Insulation is a major concern when considering energy consumption of buildings. Builders today are embracing new technologies and products to reduce energy consumption and maximize returns while maintaining quality standards. Thermal resistance – or the resistance of heat flow through insulation – is crucial to achieving reduced energy consumption in building designs. Thermal resistance is commonly referred to as R-value. The higher the R-value, the greater the insulating power of an insulation. EPS insulation has found numerous application areas across a wide range of industries due to its light weight and rigidity, as well as its thermal resistance properties. While the trapped gases in the cells of Polysio and XPS foam may provide an initial high R-value, these products have been found to lose R-value over their lifetime. Unlike Polyiso and XPS, EPS provides a permanent lifetime R-value and does not lose R-value over time. The five year and 50 year R-values for EPS are the same as the initial R-value since the gas trapped in the cells of EPS is atmospheric air. This is one reason the National Institute of Standards & Technology (NIST) chose EPS as the Standard Reference Material for Thermal Conductivity (SRM 1453), using a lot of samples certified in 1996 that still provide the same R-value today. To learn more about long-term thermal resistance and R-value performance, refer to this EPS Technical Bulletin.