Insulation Cost Estimating: Cost Per Square Foot, R-Value Math, and Labor
Insulation cost estimating is how you turn square footage and board feet into a clean bid price. This page walks through unit pricing, labor productivity, waste factors, and markup in plain English so you can price any insulation job with confidence.
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Cost Per Square Foot by Type
The simplest way to sanity-check a bid is cost per square foot. Here are typical 2026 installed numbers for standard commercial and residential work.
Fiberglass Batt
- R-13 (2x4 wall) — $1.10 to $1.80 per SF
- R-15 high-density (2x4) — $1.30 to $2.00 per SF
- R-19 (2x6 wall) — $1.40 to $2.10 per SF
- R-21 (2x6) — $1.50 to $2.20 per SF
- R-30 (ceiling) — $1.80 to $2.50 per SF
- R-38 (ceiling) — $2.10 to $2.80 per SF
Mineral Wool
- R-13 (2x4) — $1.80 to $2.60 per SF
- R-21 (2x6) — $2.40 to $3.30 per SF
- R-23 (2x6 sound) — $2.60 to $3.50 per SF
Blown Insulation
- Cellulose R-30 attic — $1.00 to $1.50 per SF
- Cellulose R-38 attic — $1.20 to $1.80 per SF
- Cellulose R-49 attic — $1.50 to $2.20 per SF
- Fiberglass loose-fill R-38 — $1.30 to $2.00 per SF
- Dense-packed cellulose in walls — $1.80 to $2.80 per SF
Spray Foam
- Open cell at 3.5 inch (R-13) — $1.75 to $2.80 per SF
- Open cell at 5.5 inch (R-20) — $2.60 to $4.20 per SF
- Closed cell at 2 inch (R-13) — $2.20 to $3.60 per SF
- Closed cell at 3 inch (R-20) — $3.20 to $5.20 per SF
Rigid Board
- 1 inch polyiso — $1.40 to $2.10 per SF
- 2 inch polyiso — $2.50 to $3.75 per SF
- 1 inch XPS — $1.50 to $2.30 per SF
- 2 inch XPS — $2.75 to $4.10 per SF
Material Pricing
Batt Pack Prices
- R-13 fiberglass kraft-faced pack (covers ~133 SF) — $55 to $85
- R-19 fiberglass kraft-faced pack (covers ~75 SF) — $55 to $80
- R-21 high-density pack (covers ~88 SF) — $75 to $110
- R-13 mineral wool bundle (covers ~60 SF) — $70 to $100
Blown Bag Prices
- Cellulose bag (25-30 lb) — $12 to $18
- Fiberglass loose-fill bag — $28 to $40
Spray Foam Material
Open cell typically runs $0.30 to $0.50 per board foot in raw material. Closed cell runs $0.65 to $1.10 per board foot in raw material. Prices move with chemical markets; always pull a supplier quote for the month you are bidding.
Rigid Board
- 2 inch polyiso 4x8 sheet — $35 to $55
- 2 inch XPS 2x8 sheet — $38 to $58
- 1 inch EPS 4x8 sheet — $10 to $18
Labor Rates and Productivity
Base Wage
Insulation installers earn $22 to $40 per hour base in most US markets in 2026. Union markets pay at the upper end. Spray foam applicators earn $30 to $55 per hour base due to certification requirements.
Loaded Labor Cost
Add 30 to 55 percent for fringes (benefits, workers comp, payroll taxes). Loaded journey rate is $35 to $60 per hour for installers and $50 to $85 for spray foam applicators.
Productivity Rates
- Batt install — 1,500 to 3,000 SF per 2-person crew day
- Rigid board on walls — 800 to 1,500 SF per 2-person crew day
- Rigid board on flat roof — 3,000 to 5,000 SF per 3-person crew day
- Blown attic insulation — 2,500 to 5,000 SF per 2-person crew day
- Dense-pack blown walls — 800 to 1,500 SF per 2-person crew day
- Open cell spray foam — 4,000 to 8,000 BF per 2-person crew day
- Closed cell spray foam — 2,500 to 5,000 BF per 2-person crew day
Adjust for conditions: High walls over 10 feet reduce productivity 15 to 25 percent. Occupied buildings reduce 20 to 35 percent. Complex geometry reduces 15 to 25 percent. Cold weather cuts spray foam output by 20 to 30 percent.
