak to the rest of Europe. Standard Assessment Producedure (which i

Insulation in the UK at least is also rated by R-value (or U-value, where U = 1/R). Can't speak to the rest of Europe. Standard Assessment Producedure (which is used for household energy ratings) incorporates both this and some fudge factors for draftiness and local wind speed.