Insulation Cost Calculator 2026 — Attic, Walls, Spray Foam
Price insulation by material and R-value. Fixr: $1,750–$5,500 to blow 8–18 in. into a 1,500 sq ft attic, $2,500–$12,000 to spray-foam an attic.
Insulation Cost Calculator
Attic floor, about the footprint of the top floor. 50–10,000.
DOE: R-30 in zone 1, R-49 in zones 2–3, R-60 in zones 4–8.
Adjusts the labor share by local construction wages (BLS, May 2025).
Also include:
homeprojectestimator.com · · https://homeprojectestimator.com/calculators/insulation-cost/
Estimated insulation cost
$2,500
Typical range $2,050 – $2,900
Cost per sq ft
$2.50
Where the money goes
- Blown-in cellulose, about 14.2 in for R-49 (installed) $2.07–$2.89 per sq ft$2,050 – $2,900
National average. Pick your state and metro area to adjust the labor share (about 40% of this job) to local wages. Get three written quotes before you commit to a budget.
Prices from Fixr (2025–2026 pages). Asbestos-bearing vermiculite, mold cleanup and drywall patching after drill-and-fill are not included.
This calculator prices an insulation job from four facts: where the insulation goes, how many square feet, which material, and the R-value you want to add. It returns a typical cost, a range and a breakdown, with optional removal of old insulation, air sealing and a crawl space vapor barrier.
For the most common attic jobs on a 1,000 sq ft attic: blowing cellulose to R-49 comes to $2,050–$2,900, removing the old insulation first raises that to $3,050–$5,900, and open-cell spray foam to R-38 runs $4,650–$9,000. Fixr's range for spray-foaming an attic is $2,500–$12,000.
How to use this calculator
- Where. Attic floor is insulation laid or blown between and over the ceiling joists. Existing closed walls are filled through small holes drilled from outside, without removing drywall. Open walls are bare studs in new construction or a gut renovation. Crawl space means insulation under the floor above it. Basement walls are the foundation walls of a basement.
- Area (sq ft). For an attic, use the footprint of the floor below: a 30 × 40 ft house has a 1,200 sq ft attic floor. For walls, multiply the perimeter by the wall height and subtract windows and doors. For a crawl space, use the floor area above it. For basement walls, multiply the perimeter by the wall height.
- Material. The list changes with the location, so you only see materials that are actually used there. Closed walls are dense-filled with blown cellulose.
- R-value to add. The thermal resistance you are adding, not the total. If the attic already has a few inches, ENERGY STAR's retrofit table recommends a lower added R-value than for an empty attic. For blown-in attic insulation and spray foam, a higher R-value means more inches and a higher price. Batts, rigid board and drill-and-fill walls are priced per square foot, so the R-value there picks the product rather than the price.
- Also include. Removal of old insulation, professional air sealing, and, for crawl spaces, a vapor barrier.
- Your state adjusts the labor share to local wages.
Insulation cost in 2026
| Material | Installed price | R per inch |
|---|---|---|
| Fiberglass batts or rolls | $0.30–$2.10 per sq ft | 2.2–3.8 |
| Mineral wool (Rockwool) batts | $1.50–$2.00 per sq ft (Today's Homeowner); Fixr lists $1.40–$2.10 | 3.7–4.3 |
| Blown-in fiberglass | $1.65–$2.60 per sq ft | 2.5–3.5 |
| Blown-in cellulose | $1.75–$3.80 per sq ft | 3.2–3.7 |
| Drill-and-fill, existing walls | $1.75–$3.30 per sq ft | 3.2–3.7 (cellulose) |
| Rigid foam board | $1–$4 per sq ft | 4.5–5 (polystyrene) |
| Open-cell spray foam | $0.44–$0.65 per board foot, material only | about 3.8 |
| Closed-cell spray foam | $1–$1.50 per board foot, material only | about 7 |
Sources: Fixr, How Much Does Insulation Installation Cost? 2026 Data, updated January 29, 2026 (batts, mineral wool, R per inch for batts, mineral wool and board); Today's Homeowner, Rockwool vs Fiberglass, updated March 13, 2025 (Rockwool installed); Fixr, Cost to Install Blown-In Insulation, updated August 29, 2025 (blown-in, drill-and-fill); Fixr, Crawl Space Insulation Cost, updated August 29, 2025 (rigid board); Fixr, Cost to Install Spray Foam Insulation, updated January 31, 2025 (spray foam).
