Business and Professions Code section 19020


“R-value” means a measure of thermal resistance of material or composite materials. “R-value” is equal to the reciprocal of the conductance of a given material, or
R-value =
1
conductance of the material
where the conductance of the material is: Btu (hour × square foot × Fahrenheit degree average temperature difference between two surfaces).
Last Updated

Apr. 24, 2025

§ 19020’s source at ca​.gov