What is the R-value of extruded polystyrene?

Extruded polystyrene (XPS) has an R-value that typically falls within the range of R5 to R7 per inch of thickness, depending on the density and manufacturing process. The answer indicating R5 is commonly accepted as a standard value for XPS insulation. This level of thermal resistance makes it an effective insulator for various applications in construction, including walls, roofs, and foundations.

Understanding this R-value is crucial for architects and builders as they design energy-efficient buildings. The choice of insulation materials can significantly impact the overall thermal performance of a building, influencing energy consumption and occupant comfort. In this context, R5 is a realistic representation of the insulating capabilities of extruded polystyrene, making it a popular choice among insulation materials.

The values listed in the other options, while they indicate R-values, do not accurately reflect the typical performance of extruded polystyrene.