Polystyrene Insulation R Value Per Inch

Eps has the lowest average r value of the three most common types of rigid foam insulation around r 4 per inch.

Polystyrene insulation r value per inch.

For a 1 in thick 4 8 panel comes unfaced or with a number of different plastic facings. 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. 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. This product typically has an r value of 3 6 to 4 0 per inch of thickness.

Material costs are about 0 31 per square foot for each inch of thickness plus installation costs. R value then is the r factor of an insulation material multiplied by the amount of material used. The thermal conductivity k of a material is expressed as the rate of heat flow in british thermal units per hour. It also is the least expensive.

Products with a higher r value have a higher cost but have an increased capacity to resist heat flow and therefore provide greater insulation. The conclusions of r value performance are quoted below and shown in figure 1. Also called styrofoam insulation this is the least expensive material. 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.

Expanded polystyrene foam eps is the cheapest and least used foam board product on the market. Additional r value for a masonry wall constructed using these materials needs to add the insulating value of additional wall components typically included such as 1 solid foam polyisocyanurate r 8 extruded polystyrene r 5 expanded polystyrene r 4 or 1 of perlite r 2 7 and for an exterior air film winter no wind r 0 17 an interior. Expanded polystyrene made from expanded foam beads that are molded into shape expanded polystyrene or eps is ideal for above grade applications such as exterior walls and offers an r value of 3 6 to 4 2 per inch. 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.

Each type comes with unique advantages. 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. It provides r values that range from 3 6 to 4 2 per inch. The time of testing.