Polystyrene Insulation R Value Per Inch

The connor study test results indicate a rapid drop in r value per inch for eps in the first five years in service with in service r values per inch ranging from 3 13 to 3 70.

Polystyrene insulation r value per inch. The time of testing. It provides r values that range from 3 6 to 4 2 per inch. Expanded polystyrene foam eps is the cheapest and least used foam board product on the market. The conclusions of r value performance are quoted below and shown in figure 1.

Expanded polystyrene eps eps is the insulation used most widely in insulated concrete forms and structural insulated panels sips. Expanded polystyrene insulation is similar to the foam used for packing peanuts and it s typically used for insulated concrete forms also knows as icf s. Eps is suitable for ground contact and can be treated to resist. The thermal conductivity k of a material is expressed as the rate of heat flow in british thermal units per hour.

The r value for foamular xps insulation is provided from testing at two mean temperatures 40ºf and 75ºf and from two aging conditioning techniques 180 day real. For instance if the specified insulation has an r factor of 3 8 and you are using 3 5 inches of insulation the r value is 13 3. Falls in the middle of the three types of rigid foam insulation in both cost and r value used most in walls or below grade applications recyclable and at about r 5 per inch costs around 42 per sq. This product typically has an r value of 3 6 to 4 0 per inch of thickness.

For a 1 in thick 4 8 panel comes unfaced or with a number of different plastic facings. Material costs are about 0 31 per square foot for each inch of thickness plus installation costs. Because rigid foam plastic insulation products are not all aged in accordance with the same standards it is useful to publish comparison r value data. It also is the least expensive.

R value then is the r factor of an insulation material multiplied by the amount of material used. Each type comes with unique advantages. Eps has the lowest average r value of the three most common types of rigid foam insulation around r 4 per inch. Products with a higher r value have a higher cost but have an increased capacity to resist heat flow and therefore provide greater insulation.