Spray Foam vs. Blown-In Insulation: Which Wins in Central Florida?

Choosing between spray foam and blown-in insulation is the single biggest efficiency decision Central Florida homeowners make. Both stop heat transfer, but they behave very differently in our hot, humid climate. Here's how they compare on R-value, cost, moisture control, and long-term performance.

R-Value: Spray Foam Wins per Inch

Closed-cell spray foam offers the highest R-value per inch of any commercially available insulation — up to R-7. In a 2×4 wall cavity that means roughly R-21 of thermal resistance, versus R-13 to R-15 with blown-in fiberglass or cellulose. For low-clearance attics and cathedral ceilings, spray foam packs more performance into less space.

Air Sealing: The Florida Difference

In Central Florida, air infiltration drives most cooling loss. Spray foam expands to seal every crack, gap, and penetration — creating a continuous air barrier. Blown-in insulation slows heat but lets conditioned air escape through the same cracks. That's why we recommend spray foam for attic decks and rim joists in humid climates.

Cost: Blown-In Is Cheaper Up Front

Blown-in insulation costs a fraction of spray foam per square foot, making it the go-to choice for topping up existing attic insulation on a budget. Spray foam costs more but typically pays back through 20–40% lower energy bills within 3–7 years in Florida homes.

Which Should You Choose?

• Choose spray foam for new construction, whole-home retrofits, encapsulated attics, and moisture-prone walls.
• Choose blown-in to top up an existing attic where the vapor barrier and air sealing are already in place.
• Avoid blown-in in vented attics with heavy humidity or in walls with known air-leak issues.