Florida Blown-In Insulation Guide: R-Values, Costs & Climate Strategy

Florida's climate puts unique demands on attic insulation. Between intense solar gain, months of high humidity, and coastal salt air, a properly engineered attic is one of the highest-ROI upgrades a homeowner can make. This guide explains the essentials of blown-in insulation in Florida so you can make an informed decision.

R-Value Targets

Florida code calls for attic insulation between R-30 and R-49, with R-38 the practical target for most South Florida homes. Blown-in fiberglass is the most common choice because it fills around wiring and ductwork without leaving the gaps that batt insulation creates.

Material Comparison

Blown-in fiberglass is non-combustible, moisture-resistant, and retains its R-value over time. Cellulose settles and can absorb humidity. Closed-cell spray foam seals air leaks but is far more expensive and can trap moisture against the roof deck if ventilation isn't addressed.

Cost

Installed blown-in fiberglass typically runs $1.50–$3.50 per square foot. A 2,000 sq ft home usually lands between $3,000 and $5,000, and most homeowners recover the cost in 3–5 years through lower cooling bills.

Climate Strategy

In Florida, insulation alone isn't enough. Pair it with attic air sealing, balanced ridge-and-soffit ventilation, and — for two-story or larger homes — a radiant barrier. Coastal homes should also evaluate moisture and mold remediation before adding new material.