- Blown-in attic insulation usually costs $0.75 to $2.73 a square foot installed, about $1.66 typical.
- Batts run about $0.90 to $2.39 a sq ft. Spray foam costs the most, about $2 to $5 for open-cell.
- ENERGY STAR recommends R-49 to R-60 in most attics. Ask every quote for the R-value, not just the inches.
- Removing old insulation adds about $1 to $1.50 a sq ft, and sealing air leaks first matters as much as the insulation.
How much does insulation cost per square foot
Insulation is priced per square foot of the area covered: the attic floor, or the wall surface. We combined the installed ranges from Bob Vila, This Old House, Fixr, Thumbtack and HomeAdvisor. Where three or more guides give a range, the low is the middle of their lows, the high the middle of their highs and the typical price the middle of their midpoints.
| Insulation | Installed per sq ft | 1,000 sq ft, typical |
|---|---|---|
| Rigid foam board | $0.25 to $2 | $1,125 |
| Batts or rolls | $0.90 to $2.39 | $1,520 |
| Blown-in fiberglass or cellulose | $0.75 to $2.73 | $1,658 |
| Drill and fill, existing walls | $0.75 to $3.25 | $2,000 |
| Spray foam, open-cell | $2 to $5 | $3,500 |
| Spray foam, closed-cell, 2 in | $2.50 to $5.80 | $4,150 |
As whole jobs, Bob Vila's typical attic insulation project is $1,500 to $3,500, about $2,500. Fixr's average to insulate a 2,000 sq ft home with fiberglass batts or rolls is $4,700. HomeAdvisor puts attics at $1 to $7 a square foot and walls at $1 to $4.
How much insulation you need: R-value by climate
R-value measures how well insulation slows heat. Higher is better. ENERGY STAR publishes the attic levels that pay off in each climate zone, based on the 2021 International Energy Conservation Code:
| Climate zone | Uninsulated attic | Attic with 3 to 4 in now |
|---|---|---|
| 1 | R-30 | Add R-25 |
| 2 and 3 | R-49 | Add R-38 |
| 4A and 4B | R-60 | Add R-49 |
| 4C, 5 and 6 | R-60 | Add R-49 |
| 7 and 8 | R-60 | Add R-49 |
Depth follows from the material. Fixr lists fiberglass at R-2.2 to R-3.8 an inch, cellulose at R-3.1 to R-3.8, mineral wool at R-3.7 to R-4.3, polyurethane foam at R-3.6 to R-7 and polystyrene board at R-4.5 to R-5. Reaching R-60 with blown fiberglass or cellulose takes about 16 to 27 inches, which is why attic jobs are priced by area but quoted by R-value.
How do you know if you need more? Look across the attic floor. If the insulation is level with or below the tops of the ceiling joists, it is well short of the R-49 to R-60 in the table, since joists are usually only 6 to 10 inches deep. Measure the depth in a few spots with a ruler and compare it with the inches needed for your zone. Other signs are rooms that are cold in winter or hot in summer while others are fine, ice dams along the roof edge, and high heating or cooling bills for the size of the house. An energy audit, which Bob Vila puts at $145 to $420, uses a blower door and an infrared camera to show exactly where heat is getting out.
For walls, ENERGY STAR's advice is to blow insulation into empty wall cavities whenever siding comes off, and to add R-5 to R-10 of insulating sheathing under new siding in zones 4 to 8. For basement and crawl space walls it suggests R-5 to R-15 board, or R-13 to R-19 batts, depending on the zone.
Blown-in vs batts vs spray foam
- Blown-in (loose-fill). Fiberglass or cellulose blown over the attic floor with a machine. Fills around joists, wires and odd shapes, and is the usual choice for topping up an existing attic. Also used to dense-pack closed walls through small holes.
- Batts and rolls. Pre-cut fiberglass or mineral wool that fits between studs and joists. Cheap and familiar, and the usual choice for open walls in new construction or a remodel. Gaps and compression cut their real performance, so the install quality matters.
- Spray foam. Sprayed as a liquid that expands and seals as it insulates. Open-cell is softer and cheaper. Closed-cell is denser, adds more R-value an inch and blocks moisture. It costs the most, and installers need special training and gear.
- Rigid foam board. Sheets of polystyrene or polyiso, used on basement walls, under siding and on roof decks. High R-value an inch and adds a moisture barrier when the seams are taped.
Thumbtack's materials-only figure for fiberglass batts shows how R-value drives price: about $0.12 to $0.16 a sq ft at R-11 against $0.55 to $0.60 at R-38.
