cost of spray insulation
1 Open-cell spray foam costs $.40 to $.70 per board foot. 2  Closed-cell spray foam costs $.75 to $1 per board foot. 3  Expressed in terms of square feet, spray foam installation cost is $1.50 to $3.00 per square foot (for an average-sized home between 2,000 to 2,500 square feet, thatâs a total cost of $3,000 to $7,500.pray Foam Insulation Prices. While the function of spray foam insulationâto keep buildings warm during cold weather and cool during warm weatherâis the same as traditional pink fiberglass insulation, thatâs where the similarities between the two materials end.