XO/UF superior performance PIR offers excellent insulation performance with a thermal conductivity of 0.021 W/mK. The floor in any building is an area of considerable downward heat loss when not properly insulated. XO/UF will significantly improve the U-Value of new and existing floors. XO/UF is lightweight, easy to install and combines high compressive strength with low thermal conductivity, providing a high performance solution for floor insulation.