The average cost of blown-in insulation is between $1.65 and $3.80 per square foot. Foam board, or rigid foam board insulation, is best for insulating the exterior of your home and is installed ...

A board foot is 144 cubic inches. With this unit as the standard to go by, open cell spray foam insulation costs between $0.45 and $0.65 per board foot. Closed-cell spray foam is more expensive ...