What is R-Value?
“R” stands for resistance to heat flow or Thermal Resistance Value (TRV), it measures how effectively a material slows the flow of heat from a warmer to a colder area. The higher the R-value, the greater the insulating effectiveness. How is it derived? Simple
R Value = thickness of insulating material ÷ thermal conductivity of material.
R-value is measured through a series of industry standard tests and ethical manufacturers have their values certified by SABS. With the passing of SANS 10400-XA all insulation products must state the R-value of the product on the packaging.
See R-value Chart & Legislation or R-values