| Location | Installed price per sq ft |
|---|---|
| Attic | $0.50–$2.30 |
| Existing walls (blown-in or spray foam) | $0.50–$4.50 |
| New construction or open walls | $0.30–$2.10 |
| Crawl space or basement | $0.25–$4.50 |
Source: Fixr, How Much Does Insulation Installation Cost? 2026 Data, updated January 29, 2026. Fixr's national average for a 2,000 sq ft home with fiberglass batts is $4,700, range $2,000–$7,400.
| Add-on | Price |
|---|---|
| Remove old insulation | $1–$3 per sq ft |
| Professional air sealing | $600–$2,300 |
| Crawl space vapor barrier | $1,500–$4,000 |
| Spray foam or installer labor | $0.25–$2.50 per sq ft |
| Energy audit | $145–$420, average $250 |
Sources: Fixr, Home Insulation (January 29, 2026); Fixr, Energy Audit Cost (January 31, 2025); Fixr, Crawl Space Insulation Cost (August 29, 2025).
Fixr's pages do not agree on blown-in attic prices. The 2026 overview gives $0.50–$2.30 per sq ft for attics; the blown-in page gives $1,750–$5,500 for 1,500 sq ft at 8–18 inches, which is $1.17–$3.67 per sq ft. The calculator uses the blown-in page because it ties the price to depth, and depth is what the R-value sets.
Attic insulation cost by job
| Attic job | Range | Typical | Source |
|---|---|---|---|
| Blown-in, 8–18 in added, 1,500 sq ft | $1,750–$5,500 | — | Fixr |
| Fully insulating a 1,000 sq ft attic | $2,000–$3,250 | — | Fixr |
| Blown fiberglass to R-38, 1,000 sq ft | $1,850–$2,600 | $2,250 | Calculator |
| Blown cellulose to R-49, 1,000 sq ft (default) | $2,050–$2,900 | $2,500 | Calculator |
| Reinsulate: remove old, blow cellulose to R-49, 1,000 sq ft | $3,050–$5,900 | $4,500 | Calculator |
| Open-cell spray foam to R-38, 1,000 sq ft | $4,650–$9,000 | $6,850 | Calculator |
| Closed-cell spray foam to R-49, 1,000 sq ft | $7,250–$13,000 | $10,150 | Calculator |
| Spray foam an attic | $2,500–$12,000 | — | Fixr |
| Spray foam the underside of the roof deck | $2,400–$8,000 | — | Fixr |
Calculator rows are national prices built from the Fixr rates above. Fixr rows: Cost to Install Blown-In Insulation (August 29, 2025), Attic Insulation Cost (September 1, 2022), Cost to Install Spray Foam Insulation (January 31, 2025).
Other jobs from the calculator:
| Job | Range | Typical |
|---|---|---|
| 1,200 sq ft of existing walls, drill-and-fill | $2,100–$3,950 | $3,050 |
| 800 sq ft crawl space, batts plus vapor barrier | $2,300–$5,600 | $3,950 |
What drives the price
- Area. Every material line scales with square feet.
- Depth, set by the R-value. Blown cellulose needs about 14 inches for R-49 at Fixr's midpoint of R-3.45 per inch, and blown fiberglass about 16 inches at R-3.0. The calculator prices attic blown-in at $0.146–$0.204 per sq ft per inch, worked out from Fixr's 1,500 sq ft attic figure.
- Material. Closed-cell foam is the most expensive per inch, about $1–$1.50 per board foot for material alone, but it delivers about R-7 per inch.
