XPS vs EPS polystyrene foam
XPS Foam EPS Foam There are two types of rigid polystyrene foam plastic insulation, extruded (XPS foam), and expanded (EPS foam). Although both types of insulation are comprised of polystyrene, the two types of manufacturing processes produce finished products with very different performance properties. XPS is manufactured in a continuous extrusion process that produces a homogeneous closed cell crossed section, whereas EPS is manufactured by expanding spherical beads in a mold, using heat and pressure to fuse the beads together. The Expanded Polystyrene Foam industry has put out extensive messaging about how EPS foam performs the same, if not better, than Extruded Polystyrene Rigid Foam Insulation when it comes to R-value and moisture. XPS foam is more moisture-resistant than EPS foam* XPS foam holds R-value better than EPS foam at lower mean temperatures when water is present