Insulation Fiberglass batt Blown fiberglass (attic) Mineral (rock) wool Loose-fill cellulose Dense-pack cellulose PET fibre wool EPS rigid board (Type II) XPS rigid board Polyiso board (foil faced) Closed-cell spray polyurethane Open-cell spray polyurethane Thickness (in)

R-value (h·ft²·°F/BTU)

11.20

RSI (m²·K/W)

1.972

U-factor (W/m²·K)

0.507