Insulation Guides for South Carolina Homes

Spray foam insulation in South Carolina 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. Attic and crawl-space scopes are quoted from measured board feet after an on-site evaluation. 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 South Carolina crawl spaces and moisture-prone areas because it provides a Class II vapor retarder — critical in a hot, humid climate. Open-cell is preferred for many attic applications and costs less per board foot. Our service area sits in IECC Climate Zone 3A); code requires R-38 (Zone 3A min) for attics. Code requires R-38 (Zone 3A min).

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 South Carolina's hot, humid climate, closed-cell foam also resists 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. In South Carolina's cooling-dominated climate, spray foam's dual function as insulation and air barrier stops the humid-air infiltration and radiant heat that fiberglass batts alone cannot address.

Duke Energy and local programs offer rebates for qualifying insulation and air-sealing upgrades; amounts vary by measure and change annually — confirm current amounts 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.