More Insulation & Weatherproofing: Attic Insulation ·Blown In Insulation ·Basement Waterproofing ·Window Replacement
Spray foam is the premium insulation choice — it expands to fill and seal every gap, insulating and air-sealing in a single step. It costs $1.50 to $5 per square foot installed in 2026, or about $1,500–$6,000 per project, with the foam type driving the price.
What you’re paying for
The cost is mostly the foam and skilled application, plus prep (masking and protecting the space) and any old-insulation removal. Spray foam is equipment- and labor-intensive, which is why it costs more per square foot than batt or blown-in.
Open-cell vs. closed-cell
This is the key decision. Open-cell ($1.50–$3.50/sq ft) is softer and vapor-permeable, with an R-value around 3.5–3.7 per inch — good for interior walls and sound dampening. Closed-cell ($3–$5/sq ft) is rigid, with R-5 to R-7 per inch, and doubles as an air and moisture barrier — the choice for rim joists, basements, and tight spaces where you need maximum R-value per inch.
When spray foam is worth it
Spray foam’s advantage is sealing. In leaky, irregular, or hard-to-reach areas — rooflines, rim joists, cathedral ceilings — it outperforms batt and blown-in by air-sealing as it insulates. For a simple, accessible attic floor, blown-in insulation delivers most of the benefit for far less.
How to save on spray foam
- Use closed-cell only where you need it (rim joists, moisture-prone areas) and cheaper insulation elsewhere.
- Get multiple quotes — application pricing varies widely.
- DIY rim-joist kits for small sealing jobs.
- Right-size the thickness to your target R-value rather than over-applying.
| Item | Typical range | Notes |
|---|---|---|
| Open-cell foam | $1.50 – $3.50 / sq ft | – |
| Closed-cell foam | $3.00 – $5.00 / sq ft | – |
| Prep & masking | $200 – $1,000 | – |
| Old insulation removal | $1 – $1.50 / sq ft | – |
| Option | Typical range | Notes |
|---|---|---|
| Open-cell | $1.50 – $3.50 / sq ft | R-3.5–3.7 per inch; softer, vapor-permeable |
| Closed-cell | $3.00 – $5.00 / sq ft | R-5–7 per inch; rigid, air & moisture barrier |
| Rim joists / small areas | $2 – $6 / sq ft | Higher per-sq-ft for small jobs |
What affects the price
- Open-cell vs. closed-cell Closed-cell has higher R-value per inch and blocks moisture, but costs more than open-cell.
- Thickness / R-value More inches of foam mean more material and higher cost.
- Area & access Larger, open areas are cheaper per square foot than tight or detailed spaces.
- Prep Masking, removing old insulation, and protecting the space add cost.
Spray foam insulation cost by state
Where you live can change the price as much as the options you pick. Labor is a big part of the bill, and construction workers are paid more in some states than others. A typical spray foam insulation job costs about $1.75 to $5.85 per sq ft in Hawaii (17% above the U.S. average). In Arkansas, it costs about $1.30 to $4.25 per sq ft (15% below the U.S. average).
See the typical cost in all 50 states and D.C.
