What is the difference between open-cell and closed-cell spray foam?

Open-cell is softer, cheaper, and a good air sealer with a lower R-value per inch, suited to interior walls and attics. Closed-cell is denser, costs more, has a higher R-value per inch, and adds a moisture and air barrier, which is why it is used in basements, rim joists, and tight spaces.

Is spray foam worth the extra cost over fiberglass?

Sometimes. Spray foam air-seals and insulates in one step, which can cut energy bills and help in humid or hard-to-seal areas. For a simple, accessible attic, blown-in cellulose or fiberglass often delivers most of the benefit for far less money. Match the product to the problem.

What moves the price of a spray foam job?

Square footage and target thickness, open-cell versus closed-cell, how hard the area is to reach, prep and removal of old insulation, and regional labor rates. Material prices swing with the chemical market too, so quotes can vary by season.

How much does spray foam insulation cost in 2026?

Q: How much does spray foam insulation cost?

Spray foam runs about $1 to $5 per board foot installed, with open-cell at the low end and closed-cell at the high end. A typical job lands between $1,500 and $8,000 or more, depending on the area, the foam type, and the access. Whole-home or new-construction jobs run higher.

Spray foam insulation costs about $1 to $5 per board foot installed, which puts a typical job between $1,500 and $8,000 or more. Open-cell sits at the low end and closed-cell at the high end. Three things move the number: the area and thickness, open-cell versus closed-cell, and how hard the space is to reach.

We build websites and marketing for insulation and exterior contractors, so we see both sides — what homeowners pay and what it costs a crew to spray it. Below are the real ranges, the open-versus-closed-cell choice, and an honest take on when a cheaper insulation does the job better.

Open-cell vs closed-cell, with costs

Open-cell foam

$1–$2.50/board ft

Softer and lighter, about R-3.5 to R-4 per inch. A strong air sealer at a lower price. Good for interior walls and accessible attic spaces where moisture is not a concern.

Closed-cell foam

$2.50–$5+/board ft

Denser, about R-6 to R-7 per inch, and it doubles as an air and moisture barrier. The pick for basements, rim joists, crawl spaces, and tight cavities where you need more R-value in less depth.

As a rough whole-job guide: a small attic might run $1,500 to $3,000, a larger area or a closed-cell crawl space $4,000 to $8,000, and a whole-home or new-construction spray job well into five figures.

What moves the price

→ Square footage and thickness — more area and a higher target R-value both cost more.
→ Foam type — closed-cell can be roughly double open-cell per board foot.
→ Access — a tight crawl space or a finished wall that must be opened raises labor.
→ Prep — removing old insulation, masking, and protecting the home add to the quote.
→ Material market — foam chemical prices swing seasonally, so quotes vary over the year.

When spray foam is not the smart buy

• A simple, accessible attic floor. Blown-in cellulose or fiberglass often delivers most of the benefit for a fraction of the cost.
• A tight budget on an older home. Air-sealing the obvious gaps and adding batts first can capture much of the savings.
• If a contractor pushes whole-home closed-cell when only a crawl space needs it. Match the product to the problem area.

Spray foam earns its premium where you need air sealing and high R-value in one step — rim joists, crawl spaces, vaulted ceilings, and humid climates. Get two or three itemized quotes before a four-figure job.

If you run an insulation company

Homeowners researching spray foam compare quotes and read reviews for weeks before they call. A fast site with a clear open-versus-closed-cell explainer, real install photos, a quote request, and an AI assistant that answers "do you do crawl spaces" and "roughly what does an attic cost" after hours is how you win that research phase. We run our own home-service companies on this stack, so it is built to book estimates, not just look good.

Start Getting Leads is $249/mo for the site plus AI lead capture; Grow in Google is $597/mo with the SEO content engine that publishes cost and comparison pages monthly; Own Your Market adds CRM and reputation automation from $1,750/mo. Month-to-month, you own the site and domain, and we will build a free demo in 48 hours. Related: insulation websites, insulation marketing, cost guides, and the AI receptionist.

We don't post stock testimonials. On a 15-minute call we screen-share the real dashboards behind our own businesses — live leads, rankings, and the exact page that produced each one. See the proof →

Common questions

How much does it cost?

About $1–$5 per board foot installed; a typical job runs $1,500–$8,000+, with open-cell at the low end and closed-cell at the high end.

Open-cell or closed-cell?

Open-cell is cheaper and a good air sealer; closed-cell costs more, has higher R-value per inch, and adds a moisture barrier for crawl spaces and rim joists.

Is it worth it over fiberglass?

Sometimes. For a simple attic, blown-in often delivers most of the benefit for far less. Match the product to the problem.

Run an insulation company?
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