Insulation Installation Cost Per Sq Ft (2026): Batt, Blown, Spray Foam
By Fabio Freire, Founder & General Contractor at EZ-Estimates. Published 2026-05-01.
Insulation Installation Cost Per Sq Ft (2026): Batt, Blown, Spray Foam Pricing
Insulation is hidden behind drywall but homeowners care about R-values and energy savings. Quote it correctly and you protect both your margin and the building envelope. Underspec it and the customer files a callback in winter.
Here are the 2026 insulation rates per square foot installed.
How Insulation Is Priced
Insulation is priced per square foot of surface area being insulated, with rates varying by:
- Material type (batt, blown, foam, rigid)
- R-value target (higher R = thicker, more material)
- Application location (wall, attic, basement, rim joist)
- Access difficulty (open framing vs blow-in retrofit)
Per square foot installed (2026):
- Fiberglass batts (R-13 to R-21 walls): $0.50-1.50/sq ft
- Fiberglass batts (R-30 to R-49 attic): $0.75-2.00/sq ft
- Mineral wool batts: $1.00-2.50/sq ft
- Blown cellulose (attic): $1.00-2.50/sq ft
- Blown fiberglass (attic): $0.80-2.00/sq ft
- Open cell spray foam: $1.00-2.50/sq ft per inch
- Closed cell spray foam: $1.50-4.00/sq ft per inch
- Rigid foam board (1 inch XPS): $1.50-3.00/sq ft installed
- Rim joist seal (closed cell): $5-12/LF
These are 2026 ranges for residential. Commercial pricing typically runs 20-40% lower per sq ft due to scale.
Insulation Material Costs (2026)
Fiberglass batts:
- R-13 (2x4 wall): $0.50-1.00/sq ft material
- R-15 high-density (2x4 wall): $0.70-1.30/sq ft
- R-21 (2x6 wall): $0.70-1.40/sq ft
- R-30 (attic): $0.80-1.60/sq ft
- R-38 (attic): $1.00-2.00/sq ft
- R-49 (cold climate attic): $1.30-2.50/sq ft
Mineral wool (Rockwool):
- R-15 wall: $1.00-1.80/sq ft material
- R-23 wall: $1.30-2.20/sq ft
- R-30 attic: $1.50-2.80/sq ft
Blown insulation:
- Cellulose blown to R-38 attic: $0.80-1.80/sq ft material
- Fiberglass blown to R-38 attic: $0.60-1.50/sq ft material
Spray foam:
- Open cell (R-3.5 per inch): $0.80-1.80/sq ft per inch
- Closed cell (R-6.5 per inch): $1.20-3.00/sq ft per inch
- Standard wall application (R-21 closed cell at 3.5 inch): $4-10/sq ft installed
Rigid foam:
- EPS (expanded polystyrene, R-3.8/inch): $0.50-1.20/sq ft for 1 inch
- XPS (extruded, R-5/inch): $0.80-1.80/sq ft for 1 inch
- Polyiso (R-6.5/inch faced): $1.20-2.50/sq ft for 1 inch
Vapor barrier and accessories:
- 6 mil polyethylene: $0.05-0.15/sq ft
- Vapor-retarder paint (alternative): $0.30-0.60/sq ft
- Air sealing caulk and foam: $50-200 per house
- Baffles for soffit ventilation: $3-6 each
Insulation Labor Costs
Per square foot labor only:
- Fiberglass batt install (open framing): $0.20-0.60/sq ft
- Fiberglass batt install (retrofit drill-and-fill): $1.50-3.50/sq ft
- Blown cellulose attic: $0.30-0.80/sq ft
- Open cell spray foam: $0.50-1.20/sq ft per inch
- Closed cell spray foam: $0.80-1.80/sq ft per inch
- Rigid foam board: $0.80-2.00/sq ft
Air sealing labor:
- Air sealing pass (caulk all penetrations): $0.30-0.80/sq ft of attic
- Rim joist sealing (basement): $5-12/LF
- Can light retrofit covers: $25-60 each
Crew rates:
- Lead insulator: $30-50/hour wage
- Helper: $20-30/hour wage
- Spray foam crew (2-3 people + truck): $150-250/hour burdened
Site Conditions That Change Pricing
- Difficult attic access (low slope, no walkway): +30-50% labor
- Crawl space insulation (kneeling, dust mask required): +20-40% labor
- Existing insulation removal first: $1-3/sq ft for vacuum extraction
- Knob-and-tube wiring present: requires updating before blown insulation, electrician subcontract
- Vermiculite present (old attics, may contain asbestos): $5-15/sq ft for licensed abatement
- Spray foam in occupied home: tenants must be out 24-48 hours, schedule impact
- Code-required vapor barrier: +$0.10-0.30/sq ft material + labor
- Continuous insulation on exterior (rigid board over sheathing): +$2-5/sq ft
Markup and Margin
Standard markup on insulation: 25-50%. Spray foam contractors typically run higher margins (40-50%) because of equipment overhead. Batt installers run 25-35%.
Calculate yours with the free markup calculator.
Common Mistakes That Kill Margin
1. Underbidding spray foam. Spray foam is priced per board foot (1 sq ft x 1 inch thick = 1 board foot). A wall cavity at R-21 closed cell needs 3.5 inches = 3.5 board feet per sq ft of wall. Wrong calculation = significant underbid.
2. Forgetting baffles. Attic insulation requires baffles in eaves to maintain soffit ventilation. $3-6 each, easy to miss but required by code.
3. Skipping the air seal. Insulation without air sealing is far less effective. Customer complaints about cold rooms 3 months later. Always include air sealing line item ($300-1,000 per house).
4. Knob-and-tube surprise. Old houses have knob-and-tube wiring. Cannot be covered by blown insulation per code. Discovery during work requires electrician + delay. Always inspect before bidding.
5. R-value mismatch. Customer asks for R-49 attic. You quote based on R-38. Different material, different cost. Always specify the R-value in the bid and stick to it.
Sample Estimate: 2,000 sq ft Home Insulation Package
| Item |
Qty |
Unit |
Unit Cost |
Total |
| Wall batts (R-21, 2x6 walls) |
1,800 |
sq ft |
$1.00 |
$1,800 |
| Wall batt install labor |
1,800 |
sq ft |
$0.40 |
$720 |
| Attic blown cellulose (R-49) |
1,200 |
sq ft |
$1.40 |
$1,680 |
| Attic blown labor |
1,200 |
sq ft |
$0.50 |
$600 |
| Attic baffles |
24 |
each |
$5 |
$120 |
| Rim joist closed cell foam |
200 |
LF |
$9 |
$1,800 |
| Air sealing pass (attic + basement) |
1 |
lot |
$700 |
$700 |
| Vapor barrier (basement walls) |
800 |
sq ft |
$0.10 |
$80 |
| Disposal of old insulation |
1 |
lot |
$400 |
$400 |
| Setup + cleanup |
1 |
lot |
$300 |
$300 |
| Subtotal cost |
|
|
|
$8,200 |
| Markup (35%) |
|
|
|
$2,870 |
| Total bid |
|
|
|
$11,070 |
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