Spray Foam vs. Blown-In Insulation: Which Is Better for Florida Homes?

The Key Difference in Florida's Climate

Florida is not a cold-weather insulation problem. It's a heat-and-humidity problem. Your attic in Boynton Beach or Wellington can hit 140°F+ on a summer afternoon. The insulation you choose needs to block radiant heat from above AND resist moisture from the high-humidity air that infiltrates from below.

Both spray foam and blown-in handle this — but in different ways.

Spray Foam Insulation in Florida

Spray foam comes in two types: open-cell and closed-cell. In Florida, closed-cell is the more common choice for attics because it acts as both an air barrier and a vapor barrier.

How it works: A contractor sprays a two-component liquid onto your attic deck (the underside of your roof). It expands, hardens, and creates a seamless seal — no gaps, no cracks, no air movement.

Spray Foam Pros for Florida Homes

• Highest R-value per inch (R-6 to R-7 per inch for closed-cell)
• Creates an airtight seal — eliminates air infiltration completely
• Doubles as a vapor barrier — critical in humid South Florida
• Can be applied to the roofline (conditioned attic) so HVAC equipment in the attic runs in conditioned air
• Longer lifespan — doesn't settle or degrade over time
• Qualifies for FPL rebates in many cases

Spray Foam Cons for Florida Homes

• Higher upfront cost: $1.50–$3.50 per board foot installed (materials and labor)
• A 1,500 sq ft attic job typically runs $3,500–$8,000+ depending on thickness and access
• Requires professional installation — not a DIY project
• If installed improperly, off-ratio foam can cause odor issues
• Harder to inspect for roof leaks later (roof deck is covered)

Blown-In Insulation in Florida

Blown-in insulation (also called loose-fill) is exactly what it sounds like — fiberglass or cellulose material blown into your attic floor through a hose. It fills in around joists, trusses, and existing insulation to bring you up to the recommended R-38 to R-60 for South Florida.

How it works: A contractor uses a blowing machine to fill your attic floor with loose insulation material to a specific depth. It conforms to irregular shapes and fills gaps that batt insulation misses.

Blown-In Pros for Florida Homes

• Lower upfront cost: $1.00–$2.00 per square foot installed
• A 1,500 sq ft attic averages $1,500–$2,500
• Fast installation — most attic jobs completed in one day
• Easy to add more on top of existing insulation
• Fiberglass blown-in doesn't absorb moisture
• Good for attic floor applications (not roofline)
• FPL rebate eligible at qualifying R-values

Blown-In Cons for Florida Homes

• Does NOT air seal — air can still move through the material
• Settles over time — R-value decreases slightly as material compresses
• Doesn't address air infiltration (you need separate air sealing)
• Less effective if your attic has significant air leaks
• Not suitable for the roofline/rafters — only the attic floor

Side-by-Side Comparison

For a deeper look at insulation cost across Palm Beach County, see our pricing guide.

Costs vary significantly based on attic depth, accessibility, and whether removal of existing insulation is required.

What Do Most Palm Beach County Homeowners Choose?

The most common approach for PBC homes built before 2000 is a combination: air seal the attic floor first (foam or caulk around penetrations, wiring, and plumbing), then blow in fiberglass on top of the existing insulation to bring it to R-38 or R-49. This gives you most of the air sealing benefit at a fraction of the spray foam cost.

For newer construction, high-end homes, or homes with attic HVAC units, closed-cell spray foam applied at the roofline is worth the premium — it effectively turns the attic into conditioned space, dramatically reducing the load on your AC system.

How to Decide: Ask These Three Questions

• Is your HVAC equipment in the attic? If yes, spray foam at the roofline is worth considering — it protects your equipment from extreme heat.
• Do you have significant air leaks? If your home is drafty or you see big electric bills in summer, spray foam's air sealing will pay for itself faster.
• What's your budget? If you need a meaningful improvement now and plan to upgrade later, blown-in with air sealing is a smart first step.

Free Estimates for Both Options in Palm Beach County

SunState Insulation connects Boynton Beach, Wellington, Delray Beach, and Palm Beach Gardens homeowners with licensed local contractors who install both spray foam and blown-in insulation. They'll assess your attic, explain what you actually need (not just what's most expensive), and give you a free estimate for both options so you can decide.

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