- Access. Existing closed walls cost more than open studs: $1.75–$3.30 per sq ft for drill-and-fill against $0.30–$2.10 for open walls.
- Removal. Taking out old insulation adds $1–$3 per sq ft and can double a small attic job.
- Labor. Fixr says labor is 30–50% of an insulation job, at $30–$80 per hour.
Cost breakdown
- Insulation installed. For blown-in attics, batts, rigid board and drill-and-fill walls, Fixr gives installed prices only, so the calculator shows one installed line rather than inventing a material and labor split.
- Spray foam material and spray crew labor. Spray foam is priced by the board foot, so the calculator shows material (inches × area × price per board foot) and labor ($0.25–$2.50 per sq ft) separately.
- Add-ons. Removal per square foot, and air sealing and the crawl space vapor barrier as whole-job prices.
Not included: patching and painting the drill holes in existing walls, asbestos-containing vermiculite removal, mold remediation, baffles and attic hatch insulation, and repairs to rodent damage. The state adjustment assumes 40% labor, the middle of Fixr's 30–50%.
Prices by state and metro area
Only the labor share moves with your state. The calculator multiplies 40% of the estimate by the state's construction wage index from the U.S. Bureau of Labor Statistics (Occupational Employment and Wage Statistics, May 2025) and leaves the material share at national prices.
For the default 1,000 sq ft attic at R-49, national typical $2,500:
| State | Wage index | Typical estimate |
|---|---|---|
| Washington | 1.26 | $2,750 |
| Illinois | 1.25 | $2,750 |
| California | 1.20 | $2,700 |
| Texas | 0.84 | $2,350 |
| Arkansas | 0.74 | $2,250 |
Insulation moves less with wages than painting because more of the bill is material. Read how regional cost adjustments work for the method.
The calculator also prices 387 metro areas from the same BLS survey. The default job comes to $2,500 nationally; in Seattle-Tacoma-Bellevue, WA (wage index 1.34) it is $2,850, and in Miami-Fort Lauderdale-West Palm Beach, FL (0.89) $2,400. Choose the metro area below your state for the closest figure.
Attic reinsulation: top up or remove and replace?
Removing old attic insulation is not a requirement for adding more: ENERGY STAR's retrofit table is written for attics that already hold 3–4 inches, and it simply asks for a lower added R-value. Removal at $1–$3 per sq ft is worth paying for when the old material is wet, moldy, soiled by pests, or when you need clear access to air-seal the ceiling below. For a 1,000 sq ft attic the calculator gives:
| Reinsulation job, 1,000 sq ft attic | Range | Typical |
|---|---|---|
| Top up with blown cellulose, R-38 added (zones 2–3) | $1,600–$2,250 | $1,950 |
| Top up with blown cellulose, R-49 added (zones 4–8) | $2,050–$2,900 | $2,500 |
| Remove old, blow fiberglass to R-38 | $2,850–$5,600 | $4,250 |
| Remove old, blow cellulose to R-49 | $3,050–$5,900 | $4,500 |
| Remove old, air-seal, blow cellulose to R-49 | $3,650–$8,200 | $5,950 |
| Remove old, open-cell spray foam to R-38 | $5,650–$12,000 | $8,850 |
Two cases change the plan:
- Vermiculite. EPA describes it as a pebble-like, pour-in product, usually gray-brown or silver-gold. Its advice is to assume it contains asbestos and not disturb it, and to hire a professional asbestos contractor if it has to be removed or if you plan renovations that would disturb it. Get that quote before planning the rest of the job; the calculator does not include it.
- Mold or moisture. Fix the source — a roof leak, a bathroom fan venting into the attic — and remediate before reinsulating. The cost depends on the extent, so it is not in the estimate.
Old spray foam is harder to take out than loose fill: Fixr puts removal at $1.50–$3 per sq ft for most jobs, closer to $5 when it has to be chipped off by hand. In a crawl space, Fixr puts removal of damaged insulation alone at $300–$1,000.
