Spray foam insulation costs $1,455 to $4,338 in 2026
The average project is about $2,889. Installed, open cell foam runs about $1 to $3.50 per square foot and closed cell $1.50 to $5. A small rim joist job can be $670. A whole home can reach $8,000. Most companies have a minimum of $1,000 to $2,000.
Cost by foam type and job
| Open cell, per board foot | $0.60 to $1.60 installed according to Angi. Other 2026 guides list $0.35 to $0.65. |
|---|---|
| Closed cell, per board foot | $1.30 to $3.10 installed according to Angi. Other guides list $1.00 to $2.50. |
| Open cell, per square foot at full depth | $1.00 to $3.50. |
| Closed cell, per square foot at full depth | $1.50 to $5.00. Roof decks in humid coastal areas reach $4 to $7. |
| 1,000 square foot attic roof deck | $3,000 to $5,000 in open cell. $4,500 to $7,000 in closed cell. |
| 1,500 square foot attic | $3,000 to $7,500. |
| Whole home | Up to $8,000. One guide puts larger projects around $6,000. |
| Removing old insulation first | $1 to $2 per square foot. |
| Mold remediation, if found | $1,125 to $3,345. |
What pushes a quote up
| Open or closed cell | Closed cell costs two to three times more per board foot. It is denser, R-6 to R-7 per inch against about R-3.7, and it blocks moisture. |
|---|---|
| Thickness | Each inch of closed cell adds about $1.75 to $3.50 per square foot. Going from R-13 at 2 inches to R-26 at 4 inches doubles the material. |
| Where it goes | Open wall cavities in new work are cheapest. Roof decks cost more because the work is overhead. Cathedral ceilings and tight crawl spaces cost the most. |
| Minimum job fee | $1,000 to $2,000. A spray rig costs $80,000 to $150,000, and the crew has to cover the trip. |
| Your region | Northeast and West Coast markets run 10 to 20 percent higher. |
Spray foam insulation cost by region
| Lower cost states | $1,175 to $3,500. Alabama, Arkansas, Indiana, Iowa, Kansas, Kentucky, Mississippi, Missouri, Oklahoma, Tennessee, West Virginia and most rural areas. |
|---|---|
| Average cost states | $1,455 to $4,338. Arizona, Florida, Georgia, Michigan, North Carolina, Ohio, Pennsylvania, Texas, Virginia and most mid size cities. |
| Higher cost states | $1,900 to $5,600. California, Connecticut, Hawaii, Massachusetts, New Jersey, New York, Washington, plus big metros such as Chicago, Denver and Washington DC. |
These rows are our estimate. We took the typical national range and adjusted it for local labor costs, which run about 20 percent lower in the cheapest states and about 30 percent higher in the dearest ones. Humid coastal areas lean toward closed cell foam for its moisture barrier, which pushes local averages up.
Board foot or square foot: the unit that makes quotes impossible to compare
A board foot is one square foot of foam, one inch thick. A square foot price is that same square foot at whatever depth the contractor plans to spray. So $1.50 per board foot and $4.50 per square foot can be the exact same quote, if the foam is 3 inches deep. This is the top reason people think one company is three times the price of another.
To compare two quotes, turn both into total dollars for the same area at the same R-value. Closed cell foam gives about R-6.5 per inch, so R-20 needs about 3 inches. Open cell gives about R-3.7 per inch, so the same R-20 needs more than 5 inches. Ask each company for the inches, the R-value and the total.
Why the guides disagree on the board foot price
Angi lists open cell at $0.60 to $1.60 per board foot and closed cell at $1.30 to $3.10. Modernize lists $0.40 to $0.65 and $1.00 to $1.50. The lower numbers are closer to a material price. The higher ones are fully installed prices with labor, the rig and cleanup. Both are called price per board foot.
When foam is worth it, and when it is not
One 2026 insulation guide is direct. For rim joists, crawl spaces, basements and attics that hold ductwork, spray foam does three jobs in one pass: it insulates, it air seals and it blocks vapor. For an open attic floor with room to pile insulation deep, blown in reaches R-49 to R-60 for 40 to 70 percent less. Foam costs 2 to 5 times more than blown in for the same area.
Why this costs more in 2026
Spray foam is made from petroleum based chemicals, so it follows the oil price more closely than fiberglass or cellulose does.
Fuel is the common thread. AAA's national average for diesel passed $6 a gallon for the first time on September 11, 2026, up from about $3.70 a year earlier (CBS 8 reporting AAA). Every truck roll and every delivery carries that. Materials moved too. Associated Builders and Contractors reported construction input prices up 4.8 percent in a year as of March 2026, the largest annual gain since January 2023, and the Associated General Contractors said diesel jumped 37.8 percent in one month, the largest one month rise since 1990 (Roofing Contractor, April 2026). Some suppliers added freight surcharges this year. Ask how long your quote is good for.
How to judge the quote in your hand
- Get inches and R-value in writing. A price per square foot means nothing without the depth.
- Check the foam type on every line. Open and closed cell are not interchangeable, and some quotes mix them.
- Ask about the minimum. Small jobs often hit the $1,000 to $2,000 floor no matter the area.
- Ask how long to stay out. Foam gives off fumes while it cures. The crew should give you a re entry time.
- Ask about removal. Old insulation has to come out first in many attics, at $1 to $2 per square foot.
Ways to pay less
- Use foam only where it earns its price. Rim joists, crawl spaces and roof decks with ducts. Use blown in on the open attic floor.
- Choose open cell inside. For interior walls and dry attics it costs about half as much as closed cell.
- Combine areas in one visit. One trip spreads the minimum fee across more square feet.
- Skip the kit for big areas. DIY kits cost $0.75 to $2.00 per square foot in materials and are hard to apply evenly.
What will this cost me?
Pick the job, your state's cost level and the last detail. The estimate updates as you change them.
An estimate built from published 2026 cost guides. It is not a quote. Get a written quote before work starts.
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Book a free 15 minute callNo pitch deck. We run your audit live on the call.Common questions
How much does spray foam insulation cost?
$1,455 to $4,338 for most projects in 2026, with an average of $2,889. Installed prices run $1 to $4.50 per square foot depending on foam type and depth.
What is a board foot of spray foam?
One square foot of foam, one inch thick. A quote per square foot includes the full depth, so it looks much higher than a quote per board foot.
Is closed cell or open cell cheaper?
Open cell. Closed cell costs two to three times more per board foot, but it has a higher R-value per inch and blocks moisture.
How much does it cost to spray foam a 1,000 square foot attic?
$3,000 to $5,000 in open cell and $4,500 to $7,000 in closed cell for a roof deck.
Is spray foam worth the cost?
For rim joists, crawl spaces and attics with ductwork, yes. For an open attic floor, blown in gives the same R-value for 40 to 70 percent less.