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Spray foam insulation in Michigan typically costs $1.00–$1.60 per board foot for open-cell foam and $1.60–$2.60 per board foot for closed-cell foam. A typical attic runs $1,800–$4,500 for a typical 1,200 sq ft attic; rim joist projects average $1,200–$2,500. Final pricing depends on access, required thickness, and any removal of existing insulation.

Closed-cell spray foam delivers approximately R-6 to R-7 per inch; open-cell approximately R-3.5 to R-4 per inch. Closed-cell is recommended for Michigan basements, crawl spaces, and rim joists because it provides a Class II vapor retarder — critical in cold, humid winters. Open-cell is preferred for many attic applications and costs less per board foot. Our service area sits in IECC Climate Zone 5A; northern Lower Michigan and the Upper Peninsula are Zones 6A and 7. Code requires R-49 minimum attic insulation under Michigan's residential energy code (IECC Zone 5A).

Spray foam is a permanent insulation with an expected lifespan of 80+ years without sagging or compressing when properly installed. Unlike fiberglass batts, it does not compress, sag, or absorb moisture. In Michigan's freeze-thaw climate, closed-cell foam also adds rigidity to walls and rim joists and prevents the moisture infiltration that shortens the life of other insulation types.

Homeowners typically see 20–40% lower heating and cooling costs after air sealing and insulation, depending on the home's starting condition. Most of Lower Michigan logs roughly 6,200 to 6,900 heating degree days per year. Spray foam's dual function as insulation and air barrier eliminates the convective heat loss that fiberglass batts alone cannot address.

DTE Energy and Consumers Energy offer rebates for qualifying insulation and air-sealing upgrades through their Home Energy Efficiency programs. Amounts vary by measure and change annually — confirm current amounts at dte.com or consumersenergy.com before your estimate. The federal 25C Energy Efficient Home Improvement Credit ended December 31, 2025. No federal tax credit currently applies to insulation work; utility rebates remain available.