This insulation cost calculator estimates what it will cost to insulate an attic, wall, roof deck, crawl space or floor. Enter your square footage, climate zone and insulation type to see material, labor and total installed cost, plus the thickness you need to hit your target R-value.
Diagram updates when you calculate. Gray guide lines are 4 in apart; drawing scale caps at 20 in.
Pick where the insulation goes, enter the area and subtract windows, doors or other openings. Choose your climate zone and the tool suggests a target R-value, which you can adjust with the slider. Enter any insulation already in place, then choose a material and whether you or a pro will install it. The result shows total cost, a likely price range, the thickness to install, the amount of material to order and a side-by-side comparison of every insulation type.
Insulation is one of the few home upgrades that pays you back every month. The U.S. Department of Energy estimates that air sealing and adding insulation can cut heating and cooling bills by about 15 percent on average. Contractor quotes for the same attic can differ by $1,500 or more, because they bundle removal, air sealing, and material markup differently. Knowing a realistic number lets you tell a fair quote from an inflated one.
The calculator suits several situations. A homeowner with a 1,200 sq ft attic at R-11 in Atlanta needs to know whether blown-in cellulose at roughly $2.50 per square foot beats fiberglass batts. A buyer budgeting for a 1950s ranch needs to compare closed-cell foam in 2x4 walls against dense-pack cellulose. A landlord insulating a floor over a crawl space wants the cheapest option that meets code. Because the tool also shows the depth each material needs, you can spot when a product will not fit your joists or studs before you buy it.
The tool works out the R-value you still need, converts it to a thickness for each material, then prices that thickness.
Rounding thickness up means the installed R-value always meets or beats your target, never falls short. Application factors raise labor for harder work: walls ×1.3, roof decks ×1.4, crawl spaces ×1.2, floors ×1.15, attics ×1.0. DIY drops labor but adds $75 for rental and protective gear. DIY spray foam kits also cost about 1.6 times bulk rig pricing. Removal runs $1.50 per sq ft for pros and $0.40 DIY, and air sealing runs $0.60 for pros and $0.15 DIY. The likely range is 85% to 125% of the estimate. Suggested targets follow commonly cited values from 2021 IECC Table R402.1.3, using the higher figure where options exist. Local codes vary, so confirm with your building department.
| Material | R per inch | Material $/sq ft/in | Pro labor $/sq ft |
|---|---|---|---|
| Fiberglass batts | 3.2 | 0.11 | 0.40 + 0.05/in |
| Blown-in fiberglass | 2.5 | 0.07 | 0.45 + 0.03/in |
| Blown-in cellulose | 3.5 | 0.08 | 0.45 + 0.03/in |
| Mineral wool batts | 3.8 | 0.30 | 0.50 + 0.05/in |
| Open-cell spray foam | 3.7 | 0.22 | 0.25 + 0.20/in |
| Closed-cell spray foam | 6.5 | 0.55 | 0.25 + 0.40/in |
| Rigid foam board | 5.0 | 0.85 | 0.70 + 0.10/in |
A homeowner in climate zone 3 has a 1,200 sq ft attic floor with R-11 insulation. The suggested target is R-49. They choose professionally installed blown-in cellulose, average local prices, 10% waste and air sealing. These are the tool's default inputs.
Most projects run $1.50 to $4.00 per square foot installed. A 1,200 sq ft attic with blown-in insulation typically costs $1,800 to $3,900. Wall retrofits and spray foam cost more because the labor is harder.
The 2021 IECC calls for roughly R-30 in zone 1, R-49 in zones 2 and 3, and R-60 in zones 4 through 8. Your local code may differ, so check with your building department.
For attic floors, blown-in cellulose and fiberglass are usually cheaper per R-value and fill gaps better. Batts can be cheaper for DIY work in standard-depth wall cavities. Use the comparison table to see both for your numbers.
Batts and attic loose-fill are common DIY jobs if you wear a respirator, goggles and gloves. Spray foam and dense-pack wall work are best left to professionals. Foam needs proper ventilation, and loose-fill in walls needs special equipment.
Rounding up to the next half inch means the installed R-value meets or exceeds your target. It costs slightly more but keeps you on the safe side of code minimums.
Yes, in most cases. The IRC (section R316) generally requires foam plastics in living spaces to be covered by a thermal barrier such as half-inch drywall. Attics and crawl spaces can have different rules, so ask your inspector.
Estimates use typical U.S. pricing and are for planning only. This is not engineering advice, a permit or inspection approval, or a statement of code compliance. Local codes and prices vary.
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