Spray foam in the attic
Fixr puts the cost to spray-foam an attic at $2,500 to $12,000, and spraying the underside of the roof deck at $2,400 to $8,000 on average. Foam can go on the attic floor, the walls or the underside of the roof deck. The calculator prices it from the board foot up, over the attic floor area you enter:
| 1,000 sq ft attic | Depth | Range | Typical |
|---|---|---|---|
| Open cell to R-30 | 7.9 in | $3,750–$7,650 | $5,700 |
| Open cell to R-38 | 10 in | $4,650–$9,000 | $6,850 |
| Closed cell to R-30 | 4.3 in | $4,550–$8,950 | $6,750 |
| Closed cell to R-38 | 5.4 in | $5,650–$10,600 | $8,150 |
| Closed cell to R-49 | 7 in | $7,250–$13,000 | $10,150 |
At the same R-value, spray foam's typical price is roughly three and a half to four and a half times that of blown cellulose. What the extra buys: Fixr calls foam a very effective way of sealing air gaps, and closed cell packs about R-7 per inch against the R-3.0 to R-3.45 the calculator uses for blown fiberglass and cellulose, which matters where depth is limited. Blowing cellulose to R-49 and paying for professional air sealing still comes to $2,650–$5,200 for 1,000 sq ft. Whether foam pays back depends on your climate, energy prices and how leaky the attic is; an energy audit with a blower-door test shows where the losses are before you choose.
Wall insulation and mineral wool (Rockwool)
| Situation | Price per sq ft | Notes |
|---|---|---|
| Open walls, batts | $0.30–$2.10 | New construction or a gut renovation |
| Mineral wool (Rockwool) batts | $1.50–$2.00 installed | Fiberglass averages $0.60–$1.20 on the same page |
| Existing walls, drill-and-fill | $1.75–$3.30 | Holes drilled, cavities dense-filled, holes plugged |
| Open-cell spray foam, 3.5 in | $1.54–$2.28 material + $0.25–$2.50 labor | 3.5 board feet per sq ft of wall |
| Rigid foam board | $1–$4 | Crawl space and basement walls |
Sources: Fixr, Home Insulation (January 29, 2026); Today's Homeowner, Rockwool vs Fiberglass (March 13, 2025); Fixr, Cost to Install Blown-In Insulation (August 29, 2025); Fixr, Cost to Install Spray Foam Insulation (January 31, 2025); Fixr, Crawl Space Insulation Cost (August 29, 2025).
Rockwool R-15. Neither source prices R-15 separately; their ranges are for mineral wool batts in general. Fixr gives mineral wool R-3.7 to R-4.3 per inch and Today's Homeowner about R-4.0, so R-15 takes roughly 3.5 to 4 inches — about the depth of a 2×4 wall cavity. At $1.50–$2.00 per sq ft installed, 1,000 sq ft of open wall in mineral wool costs about $1,500–$2,000, against $600–$1,200 for fiberglass at Today's Homeowner's average. This Old House notes that stone wool is naturally fire-resistant, repels moisture and absorbs sound. The calculator prices batts at Fixr's $0.30–$2.10, a range that covers both fiberglass and mineral wool; for mineral wool, read the upper part of the batt estimate. R-15 also appears in the R-value tables: ENERGY STAR lists R-15 board for basement walls in zones 4C and 5–8, and Fixr says crawl spaces in mild climates may make do with R-13 or R-15.
How much insulation you need: DOE R-values by climate zone
The Department of Energy's page on insulation and air sealing for the home improvement credit (October 29, 2024) lists the 2021 IECC minimums for an uninsulated attic and an uninsulated 2×4 wall:
| Climate zone | Attic (uninsulated) | Wood-frame wall (uninsulated 2×4) |
|---|---|---|
| 1 | R-30 | R-13 |
| 2 | R-49 | R-13 |
| 3 | R-49 | R-20, or R-13 + R-5 continuous |
| 4 (except marine) | R-60 | R-20 + R-5 continuous, or R-13 + R-10 continuous |
| 5 and marine 4 | R-60 | same as zone 4 |
| 6, 7 and 8 | R-60 | same as zone 4 |
Source: U.S. Department of Energy, Energy-Efficient Home Improvement Credit Insulation and Air-Sealing Essentials, October 29, 2024 (from the 2021 IECC).
