Insulation cost by type (2026)
National average ranges per square foot, installed. Use the calculator above for a city-specific estimate.
| Type |
Cost per sq ft |
R-value per inch |
Best for |
| Fiberglass batts | $0.40–$1.50 | R-2.9 to R-3.8 | Walls, attic floors, DIY |
| Blown-in cellulose | $0.60–$2.30 | R-3.2 to R-3.8 | Attic top-up, retrofit walls |
| Blown-in fiberglass | $0.50–$1.80 | R-2.2 to R-2.9 | Attics, low-cost retrofit |
| Open-cell spray foam | $1.50–$3.50 | R-3.5 to R-3.7 | Interior walls, sound dampening |
| Closed-cell spray foam | $2.50–$5.50 | R-6.0 to R-7.0 | Crawlspaces, exterior walls, max insulation |
| Mineral wool / Rockwool | $1.00–$2.50 | R-3.0 to R-3.3 | Fire/sound performance, walls |
Cost of insulation per square foot
For a typical 2,000-sq-ft home, full insulation retrofit ranges from $1,500 to $11,000 depending on type and where you’re installing. Attic-only blown-in cellulose runs $1,500–$3,500 (the most common project). Wall insulation retrofit (drilling and blowing in) runs $2,500–$6,500. Closed-cell spray foam through a whole house runs $5,000–$11,000.
Cost is driven by R-value target (climate-zone-dependent), accessibility (open new construction is much cheaper than retrofit through finished walls), and removal of old insulation if needed ($1–$2 per sq ft).
Recommended R-value by climate zone
- Zone 1-2 (hot — FL, TX, AZ, southern CA): Attic R-30 to R-49, walls R-13 to R-15
- Zone 3 (warm — GA, NC, SC, AL): Attic R-30 to R-60, walls R-13 to R-15
- Zone 4 (mixed — VA, KY, MO, OK): Attic R-49 to R-60, walls R-13 to R-21
- Zone 5 (cold — NJ, NY, OH, IN): Attic R-49 to R-60, walls R-13 to R-21
- Zone 6-7 (very cold — MN, ND, MT): Attic R-60+, walls R-21 to R-25
Insulation cost by area of home
Attic insulation
Most common project. Blown-in cellulose top-up: $1,500–$3,500. Full attic spray foam: $4,000–$8,000.
Wall insulation (retrofit)
Drilling holes through siding to blow in cellulose: $2,500–$6,500 for an average home.
Crawlspace insulation
Closed-cell spray foam most common: $1,500–$5,000 depending on access and area.
Basement insulation
Rim joists + walls: $1,200–$4,500. Often required for finished basement code compliance.
Garage insulation
$800–$2,500 for walls and ceiling. Worth it if garage is attached to living space.
Whole-house retrofit
Combining attic + walls + crawlspace: $5,000–$11,000 for an average 2,000 sq ft home.
Insulation cost by city
Local insulation pricing benchmarks across major US metros.
New York, NY
Los Angeles, CA
Chicago, IL
Houston, TX
Phoenix, AZ
Philadelphia, PA
Dallas, TX
Atlanta, GA
Miami, FL
Charlotte, NC
Seattle, WA
Denver, CO
Boston, MA
Columbus, OH
Indianapolis, IN
Minneapolis, MN
Detroit, MI
Milwaukee, WI
Portland, OR
Nashville, TN
Baltimore, MD
St. Louis, MO
Kansas City, MO
Cincinnati, OH
Frequently asked questions about insulation cost
How much does insulation cost per square foot?
Insulation costs $0.40 to $5.50 per square foot installed depending on type. Fiberglass batts are cheapest at $0.40–$1.50/sq ft, blown-in cellulose runs $0.60–$2.30/sq ft, and closed-cell spray foam costs the most at $2.50–$5.50/sq ft (but delivers nearly double the R-value per inch).
Is spray foam insulation worth the extra cost?
For attics in extreme climates (very hot or very cold), closed-cell spray foam pays back in 5–9 years through energy savings. For interior walls or low-stress areas, fiberglass or cellulose at one-third the cost makes more financial sense. Spray foam wins when you also need air sealing, moisture control, or maximum R-value in a thin space.
How much does it cost to insulate an attic?
Attic insulation runs $1,500–$3,500 for blown-in cellulose top-up to bring R-value to current code (typically R-49 to R-60). Spray foam attic conversion (creating a sealed, conditioned attic) costs $4,000–$8,000 but can cut HVAC bills 15–30%.
Will new insulation lower my heating and cooling bills?
Adding insulation to an under-insulated home typically cuts heating and cooling bills 10–30%. The biggest gains come from attic insulation (heat rises, attic is the #1 leak point). Wall insulation retrofits typically save 5–15%. Most projects pay back in 3–8 years through energy savings, then continue saving for the life of the insulation (50+ years for cellulose, 100+ for spray foam).
Are there rebates for insulation upgrades?
The federal 25C tax credit (which previously covered 30% of insulation materials up to $1,200/year)
expired Dec 31 2025 — insulation installed on or after Jan 1 2026 does not qualify for the federal credit. Many state utilities still offer rebates of $200–$1,700, and the IRA HEAR program (income-qualified) is still active in many states. Check
dsireusa.org for what’s available where you live.
