The aged R-value refers to the thermal resistance of a roofing material after it has been exposed to the environment and aged over time. The R-value is a measure of a material’s thermal resistance and its ability to resist the transfer of heat through it.

The aged R-value takes into account the impact of environmental factors such as temperature, moisture, and sunlight on the roofing material. These factors can cause changes in the material’s structure and properties, which can affect its thermal performance.

For example, an insulation material with an initial R-value of R-20 may lose some of its thermal resistance over time due to settling, compression, or exposure to moisture. The aged R-value is used to assess the insulation’s thermal performance after these factors have taken effect.

The aged R-value is typically determined through testing, using standards and protocols established by organizations such as ASTM (American Society for Testing and Materials) or ANSI (American National Standards Institute). The test measures the insulation’s thermal resistance after it has been aged in a controlled environment for a specific period of time.

The aged R-value is an important factor to consider when selecting and installing roofing materials, as it can impact the energy efficiency and overall performance of a building. Insulation materials with a higher aged R-value can help to reduce heat loss and improve the energy efficiency of a building, resulting in lower heating and cooling costs over time.