How much does spray foam insulation cost per square foot?

Spray foam insulation is priced per square foot based on foam type and thickness, and the final cost is confirmed after an on-site inspection. The biggest driver is whether you choose open-cell or closed-cell foam and how many inches are needed to reach your target R-value. We often evaluate insulation impacts when sizing HVAC systems and designing airflow in northeast Indiana homes, and we can help you weigh whether tightening ducts or adding insulation delivers better comfort first. A practical reality we see in tight attics: access and prep can outweigh material cost.

Key factors that change the per‑square‑foot price:

• Foam type (open-cell vs closed-cell)
• Required thickness/R-value
• Access and prep (attic, crawlspace, vaulted cavities)
• Existing insulation removal or moisture fixes

Get a written scope that specifies foam type, thickness, and exact areas so quotes are truly comparable. <br/> Updated: 2026-02-11 <br/> Need help in Leo, IN? Call (277) 267 0744 or book online. "Nate provided a thorough discovery of the details around a mini split unit installation, recommendations on room insulation for efficiency, and an on the spot price quote." — Rick S.