Spray Foam Insulation Cost: Open vs Closed Cell (3 References)

Spray foam insulation costs $1.50 to $5.00 per square foot installed, or $1,455 to $4,337 for a typical project.¹² The national average single project is $2,888 (Angi, 4,048 projects); fully insulating a whole home runs $10,000 to $30,000 (Fixr).¹³ Prices below are national averages* for 2026.

*National averages, not local quotes. Your price depends on foam type (open vs closed cell), thickness, area size, and access. Most contractors charge minimum job fees of $1,000 to $2,000 (HomeGuide).²

$2,888

average project, Angi

$1.50 – $5.00

per sq ft, HomeGuide

$0.60 – $3.10

per board ft, Angi

$20,000

whole-home average, Fixr

Quick math: 1,000 sq ft at HomeGuide’s $1.50 to $5.00 per square foot = $1,500 to $5,000, matching its size table, our arithmetic.² The averages look contradictory — $2,888 (Angi) versus $20,000 (Fixr) — because Angi averages single-area projects (an attic, a crawl space) while Fixr prices whole-home insulation, our reading.¹³

Open-cell vs closed-cell

Type	HomeGuide (per sq ft)	Angi (per board ft)	R-value per inch	Best for
Open-cell	$1.50 – $3.50	$0.60 – $1.60	3.5 – 3.7	Interior walls, sound dampening, moderate-climate attics
Closed-cell	$3.00 – $5.00	$1.30 – $3.10	5 – 7	Exterior walls, basements, crawl spaces, moisture-prone areas

A board foot is one square foot at one inch thick, so multiply by depth to compare: 3 inches of open-cell at Angi’s $0.60 to $1.60 per board foot = $1.80 to $4.80 per square foot, overlapping HomeGuide’s band, our arithmetic.¹² Closed-cell costs roughly double but insulates nearly twice as well per inch and resists water and pests (HomeGuide).²

Cost by area size (HomeGuide)

Area (sq ft)	Cost installed
800	$1,200 – $4,000
1,000	$1,500 – $5,000
1,500	$2,250 – $7,500
2,000	$3,000 – $10,000
2,500	$3,750 – $12,500
3,000	$4,500 – $15,000

Angi’s wider $1 to $5 per square foot band produces the same 1,000-sq-ft range at the low end ($1,000 to $5,000), so the sources agree on area pricing.¹²

Cost by location (HomeGuide)

Location	Cost
Attic	$3,000 – $8,000
Basement	$2,500 – $9,000
Crawl space	$2,000 – $4,000
Garage	$2,000 – $7,500

Labor runs $50 to $100 per hour (Angi), and hard-to-reach areas in existing homes cost more: Fixr prices existing-wall work at $3.15 to $7.50 per square foot versus $2.75 to $6.50 in new construction.¹³

Whole-home insulation (Fixr)

Insulating an entire 2,000-sq-ft home with 6 inches of mixed open and closed cell averages $20,000, ranging $10,000 to $30,000 (Fixr).³ Its low end, $7,000, is 7 inches of open-cell on an attic floor only; the $40,000 high end is a net-zero 3,000-sq-ft build with 10 inches of closed-cell (Fixr).³

Worked examples

Example 1 — 1,000-sq-ft attic floor, open-cell. $1,500 to $3,500 (HomeGuide’s open-cell rate); Angi’s project average $2,888 lands mid-band.¹²

Example 2 — crawl space, closed-cell. $2,000 to $4,000 (HomeGuide).²

Example 3 — existing 2,000-sq-ft home, walls + attic. 2,000 sq ft x $3.15 to $7.50 = $6,300 to $15,000 (Fixr’s existing-home rate), our arithmetic.³

FAQ

Open or closed cell? Open for interior walls and sound; closed for basements, crawl spaces, and anywhere moisture reaches — it also adds R-5 to R-7 per inch versus R-3.5 to R-3.7 (HomeGuide).²

Why do quotes have minimums? Rig setup and mobilization: most pros charge $1,000 to $2,000 minimum job fees, so bundling areas in one visit saves money (HomeGuide), our judgment.²

Is spray foam worth it over batts? It air-seals as it insulates, which batts can’t, but costs several times more per square foot, our judgment. Compare our attic insulation cost guide for blown and batt alternatives.

Can old insulation stay? Moldy material must go first: mold remediation runs $1,125 to $3,345 before spraying (Angi).¹

DIY spray foam? Small canned-foam gaps yes; rig-applied jobs no — off-ratio foam cures wrong and the fix is a full removal, our judgment.

Sources

Angi, How Much Does Spray Foam Insulation Cost? (2026 data, 4,048 projects).
HomeGuide, How Much Does Spray Foam Insulation Cost? (2026).
Fixr, Cost to Install Spray Foam Insulation