| State | Typical range |
|---|---|
| Alabama | $1.30 – $4.35/sq ft |
| Alaska | $1.75 – $5.75/sq ft |
| Arizona | $1.40 – $4.75/sq ft |
| Arkansas | $1.30 – $4.25/sq ft |
| California | $1.70 – $5.60/sq ft |
| Colorado | $1.50 – $5/sq ft |
| Connecticut | $1.60 – $5.35/sq ft |
| Delaware | $1.45 – $4.90/sq ft |
| District of Columbia | $1.60 – $5.40/sq ft |
| Florida | $1.35 – $4.55/sq ft |
| Georgia | $1.40 – $4.60/sq ft |
| Hawaii | $1.75 – $5.85/sq ft |
| Idaho | $1.40 – $4.70/sq ft |
| Illinois | $1.75 – $5.75/sq ft |
| Indiana | $1.50 – $5.05/sq ft |
| Iowa | $1.45 – $4.85/sq ft |
| Kansas | $1.40 – $4.75/sq ft |
| Kentucky | $1.40 – $4.65/sq ft |
| Louisiana | $1.35 – $4.50/sq ft |
| Maine | $1.45 – $4.90/sq ft |
| Maryland | $1.50 – $5/sq ft |
| Massachusetts | $1.75 – $5.75/sq ft |
| Michigan | $1.50 – $5/sq ft |
| Minnesota | $1.65 – $5.45/sq ft |
| Mississippi | $1.30 – $4.35/sq ft |
| Missouri | $1.55 – $5.10/sq ft |
| Montana | $1.45 – $4.90/sq ft |
| Nebraska | $1.40 – $4.70/sq ft |
| Nevada | $1.55 – $5.15/sq ft |
| New Hampshire | $1.50 – $4.95/sq ft |
| New Jersey | $1.70 – $5.70/sq ft |
| New Mexico | $1.40 – $4.60/sq ft |
| New York | $1.65 – $5.50/sq ft |
| North Carolina | $1.35 – $4.50/sq ft |
| North Dakota | $1.50 – $5.05/sq ft |
| Ohio | $1.50 – $5/sq ft |
| Oklahoma | $1.35 – $4.55/sq ft |
| Oregon | $1.65 – $5.50/sq ft |
| Pennsylvania | $1.50 – $5.05/sq ft |
| Rhode Island | $1.55 – $5.20/sq ft |
| South Carolina | $1.35 – $4.55/sq ft |
| South Dakota | $1.35 – $4.50/sq ft |
| Tennessee | $1.40 – $4.60/sq ft |
| Texas | $1.35 – $4.55/sq ft |
| Utah | $1.40 – $4.70/sq ft |
| Vermont | $1.45 – $4.85/sq ft |
| Virginia | $1.40 – $4.75/sq ft |
| Washington | $1.75 – $5.80/sq ft |
| West Virginia | $1.40 – $4.75/sq ft |
| Wisconsin | $1.55 – $5.20/sq ft |
| Wyoming | $1.50 – $4.95/sq ft |
These are numbers to plan with, not quotes. Each one is this guide's U.S. range, adjusted for what construction workers earn in that state. See every state cost guide or how we estimate.
Common questions
- How much does spray foam insulation cost?
- Open-cell runs $1.50–$3.50 per square foot installed and closed-cell $3–$5. A typical project is $1,500–$6,000, averaging around $3,500.
- Open-cell vs. closed-cell — which should I use?
- Open-cell is cheaper and good for interior walls and sound dampening. Closed-cell has nearly double the R-value per inch and acts as an air and moisture barrier — better for rim joists, basements, and where space is limited.
- Is spray foam worth the higher cost?
- Its edge is that it air-seals and insulates in one application, so it outperforms batt/blown-in in leaky or irregular spaces. For a simple, accessible attic floor, blown-in is more cost-effective.
- Can I DIY spray foam?
- Small DIY kits exist for rim joists and gaps, but whole-area spray foam needs professional equipment and careful application — improper installation can off-gas or fail to cure.
- Does spray foam add home value?
- Energy-efficiency upgrades help a home's comfort and operating cost, which can aid resale, though the direct return varies. The bigger payoff is lower bills.
- Does spray foam off-gas?
- Properly installed foam cures and is inert. Off-gassing concerns come from improper mixing or installation, which is why professional application matters.
How we estimate: These are typical U.S. prices for materials and for hiring a pro to install them. We checked them against the 2026 sources listed below (see how we get our numbers). Your price depends on where you live, the size of the job and the materials you pick. Get two or three written bids before you choose a contractor.
Sources
We checked the prices on this page against 2026 numbers from these sources: