Last updated: 2026-07-06
Quick Answer
Enter the area to insulate and pick the material to get a per-square-foot cost range. Fiberglass batts run $0.50-$2.50/sf, blown-in $1-$3/sf, and closed-cell spray foam $2-$5/sf installed. A typical 1,500 sq ft attic in blown-in runs $1,500-$4,500. Add $1-$3.50/sf if the old insulation has to come out first.
Inputs you'll need
- Area to insulate in square feet (the surface you cover - attic floor, wall area, or crawl-space floor)
- Insulation type: fiberglass batts, blown-in, spray foam, rigid board, or mineral wool
- Whether the old insulation needs to be removed first ($1-$3.50/sf)
- Whether the job needs an air-sealing pass ($0.50-$1.50/sf)
- Your target R-value - attics usually want R-38 to R-60
Related tools: Drywall Calculator for the wall area you are insulating behind, Contractor Estimate Template to turn these numbers into a formal bid.
Measure the surface you cover: attic floor, wall area, or crawl-space floor - not the room footprint.
Enter the area to insulate to see a detailed cost estimate.
Insulation Cost Guide
Per-square-foot costs by insulation type, what drives the bid, and how the materials compare.
Insulation Cost per Square Foot by Type (2026)
Installed insulation runs about $0.50-$5 per square foot in 2026 depending on the material, with spray foam at the top and fiberglass batts at the bottom. Price by the area you are covering, not the room's floor space, since walls and slopes add up.
- Fiberglass batts: $0.50-$2.50 per sq ft installed. The budget standard for open stud and joist bays.
- Blown-in (cellulose or fiberglass): $1-$3 per sq ft installed. Fast to fill an attic.
- Open-cell spray foam: $1-$2 per sq ft installed at 3 inches. Great sound and air control, lower R per inch.
- Closed-cell spray foam: $2-$5 per sq ft installed. Highest R per inch and a vapor barrier in one.
- Rigid foam board: $2.26-$3.77 per sq ft installed. For basement walls and continuous exterior sheathing.
- Mineral wool: $1.50-$3 per sq ft installed. Fire and sound rated, denser than fiberglass.
These are installed prices that already include labor. Prices vary by region and by how cut-up the space is, so quote from local supplier rates in 2026 and get multiple bids on any subbed spray foam work.
Key Takeaways
- Fiberglass batts: $0.50-$2.50/sf; blown-in: $1-$3/sf installed
- Closed-cell spray foam is the priciest at $2-$5/sf but adds the most R per inch
- Price the surface area you cover, not the room floor space
What Drives an Insulation Bid
The material is only half the bid - access, removal, and air sealing are what move the number. Two 1,500 sq ft attics can price hundreds apart depending on what is already up there.
- Old insulation removal: Ripping out and bagging wet, moldy, or rodent-fouled insulation runs $1-$3.50 per sq ft on its own.
- Air sealing: Caulk and foam around penetrations, top plates, and can lights adds $0.50-$1.50 per sq ft and makes the R-value actually work.
- Access: A tight attic, a crawl space you belly-crawl through, or a two-story wall all add labor hours.
- R-value target: Attics usually want R-38 to R-60. More inches means more material and, for batts, sometimes a second layer.
Add these as their own line items so the homeowner sees what they are paying for. Run your true material and labor cost, then apply markup with our markup calculator to land the right price.
Key Takeaways
- Old insulation removal is a separate $1-$3.50/sf line, not a freebie
- Air sealing at $0.50-$1.50/sf is what makes the R-value perform
- Attic and crawl-space access drives the labor hours
Spray Foam vs. Batts vs. Blown-In
There is no single best insulation - each type wins in a different spot. I have pulled out soggy batts in PNW crawl spaces and replaced them with closed-cell for exactly this reason.
- Fiberglass batts: Cheapest and DIY-friendly for open walls, but they sag, leave gaps, and do nothing to stop air.
- Blown-in cellulose: Fills an attic fast and gets into odd cavities, but it settles over time and loses some R.
- Open-cell spray foam: Seals air and deadens sound at a lower cost than closed-cell, but it is not a vapor barrier.
- Closed-cell spray foam: Highest R per inch, adds structural rigidity, and stops water vapor - the go-to for crawl spaces and rim joists.
For a fast, itemized bid that splits material and labor, drop your numbers into the calculator above. Then send the client a clean estimate instead of a napkin figure.
Key Takeaways
- Batts are cheapest but do not stop air movement
- Closed-cell foam wins in damp crawl spaces and rim joists
- Blown-in fills an attic fast but settles over time
Common Insulation Estimating Mistakes
The fastest way to lose money on an insulation job is quoting off the floor square footage instead of the surface you actually cover. A sloped attic or a two-story wall has far more area than the footprint suggests.
- Measuring the wrong area. Vaulted ceilings, knee walls, and gable ends all add square footage the floor plan hides.
- Forgetting removal. If the old insulation has to come out first, that is a full $1-$3.50/sf line you cannot skip.
- Skipping air sealing. New insulation over leaky top plates underperforms. Price the caulk-and-foam pass so the job actually works.
- Ignoring waste on spray foam. Foam yield drops in cold weather and on cut-up surfaces. Pad the set count.
- No allowance for surprises. Rot, knob-and-tube wiring, or a rodent nest changes the scope the second you open it up. Put a change-order clause in the estimate.
Itemize every phase so nothing gets left off, then send it as a clean, signable estimate the client can act on.
Key Takeaways
- Quote the covered surface area, not the room floor space
- Removal and air sealing are separate line items, not freebies
- Add a change-order clause for rot and old wiring you cannot see yet
Insulation cost by type and area (2026)
Installed cost ranges that already include labor. Add $1-$3.50/sf for old-insulation removal and $0.50-$1.50/sf for an air-sealing pass. Excludes rot repair, wiring fixes, and a separate vapor barrier.
| Insulation Type | $/sq ft | 500 sf | 1,500 sf |
|---|---|---|---|
| Fiberglass batts | $0.50 - $2.50 | $250 - $1,250 | $750 - $3,750 |
| Blown-in (cellulose/fiberglass) | $1 - $3 | $500 - $1,500 | $1,500 - $4,500 |
| Open-cell spray foam | $1 - $2 | $500 - $1,000 | $1,500 - $3,000 |
| Closed-cell spray foam | $2 - $5 | $1,000 - $2,500 | $3,000 - $7,500 |
| Rigid foam board | $2.26 - $3.77 | $1,130 - $1,885 | $3,390 - $5,655 |
| Mineral wool | $1.50 - $3 | $750 - $1,500 | $2,250 - $4,500 |
Prices vary by region - get multiple bids from local contractors before you commit.
What gets left out of insulation quotes
- Old insulation removal. An "insulation price" often assumes bare framing. Ripping out wet, moldy, or rodent-fouled material and bagging it is a full $1-$3.50 per square foot the headline number skips.
- Air sealing. New insulation over leaky top plates and can lights underperforms. The caulk-and-foam pass at $0.50-$1.50/sf is what makes the R-value real, and it is rarely in a cheap quote.
- Access. A belly-crawl crawl space or a tight attic scuttle adds labor hours. If the crew cannot stand up, the job slows down and the price goes up.
- The right area. Vaulted ceilings, knee walls, and gable ends carry more square footage than the floor plan shows. Quote the surface you cover, not the room footprint.
- Surprises behind the wall. Rot, knob-and-tube wiring, or a rodent nest changes the scope the moment you open it up. A good estimate carries a change-order clause for exactly that.
Related tools
- Drywall Calculator - Size the wall area you insulate behind
- Basement Finishing Cost Calculator - Price a full basement build-out including insulation
- Contractor Estimate Template - Turn your insulation numbers into a line-item bid
- Markup Calculator - Convert your target margin into the right price
- Garage Cost Calculator - Estimate a full garage build including insulation
Once your insulation costs are dialed in, EstimationPro turns the estimate into a proposal, sends it automatically, follows up with the homeowner, and handles invoicing and deposit collection - so you win more of the bids you already send and spend less time chasing paperwork.
How to Use This Calculator
Enter the Area to Insulate
Input the surface area you are covering in square feet - the attic floor, the wall area, or the crawl-space floor. Measure the surface, not the room footprint, since sloped and vertical areas add up fast.
Select Insulation Type
Choose fiberglass batts, blown-in, open-cell or closed-cell spray foam, rigid foam board, or mineral wool. The material is the biggest cost driver - closed-cell spray foam runs three to five times the price of fiberglass batts per square foot.
Add Removal and Air Sealing
Check "Remove Old Insulation" if the existing material has to come out first ($1-$3.50/sf), and "Air Sealing Pass" to caulk and foam the leaks so the new R-value actually performs ($0.50-$1.50/sf).
Review the Cost Breakdown
See a low-to-high range for the insulation, removal, and air sealing as separate line items, plus a total estimate you can hand a client.
Insulation Cost Formula
Total = (Area x Cost per SF) + (Area x Removal) + (Area x Air Sealing)Where:
- Fiberglass Batts
- = $0.50-$2.50/sf installed
- Blown-In
- = $1-$3/sf installed
- Open-Cell Spray Foam
- = $1-$2/sf installed
- Closed-Cell Spray Foam
- = $2-$5/sf installed
- Rigid Foam / Mineral Wool
- = Rigid $2.26-$3.77/sf, mineral wool $1.50-$3/sf
- Add-Ons
- = Removal $1-$3.50/sf, air sealing $0.50-$1.50/sf
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Frequently Asked Questions
How much does insulation cost per square foot?
Installed insulation costs $0.50 to $5 per square foot in 2026 depending on the material. Fiberglass batts run $0.50-$2.50/sf, blown-in $1-$3/sf, open-cell spray foam $1-$2/sf, closed-cell spray foam $2-$5/sf, rigid foam board $2.26-$3.77/sf, and mineral wool $1.50-$3/sf. These prices already include labor. Prices vary by region, so get multiple bids on any spray foam work.
How much does it cost to insulate a house?
Insulating a whole house typically runs $3,000 to $10,000+ in 2026 depending on size, type, and how much old material has to come out. A 1,500 sq ft attic with blown-in insulation runs $1,500-$4,500, while spray-foaming a crawl space or rim joist costs more per square foot. Add $1-$3.50/sf if the old insulation needs removal first. Get local quotes since labor and material prices vary by region.
How much does spray foam insulation cost?
Spray foam costs $1-$5 per square foot installed. Open-cell foam runs $1-$2/sf and seals air and sound; closed-cell foam runs $2-$5/sf and adds the highest R per inch plus a built-in vapor barrier. Closed-cell is the go-to for damp crawl spaces and rim joists. Foam yield drops in cold weather, so a winter job or a cut-up surface uses more material - pad your set count when you bid.
What should an insulation estimate include?
A complete insulation estimate should list: the material installed (batts, blown-in, or foam), old insulation removal if needed, an air sealing pass, the R-value target, access notes for tight attics or crawl spaces, cleanup and disposal, and exclusions like rot repair, wiring fixes, or a vapor barrier. Break each out as its own line so the homeowner sees what they are paying for.
How do contractors price insulation for a client?
I price insulation by the square foot of surface I cover, add a separate line for removal and air sealing, then apply markup for overhead and profit. For an attic I start with the material rate, add $0.50-$1.50/sf if it needs air sealing, and price removal at $1-$3.50/sf when old insulation has to come out. Use our Contractor Estimate Template to turn those line items into a clean bid, and our markup calculator to set the final price.
Is spray foam or fiberglass better?
It depends on the job. Fiberglass batts are cheapest ($0.50-$2.50/sf) and fine for open walls, but they sag, leave gaps, and do nothing to stop air. Spray foam costs more ($1-$5/sf) but seals air leaks and, in closed-cell form, blocks moisture. I use closed-cell foam in damp PNW crawl spaces where I have pulled out soggy fiberglass more times than I can count. For a dry, open wall on a budget, batts win.
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