If the attic already has 3–4 inches, ENERGY STAR's retrofit table recommends adding R-25 in zone 1, R-38 in zones 2 and 3, and R-49 in zones 4 through 8. For floors over a crawl space it lists R-13 in zones 1–2, R-19 in zones 3 and 4A/4B, R-30 in zones 4C–6 and R-38 in zones 7–8. For basement and crawl space walls: R-5 board or R-13 batts in zone 3, R-10 board or R-13 batts in zones 4A/4B, and R-15 board or R-19 batts in zones 4C and 5–8.
Air sealing and insulation
Insulation slows heat moving through a surface; air sealing stops air leaking through gaps around wiring, plumbing, attic hatches and top plates. The DOE notes that air sealing reduces the air that leaks into and out of a home. It is easiest to do before new insulation is blown over the gaps, which is why the calculator offers it alongside removal. Fixr puts professional air sealing at $600–$2,300 and an energy audit, which shows where the leaks are, at $145–$420.
How much any of this saves depends on what is there now, your climate, your heating and cooling system and your energy prices, so be wary of a flat savings percentage. Start from the R-value gap: an attic with a few inches of old insulation in zone 5 has far more to gain than one already near R-49.
Federal tax credit and rebates in 2026
The 25C Energy Efficient Home Improvement Credit paid 30% of qualifying insulation and air-sealing materials, up to $1,200 a year. The IRS page, last reviewed April 28, 2026, says the credit applies to property placed in service on or after January 1, 2023 and before December 31, 2025. Insulation installed in 2026 does not qualify.
Many utilities and states run their own insulation and air-sealing rebates, with their own amounts and rules. DSIRE (dsireusa.org) lists state and utility incentives, and some programs require pre-approval or an energy audit before the work starts, so check before you sign a contract.
Sources
- Fixr, How Much Does Insulation Installation Cost? 2026 Data — batt and location prices, mineral wool $1.40–$2.10 per sq ft and R-3.7–4.3, removal $1–$3 per sq ft, labor 30–50% and $30–$80 per hour, R per inch, national average (updated January 29, 2026). link
- Fixr, Cost to Install Blown-In Insulation — attic $1,750–$5,500 for 1,500 sq ft at 8–18 in, blown fiberglass and cellulose prices, drill-and-fill walls (updated August 29, 2025). link
- Fixr, Cost to Install Spray Foam Insulation — price per board foot, R per inch, attic $2,500–$12,000, roof deck $2,400–$8,000, removal of old foam $1.50–$3 (up to $5) per sq ft, air-gap sealing (updated January 31, 2025). link
- Fixr, Crawl Space Insulation Cost — batts, rigid board, spray foam, labor, vapor barrier, removal, R-13 or R-15 in mild climates (updated August 29, 2025). link
- Fixr, Attic Insulation Cost — $2,000–$3,250 for a 1,000 sq ft attic (updated September 1, 2022). link
- Fixr, Energy Audit Cost — air sealing $600–$2,300, energy audit $145–$420 (updated January 31, 2025). link
- Today's Homeowner, Rockwool vs Fiberglass: Which Insulation Is Better? — Rockwool $1.50–$2.00 per sq ft installed, about R-4.0 per inch, fiberglass $0.60–$1.20 per sq ft (updated March 13, 2025). link
- This Old House, Benefits of Stone Wool Insulation — fire resistance, moisture and sound properties of stone wool (updated June 5, 2026). link
- U.S. Environmental Protection Agency, Protect Your Family from Asbestos-Contaminated Vermiculite Insulation — how to recognize vermiculite, do not disturb, hire a professional (updated April 17, 2026). link
- U.S. Department of Energy, Energy-Efficient Home Improvement Credit Insulation and Air-Sealing Essentials — 2021 IECC R-values by climate zone (October 29, 2024). link
- ENERGY STAR, Recommended Home Insulation R-Values — retrofit R-values for attics, floors and basement walls (undated page, based on the 2021 IECC). link
- Internal Revenue Service, Energy Efficient Home Improvement Credit — credit dates and limits (reviewed April 28, 2026). link
- U.S. Bureau of Labor Statistics, Occupational Employment and Wage Statistics — construction wages by state (May 2025). link
Related
Frequently Asked Questions
How much does attic insulation cost?
