Attic Insulation Cost Calculator: 2027 Prices Per Sq Ft
See what attic insulation should cost before a contractor quotes you. Enter your attic’s size, pick blown-in fiberglass or cellulose, batts or spray foam, and set the R-value. You get low, mid and high installed prices, labor and material included, for the attic floor alone or the whole attic.
Attic insulation cost in Columbus, OH
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How to Use This Calculator
- Attic Size. Length and width in feet. For the attic floor, that’s usually the footprint of the top story. Leave out the space over an unheated garage unless it’s part of the job.
- Insulation Type. Closed- or open-cell spray foam, fiberglass batts or rolls, or blown-in fiberglass or cellulose.
- Insulation R-Value. Code Minimum fills in R-38 and Maximum fills in R-49. Want R-60? Type it into Needed R-Value.
- Areas to Insulate. Pick “Ceiling Joists Only” to price just the attic floor. “Roof / Walls” prices the rafters too, plus the end walls on a gable roof. It then asks for roof type, slope, framing sizes, windows and skylights, and fills each cavity to full depth, so the framing sets the R-value.
- Location. Prices follow the place shown at the top of the calculator. Click “change” if it’s wrong.
Two switches happen on their own. Pick blown-in and the job drops to the ceiling joists, because loose fill can’t stay put between sloped rafters. Choose “Roof / Walls” with blown-in still selected and the material jumps to closed-cell foam. You can change it to open-cell or batts from there.
What Does Attic Insulation Cost Per Square Foot?
At R-38, budget roughly $1.78 to $2.41 per square foot for blown-in cellulose, $2.47 to $3.36 for blown-in fiberglass and $4.21 to $5.72 for closed-cell foam. Batts and open-cell foam land in between.
Here’s what the calculator returns for an attic floor at R-38, national average, low to high end:
| Attic floor area | Blown-in cellulose | Blown-in fiberglass | Closed-cell foam |
|---|---|---|---|
| 600 sq ft | $1,070 – $1,450 | $1,480 – $2,020 | $2,530 – $3,430 |
| 900 sq ft | $1,600 – $2,170 | $2,220 – $3,020 | $3,790 – $5,150 |
| 1,200 sq ft | $2,130 – $2,890 | $2,960 – $4,030 | $5,050 – $6,860 |
| 1,800 sq ft | $3,190 – $4,330 | $4,440 – $6,040 | $7,570 – $10,290 |
The bill comes down to material, square footage, and how much of the attic gets covered. A cramped space with a tiny hatch slows the crew, and that time lands on the bid even though no calculator can see it. Just need loose fill? Our blown-in insulation calculator goes deeper on that job.
Attic Floor Only, or the Whole Attic?
For most houses, the floor is enough. Heat rises through the ceiling, and a thick layer between the joists slows most of it.
Insulate the roof deck and walls only if the space will be heated or lived in, say after adding headroom with a shed dormer. Doing the walls downstairs too? Our spray foam calculator measures the whole house, subtracts doors and windows, and works out the depth you need.
Attic Insulation FAQ
How much R-value does an attic need?
R-38 is the common minimum, and newer energy codes push colder climates to R-49 or R-60. At R-38 that’s about 10 to 13 inches of batts or loose fill, or roughly 5 1/2 inches of closed-cell foam.
Can an attic have too much insulation?
Yes. Once you reach the R-value your climate calls for, each extra inch saves less than the one before, so the extra money stops paying you back. Worse, piling fill over the soffit vents in a vented attic chokes the airflow and traps moisture. A careful install at the right depth beats a sloppy one at double the thickness.
How much will it cut my energy bills?
ENERGY STAR estimates that air sealing plus added insulation cuts heating and cooling costs by about 15% on average. A bare attic in a cold climate can beat that; one already sitting at R-30 won’t come close. Summers get easier too. Payback is fastest where winters are long and fuel is pricey. Check your current spend with our home heating cost calculator.
Ready to compare bids? Get free quotes from local insulation pros and check them against your estimate.
