How much does spray foam insulation cost?
Spray foam insulation cost in 2026 runs roughly $1–$5 per square foot depending on type and thickness, according to industry cost data from sources like HomeGuide and Angi, with a typical attic project landing near $2,000–$6,000. Closed-cell foam costs more than open-cell. Spray foam costs more than traditional blown-in insulation, but it does something blown-in doesn't: it insulates and air-seals at the same time — which in Florida's humid, leaky-attic reality can deliver bigger comfort and efficiency gains than R-value alone.
Key takeaways
- Spray foam runs about $1–$5 per square foot; a typical attic project is $2,000–$6,000.
- Open-cell is cheaper and a good air-sealer; closed-cell is denser, resists moisture, costs more.
- Spray foam insulates and air-seals together — stopping the humid-air leaks that drive Florida cooling bills.
- Attic encapsulation (foam on the roof deck) helps when ducts run through the attic.
- It costs more than blown-in, so weigh the upgrade against your goals and budget.
Table of contents
- What spray foam costs
- Open-cell vs. closed-cell
- Why air-sealing matters in Florida
- Attic encapsulation explained
- Spray foam vs. blown-in
- Where to start
- FAQ
What spray foam costs
Spray foam is priced per square foot (or per board foot, which factors in thickness), and the type drives most of the range. Here's the 2026 picture from HomeGuide's spray foam cost data:
| Type / project | Typical cost | Notes |
|---|---|---|
| Open-cell (per sq ft) | ~$1–$3 | Lighter, cheaper, good air-seal |
| Closed-cell (per sq ft) | ~$2–$5 | Denser, moisture barrier, more R per inch |
| Typical attic project | ~$2,000–$6,000 | Varies with size and type |
| Attic encapsulation | higher | Roof-deck application, conditioned attic |
A worked example: open-cell foam in a standard Orlando attic might land in the low-to-mid four figures, while closed-cell encapsulation of the roof deck on the same home runs higher. The thickness needed to hit a target R-value also affects cost, so get the type, coverage, and resulting R-value spelled out.
Open-cell vs. closed-cell
The two types behave differently, and the right one depends on the job. Open-cell foam is lighter and softer, expands more, and costs less. It's an excellent air-sealer and works well for interior walls and many attic applications — its main limits are lower R-value per inch and less moisture resistance.
Closed-cell foam is dense and rigid, with a higher R-value per inch, a built-in moisture barrier, and even some added structural rigidity — a meaningful plus in a hurricane-prone state. It costs more, but in spots where moisture resistance or maximum insulation in limited space matters, it earns the premium. Many Florida projects use closed-cell where moisture and storm resistance count, and open-cell where cost-effective air-sealing is the goal. A good contractor recommends based on the specific application, not a one-size pitch.
Why air-sealing matters in Florida
Here's what sets spray foam apart in this climate. Traditional insulation slows heat transfer but doesn't stop air leakage — and a leaky building envelope lets hot, humid Florida air infiltrate all day, which your AC then has to cool and dehumidify. Spray foam seals those leaks as it insulates, cutting that infiltration at the source.
The payoff is comfort and efficiency: less humid air sneaking in means a more even temperature, lower humidity, and an AC that runs less during our long cooling season. It also reduces the moisture infiltration that feeds mold. This is why spray foam can outperform its R-value on paper in Florida — the air-sealing is doing work that a same-R blanket of blown-in doesn't. The U.S. Department of Energy's insulation guidance and ENERGY STAR's seal-and-insulate program both frame air-sealing as a top-tier efficiency move.
Attic encapsulation explained
A common Florida use of spray foam is attic encapsulation — applying foam to the underside of the roof deck rather than the attic floor, which brings the attic into the home's conditioned envelope instead of leaving it a blazing-hot vented space. This matters here for a specific reason: many Florida homes run their AC ducts and air handler through the attic. In a 130-degree vented attic, those ducts lose cooling and sweat; in an encapsulated, semi-conditioned attic, they work far more efficiently.
Encapsulation costs more than insulating the attic floor and changes how the attic is ventilated, so it needs a contractor who understands the building science. But for a home with attic ductwork, it can be one of the more impactful efficiency upgrades — and it pairs with the load reduction from a right-sized AC system.
Spray foam vs. blown-in
The honest comparison: blown-in fiberglass or cellulose is much cheaper and effective at adding R-value to an attic floor — for many homes, topping up attic insulation with blown-in is the best value upgrade. Spray foam costs more but adds air-sealing and, in closed-cell form, moisture and structural benefits that blown-in can't match.
So the choice comes down to goals and budget. If you mainly need more R-value over the ceiling, blown-in wins on cost. If you want to seal a leaky envelope, condition the attic for ductwork, or add moisture and storm resistance, spray foam justifies its premium. Get quotes for both approaches and weigh the upgrade against what you're trying to fix.
Where to start
Start by identifying your goal — more R-value, air-sealing a leaky home, or conditioning an attic with ductwork — since that points to the right product. Because spray foam ties directly to cooling performance, our HVAC directory and Orlando city page are good starting points, with more across the full directory. Get the type, coverage, and resulting R-value in writing, ask whether closed-cell suits your moisture and storm concerns, and compare it against a blown-in attic insulation quote before deciding.
FAQ
How much does spray foam insulation cost in 2026? Industry cost data puts spray foam around $1–$5 per square foot depending on type and thickness, with a typical attic project landing near $2,000–$6,000. Closed-cell foam costs more than open-cell.
What's the difference between open-cell and closed-cell spray foam? Open-cell is softer, cheaper, and a good air-sealer for interior spaces. Closed-cell is denser, more expensive, adds a moisture barrier and structural rigidity, and gives more insulation per inch — useful for Florida's humidity and storm exposure.
Is spray foam worth it in Florida? It can be. Spray foam insulates and air-seals at once, stopping the humid-air leaks that drive cooling costs and moisture problems here. It costs more than blown-in but can deliver bigger comfort and efficiency gains, especially with attic encapsulation.
What is attic encapsulation? Applying spray foam to the underside of the roof deck instead of the attic floor, bringing the attic into the conditioned space. It helps when AC ducts run through the attic, which is common in Florida homes.
Does spray foam help with humidity in Florida? Yes. By air-sealing, it reduces the infiltration of hot, humid outside air that the AC otherwise has to dehumidify. Closed-cell foam also resists moisture, which helps in our climate.