Removal, air sealing and the other costs
| Item | Typical price | Source |
|---|---|---|
| Remove old insulation | $1 to $1.50 a sq ft | Fixr, Bob Vila, Thumbtack |
| Attic cleaning and prep | $100 to $300 | Bob Vila |
| Attic inspection | $100 to $300 | Bob Vila |
| Energy audit | $145 to $420 | Bob Vila |
| Mold removal in the attic | $1,500 to $3,500 | Bob Vila |
| Installer labor by the hour | $40 to $80 | HomeAdvisor |
Old insulation can usually stay if it is dry and clean; new loose-fill goes right on top. It should come out when it is wet, moldy, full of rodent droppings, or in the way of sealing air leaks. Bob Vila puts a full remove-and-replace at about $2 to $8.50 a square foot.
Air sealing is the step that makes insulation work. Warm air leaking up through gaps around lights, plumbing, wires, flues and the attic hatch carries heat straight past the insulation. Sealing those gaps with foam and caulk before the insulation goes in is cheap compared with the job and is part of ENERGY STAR's attic project. Once a deep layer of blown insulation is down, those gaps are buried and much harder to reach, so it really has to happen first, before the insulation crew arrives or as their first step.
Insulation cost by part of the house and home size
Where the insulation goes changes the price as much as what it is. HomeAdvisor's per-square-foot ranges by space:
| Space | Per sq ft (HomeAdvisor) |
|---|---|
| Garage | $0.50 to $1.25 |
| Roof | $0.50 to $1.50 |
| Basement | $1.50 to $2.50 |
| Wall | $1 to $4 |
| Attic | $1 to $7 |
Attics have the widest range because they cover everything from a quick blown-in top-up to closed-cell foam sprayed on the underside of the roof deck. Walls cost more per foot than an attic floor when they are already closed, because each stud bay has to be drilled, filled and patched.
Fixr's whole-house figures, installed, give a sense of a full job by home size:
| Home size | Installed (Fixr) |
|---|---|
| 1,000 sq ft | $1,000 to $3,700 |
| 1,500 sq ft | $1,500 to $5,600 |
| 2,000 sq ft | $2,000 to $7,400 |
| 2,500 sq ft | $2,500 to $9,300 |
Bob Vila's attic table runs from $500 to $3,500 for a 500 sq ft attic up to $1,500 to $10,500 for 1,500 sq ft, the spread again being the material. For spray foam specifically, This Old House puts a typical attic at $1,500 to $7,400 and a basement at $1,500 to $5,600.
Doing it yourself is realistic for blown-in attic insulation, with a rented blowing machine and a helper feeding it, and for batts in open walls. HomeAdvisor estimates doing it yourself saves $575 to $750 in labor. Spray foam is a professional job. Whoever does it, wear a respirator, goggles and long sleeves, walk only on joists, and keep insulation away from recessed lights not rated for contact, chimneys and flues.
A worked example: a 1,000 sq ft attic
A two-story home in climate zone 4 has a 1,000 sq ft attic with a thin, patchy layer of old fiberglass that is dirty from a past rodent problem. The owner wants it cleaned out and blown in to the ENERGY STAR level.
- Blown-in insulation. 1,000 sq ft × $0.75 / $1.66 / $2.73 = $750 / $1,658 / $2,730.
- Remove the old insulation. 1,000 sq ft × $1 / $1.25 / $1.50 = $1,000 / $1,250 / $1,500.
- Attic cleaning and prep. $100 / $200 / $300.
- Total. $1,850 to $4,530, with about $3,108 typical at the US average.
The target is R-60, about 16 to 27 inches of blown fiberglass or cellulose depending on the product. If the old insulation had been clean and dry, it could have stayed and the job would be about $1,658 typical. Had the owner chosen open-cell spray foam on the attic floor instead, the insulation line alone would be $2,000 to $5,000, about $3,500 typical, which is why blown-in is the usual choice for attic floors and foam is saved for roof decks, rim joists and walls. Enter a ZIP in the calculator to scale the labor share to your state.
How insulation contractors should price a job
- Quote the R-value. Write the product, the R-value and the settled depth on the estimate, and leave attic rulers or a card at the hatch.
- Price air sealing separately. It is skilled work and the part customers do not see. Show it as its own line.
- Price removal by the bag or the foot. Wet, contaminated or vermiculite insulation is a different job; vermiculite may contain asbestos and needs testing before anyone disturbs it.
- Check the ventilation. Baffles at the eaves keep insulation from blocking soffit vents. Include them.
- Mind the margin. Our profit margin calculator shows the price that keeps it.
The "Save as an estimate" button above turns the result into lines. Send it from Koira and the customer can approve it and pay on their phone.
Last checked October 8, 2026. More for your trade: how remodelers run on Koira.