R-Value Math and Cost Efficiency
Dollars Per R Per Square Foot
A quick way to compare insulation options. Divide installed cost per SF by R-value to get cost per R per SF.
- R-13 batt at $1.50 = $0.115 / R / SF
- R-21 batt at $2.00 = $0.095 / R / SF
- R-20 closed cell at $3.50 = $0.175 / R / SF
- R-38 blown cellulose at $1.40 = $0.037 / R / SF
Blown cellulose in an open attic is the lowest cost per R. Closed cell is the most expensive per R but adds air and vapor barrier value, which means less air sealing cost.
Continuous Insulation Add
Energy codes often require R-5 to R-10 of continuous insulation on exterior walls in addition to cavity insulation. This is a separate line item typically running $1.25 to $2.75 per SF.
Waste and Loss Factors
- Batt, standard wall — 5 to 8 percent
- Batt, cut-heavy or irregular — 8 to 12 percent
- Rigid board — 5 to 10 percent
- Tapered rigid — 8 to 15 percent
- Blown, settling allowance — 2 to 5 percent
- Spray foam — already included in unit price
- Vapor barrier poly — 10 to 15 percent for laps
Assembly Pricing
Many estimators price by assembly rather than by piece. This bundles material, labor, and incidentals into one clean number per SF.
Common Assembly Prices (2026)
- R-21 batt + 6 mil poly — $2.00 to $2.85 per SF
- R-38 blown attic + baffles — $1.45 to $2.15 per SF
- R-20 closed cell spray + thermal barrier — $4.50 to $6.50 per SF
- R-30 flat roof polyiso 2 layers — $3.75 to $5.50 per SF
- Rim joist closed cell 2 inch — $4.00 to $6.50 per LF
Markup, Overhead, and Profit
Direct Cost
Material plus loaded labor plus equipment use for this job. No office costs, no profit.
Markup Layers
- Material markup — 15 to 30 percent
- Labor markup — 10 to 20 percent
- Equipment markup — 10 to 20 percent (spray foam trucks are expensive)
- Overhead — 8 to 12 percent of subtotal
- Profit — 8 to 15 percent
- Bond and insurance — 1 to 3 percent on bonded public jobs
Sample Bid Build-Up
A 10,000 SF batt job with R-21 walls, R-38 ceiling, and a vapor barrier:
- Material: $18,500
- Labor (loaded): $9,800
- Equipment: $600
- Subtotal direct: $28,900
- Overhead 10 percent: $2,890
- Profit 12 percent: $3,815
- Bid: $35,605 ($3.56/SF)
Extras and Add-Ons
- Air sealing pre-insulation — $0.35 to $1.20 per SF
- Rafter baffles at soffits — $3 to $8 each
- Attic access hatch insulation cover — $75 to $175
- Knee wall seal — $8 to $14 per LF
- Rim joist foam seal — $5 to $9 per LF
- Thermal barrier paint over spray foam — $0.75 to $1.50 per SF
- Debris removal and cleanup — $500 to $2,500 lump sum
AI Insulation Estimating
AI insulation estimating software like PILRS reads the plan set, identifies wall types from the legend, calculates square footage by assembly, applies the specified R-value, and produces a priced bid sheet in under an hour. Estimators who used to spend a full day on a mid-size job now finish in 60 to 90 minutes, including review.
Benefits
- Consistent quantities every time
- Automatic opening deductions
- Slope factors applied correctly
- Material and labor pricing pulled from your unit price database
- Exportable to Excel, CSV, or GC bid forms
Frequently Asked Questions
How much does insulation cost per square foot installed?
Installed cost by type in 2026: R-13 fiberglass batt $1.10 to $1.80 per square foot, R-21 batt $1.50 to $2.20, R-13 mineral wool $1.80 to $2.60, blown cellulose at R-38 $1.20 to $1.80, open cell spray foam $1.40 to $2.00 per inch of thickness per square foot, closed cell spray foam $2.00 to $3.25 per inch per square foot, 2-inch polyiso rigid roof board $2.50 to $3.75 per square foot installed.
What is the cost per board foot of spray foam?