Fixr puts blown-in attic insulation at $1,750–$5,500 for a 1,500 sq ft attic with 8 to 18 inches of added depth, and its attic page gives $2,000–$3,250 for fully insulating a 1,000 sq ft attic. This calculator's default, 1,000 sq ft of blown cellulose to R-49, comes out at $2,050–$2,900, typical $2,500, or about $2.50 per square foot.
How much does spray foam attic insulation cost?
Fixr puts spray-foaming an attic at $2,500–$12,000 and the underside of the roof deck at $2,400–$8,000. Priced by the board foot — $0.44–$0.65 for open cell, $1–$1.50 for closed cell, plus $0.25–$2.50 per sq ft of labor — a 1,000 sq ft attic comes to $4,650–$9,000 in open-cell foam to R-38 and $7,250–$13,000 in closed-cell foam to R-49.
How much does it cost to reinsulate an attic?
Fixr adds $1–$3 per sq ft to remove old insulation, so clearing a 1,000 sq ft attic costs $1,000–$3,000 before the new material goes in. With removal and blown cellulose to R-49, the calculator puts that attic at $3,050–$5,900, typical $4,500. If the old layer is dry and clean, ENERGY STAR's retrofit table lets you top it up instead and skip the removal.
What R-value should attic insulation be?
The Department of Energy's table, taken from the 2021 International Energy Conservation Code, lists R-30 for an uninsulated attic in climate zone 1, R-49 in zones 2 and 3, and R-60 in zones 4 through 8. ENERGY STAR's retrofit table asks for less when 3–4 inches are already there: R-25 in zone 1, R-38 in zones 2–3 and R-49 from zone 4 north.
How much does Rockwool R-15 insulation cost per square foot?
Today's Homeowner puts Rockwool at $1.50–$2.00 per sq ft installed, against $0.60–$1.20 for fiberglass, and Fixr lists mineral wool at $1.40–$2.10 per sq ft. Neither prices R-15 separately. At Fixr's R-3.7 to R-4.3 per inch, R-15 takes about 3.5 to 4 inches of mineral wool, roughly the depth of a 2×4 wall cavity.
Is spray foam insulation worth the extra cost?
In the calculator, closed-cell foam to R-49 over a 1,000 sq ft attic is typically $10,150, against $2,500 for blown cellulose to the same R-value. Foam earns some of that back: Fixr calls it very effective at sealing air gaps, and closed cell gives about R-7 per inch. An energy audit ($145–$420, Fixr) shows whether air leaks are the real problem before you pay for foam.
How much does a crawl space vapor barrier cost?
Fixr puts a crawl space vapor barrier at $1,500–$4,000. Insulating the same crawl space adds $1–$2 per sq ft for fiberglass batts, $1–$4 for rigid foam board or $2–$5 for spray foam. Fixr's national average for spray-foaming an 800 sq ft crawl space is $2,000. Tick the vapor barrier box after choosing Crawl space to add it.
Is there still a federal tax credit for insulation in 2026?
No, not for new work. The IRS page on the Energy Efficient Home Improvement Credit, reviewed in April 2026, says the 30% credit, capped at $1,200 a year, applies to qualifying property placed in service on or after January 1, 2023 and before December 31, 2025. Check your utility and state programs for rebates instead.