XENERGY: a new generation extruded polystyrene from the inventor of STYROFOAM. XENERGY XPS combines the proven features of STYROFOAM XPS - durability, reliability and strength with improved insulation performance and a Global Warming Potential (GWP) of less than five. The first XENERGY XPS product available in NZ is XENERGY SL designed for inverted roof insulation but is also used under concrete slab for it's high compression strength. XENERGY SL offers 4mW thermal conductivity gains in 140mm, 160mm, 180mm and 200mm thicknesses, an 11% improved insulation performance compared with ROOFMATE SL-A.