What is the average R-value of ICF walls?
Walls made of Insulated Concrete Forms are rated on average, like a wood-frame wall constructed with R-25 insulation. But that’s not the whole story. The equivalent R-value performance of ICFs consists of three factors. First is the R-value of the expanded polystyrene. Second, the thermal stability of massive concrete walls reduces the temperature fluctuations and, consequently, the heat load requirements that are common to wood-frame buildings. Finally, air leakage (infiltration) can account for 20 to 40 percent of the heat load requirements of a wood-frame building. ICFs eliminate this air infiltration through the wall assembly. As a result, with the combined performance of the R-value of the expanded polystyrene, the stabilizing effects of the thermal mass of the concrete, and the reduced air infiltration, ICF walls actually perform as high as R-40 to R-50 — or more in some areas of the country.
