How much does 1500 sq ft of insulation cost?

The cost to insulate 1500 square feet depends heavily on the type of insulation, whether it is new construction or retrofit, and if you do it yourself or hire a contractor. For attic insulation, which is the most common 1500 square foot job, DIY blown-in fiberglass or cellulose costs about $0.60 to $1.20 per square foot for materials to reach R38 to R49. So 1500 square feet would cost $900 to $1800 in materials if you use the free blower rental from Home Depot or Lowe's. Hiring a contractor to blow in insulation for 1500 square feet typically costs $1.50 to $3.00 per square foot, or $2250 to $4500 total including labor, air sealing, and cleanup. For wall insulation in a 1500 square foot home, the wall area is about 3500 to 4000 square feet, not 1500. Dense-pack cellulose or Spider fiberglass blown into existing closed walls costs $2.00 to $4.00 per square foot of wall area, or $7000 to $16000 for a whole house. For batts in new construction, R13 batts for 1500 square feet of wall area cost $750 to $1200 in materials. Spray foam is the most expensive. Open-cell spray foam for 1500 square feet of attic floor costs $3.50 to $5.50 per square foot, or $5250 to $8250, while closed-cell costs $5.50 to $8.50 per square foot, or $8250 to $12750. Utility rebates can reduce these costs by $300 to $1000.