Open cell spray foam runs $0.45 to $0.80 per board foot installed. Closed cell spray foam runs $1.00 to $1.80 per board foot installed. Remember one board foot equals one square foot at one inch thick. So closed cell at 3 inches on a 1,000 SF wall is 3,000 board feet times say $1.30 = $3,900 installed. Prices shift with petrochemical markets, so always pull a current quote before locking in a bid.
What is a typical insulation contractor labor rate?
Insulation installers make $22 to $40 per hour base wage in most markets in 2026. Fringes add 30 to 55 percent for benefits, workers comp, and payroll taxes, so loaded labor cost is typically $35 to $60 per hour. Spray foam crews cost more because they include a certified applicator and helper with specialized equipment, usually $80 to $140 per hour for a two-person crew plus machine.
How fast can an insulation crew install batts?
A two-installer crew can install 1,500 to 3,000 square feet of batt insulation per day on typical residential and light commercial walls. Faced batts install faster than unfaced because no separate vapor barrier is needed. Tight access, high walls, and mineral wool (which is denser and harder to cut) slow the rate. For blown attic insulation, one crew with a blowing machine can install 2,500 to 5,000 square feet of attic per day.
How much does closed cell spray foam cost compared to open cell?
Closed cell costs about 2x to 2.5x the price of open cell per board foot. Open cell runs $0.45 to $0.80 per board foot installed, closed cell runs $1.00 to $1.80. For the same R-value, closed cell uses less thickness (R-6.5 per inch vs R-3.7 per inch) so the gap narrows on an installed R-value basis. For R-21 a 5.5 inch open cell costs roughly the same as 3.25 inch closed cell in many markets.
What waste factor should I use for insulation pricing?
For batt insulation, use 5 to 8 percent waste on standard walls and 8 to 12 percent on cut-heavy walls with lots of openings. For rigid board, 5 to 10 percent. For blown, 2 to 5 percent for settling. Spray foam contractors include overspray loss in the unit price so you typically do not add waste on top. Always round up to the full pack, full bag, or full set when ordering.
How do I calculate R-value cost effectiveness?
Divide the installed cost per square foot by the R-value to get cost per R per square foot. Example: R-13 batt at $1.50 per SF = $0.115 per R per SF. R-21 batt at $2.00 per SF = $0.095 per R per SF. R-21 is more cost-efficient. Closed cell at $1.40 per board foot and R-6.5 per inch = $0.215 per R per SF, which is higher but adds air and vapor barrier value.
What is the markup on an insulation bid?
Insulation contractors typically mark up material 15 to 30 percent and labor 10 to 20 percent. Add overhead (8 to 12 percent) and profit (8 to 15 percent) on top. Total markup above direct cost is usually 25 to 40 percent on standard jobs. Spray foam jobs carry higher margins because of equipment cost and the specialty skill premium.
How much does attic insulation cost to install?
Blown cellulose at R-38 typically costs $1.20 to $1.80 per square foot installed. Blown fiberglass at R-38 runs $1.30 to $2.00. Adding rafter baffles at soffits adds $0.25 to $0.50 per square foot of eave area. If the job requires air sealing before insulation, add another $0.50 to $1.50 per square foot. A 2,000 SF attic upgrade typically runs $3,000 to $6,500 turnkey.
What labor productivity rate should I use for spray foam?
A two-person spray foam crew with a fully rigged truck can apply 4,000 to 8,000 board feet per day of open cell, or 2,500 to 5,000 board feet per day of closed cell. Closed cell is slower because of the two-inch-per-pass limit (multiple passes needed for thick installs). Weather and access affect output; cold weather significantly slows spray foam because of material preheat requirements.
How does AI insulation estimating software improve bid accuracy?
AI estimating tools like PILRS read the plan set and produce accurate square footage by assembly type automatically. This eliminates the math errors that come from measuring by hand and adding up hundreds of small numbers on a calculator. The estimator then applies unit prices and waste factors to the AI-generated quantities. Faster bids plus more accurate quantities usually translate into a higher win rate and better margin.
What extras should I include in an insulation bid?
Air sealing at penetrations, vapor barrier if specified, rafter baffles at soffit vents, attic access cover insulation, rim joist seal, around-plumbing sealing, mechanical ventilation for spray foam cure, protective coverings for floors and finished surfaces, debris cleanup, and final inspection. These extras usually add 5 to 15 percent to a bare batt or blown bid and are expected by the GC.
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