Insulation Cost Calculator: 2026 Pricing Guide

Insulation costs vary widely based on material type, R-value required, location in the home, and whether you install it yourself or hire a contractor. This guide breaks down the real numbers so you can budget accurately.

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Average Insulation Costs at a Glance

Material	DIY Cost per sq ft	Installed Cost per sq ft
Fiberglass batts (R-13)	$0.30–$0.55	$1.00–$1.75
Fiberglass batts (R-19)	$0.45–$0.70	$1.25–$2.00
Blown fiberglass (attic)	$0.35–$0.65	$1.20–$2.25
Blown cellulose (attic)	$0.30–$0.55	$1.00–$2.00
Spray foam (open cell)	$0.50–$1.00	$1.50–$3.00
Spray foam (closed cell)	$1.50–$3.00	$3.00–$7.00
Mineral wool batts	$0.60–$1.20	$1.50–$2.75
Rigid foam board	$0.50–$1.50	$1.75–$3.50

Typical Total Project Costs

Attic Insulation (1,500 sq ft attic)

• Blown fiberglass to R-49: $500–$950 DIY, $1,800–$3,400 professional
• Adding R-19 to existing R-11: $400–$700 DIY, $1,200–$2,500 professional
• Full removal and replacement: $3,000–$6,000 professional (needed if old insulation has mould or pest damage)

Wall Insulation (2,000 sq ft home, standard construction)

• Fiberglass batts, full home (new construction): $1,200–$2,200 DIY, $3,500–$6,000 professional
• Blown-in retrofit (existing walls): $2,500–$5,000 professional (difficult DIY)
• Spray foam retrofit: $5,000–$12,000 professional

Basement and Crawlspace

• Batt insulation, rim joists (perimeter, 100 LF): $200–$400 DIY
• Spray foam, crawlspace walls (800 sq ft): $2,400–$5,600 professional
• Rigid foam on basement walls (1,000 sq ft): $600–$1,500 DIY

Cost Breakdown by Material

Fiberglass Batts — Most Common, Most Affordable

Fiberglass batts are the default choice for most DIY insulation projects:

• Advantages: Cheap, widely available, DIY-friendly, no special equipment
• Disadvantages: Can sag over time in walls, fibres irritate skin/lungs during install
• Best for: Walls and floors in new construction, attic floor insulation top-ups

Pricing:

• R-13 (2×4 walls): $0.30–$0.55 per sq ft
• R-15 (2×4 walls, high-density): $0.40–$0.65 per sq ft
• R-19 (2×6 walls): $0.45–$0.70 per sq ft
• R-30 (attic): $0.60–$0.90 per sq ft

Blown-In Insulation — Best for Attic Top-Ups

Blown fiberglass or cellulose is the preferred method for adding insulation to existing attics:

• Advantages: Fills voids completely, fast application, cost-effective
• Disadvantages: Requires renting/borrowing blower machine, fibres settle slightly
• Best for: Attic upgrades, retrofit applications

Cellulose vs Fiberglass Blown-In:

• Cellulose is made from recycled paper and performs slightly better (R-3.7/inch vs R-2.2–2.7/inch for blown fibreglass)
• Cellulose is generally slightly cheaper
• Fiberglass settled depth is more stable long-term

Spray Foam — Premium Performance

Spray polyurethane foam (SPF) is the highest-performing insulation option:

• Advantages: Air seals and insulates simultaneously, highest R-value per inch, long lifespan
• Disadvantages: Much higher cost, requires professional installation for large areas, complex chemistry
• Best for: Crawlspaces, basement walls, hard-to-reach areas, sealing against moisture

Open Cell (OCF): R-3.7/inch, soft and flexible, good for interior walls and attic rafters Closed Cell (CCF): R-6.5/inch, rigid and moisture-resistant, best for basements and crawlspaces

Mineral Wool — Premium Batts

Mineral wool (Rockwool/Roxul) batts cost more but offer compelling advantages:

• Better soundproofing than fiberglass
• Fire resistant (melts at 1,470°C, fiberglass at 540°C)
• Water repellent — won't absorb moisture
• Same R-value options as fiberglass

Premium cost (20–40% more than fiberglass) is worth it for fire walls, party walls, and basement installations.

What Affects Insulation Cost?

Location in the Home

• Attic: Easiest access, most cost-effective to insulate
• Exterior walls: Much more expensive (requires opening walls or drilling)
• Basement: Moderate difficulty, often requires framing before insulating
• Crawlspace: Difficult access drives up labour cost significantly

R-Value Requirements

Higher R-value = more material = higher cost. This is roughly linear:

• R-19 costs approximately twice as much material as R-11
• R-49 attic costs approximately 2.5x more than an R-19 installation

Climate Zone

Your local building code sets minimum R-values. Northern homes (Zones 5–8) require higher R-values, meaning higher material costs. However, energy savings are also proportionally higher.

Access and Existing Insulation

• Existing insulation in good condition: add blown-in on top (cheaper)
• Existing insulation with mould or pest damage: full removal required ($1–$2 per sq ft extra)
• Finished walls: retrofit requires special equipment (more expensive than open wall)

DIY vs Professional: Cost Comparison

When to DIY

DIY insulation makes financial sense when:

• Working in an accessible, open attic
• Installing batts in open stud cavities (new construction)
• Adding blown-in to existing attic (borrow the machine)

Typical DIY savings: $1,500–$3,500 on a full attic insulation project

When to Hire a Professional

Professional installation is worth it when:

• Spray foam is involved (chemistry expertise required)
• Walls are finished (retrofit through existing wall)
• Crawlspace has difficult access
• You suspect moisture or mould issues (needs assessment first)

Government Rebates and Tax Credits

Federal Tax Credit (US): The Inflation Reduction Act provides a 30% tax credit (up to $1,200/year) for qualifying insulation improvements. Keep your receipts.

Utility Rebates: Many utilities offer $0.10–$0.30 per sq ft rebate for insulation upgrades. Check your utility company's website or call them before starting.

State Programs: Several states offer additional rebates. Check dsireusa.org for current programs in your state.

Return on Investment

A well-insulated home saves energy year-round:

• Attic insulation upgrade (Zone 5, 1,500 sq ft):

  • Cost: $500–$1,000 DIY
  • Annual savings: $300–$600
  • Payback period: 1–3 years

• Full home air sealing + insulation:

  • Cost: $3,000–$6,000 professional
  • Annual savings: $600–$1,200
  • Payback period: 5–8 years
  • Home value increase: $2,000–$5,000

Calculate Your Project Cost

Use our free calculator to get a tailored estimate based on your specific measurements and material choices.

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Updated: November 2025 | HomeFixCalc Team