calcnet
All calculators

Energy · Cost

Insulation Cost Calculator

Estimate what insulation should cost — by area and material, with or without removing the old stuff. You get a low-to-high installed price range with the insulation, removal, and per-square-foot cost broken out.

Inputs

Attic floor, wall area, or rim-joist run — the surface you're covering.

Result

Adjust the inputs to see your result.

How the estimate works

Insulation is priced per square foot of area covered, installed. The calculator takes the area you're insulating, multiplies by the material's national installed-cost range, adds removal of the old material if you ask for it, and scales the whole thing by your region. The result is an honest low-to-high range, because real insulation bids vary that much.

Each material has its own range: fiberglass batts and blown-in cellulose run about $1–$2.50 per sq ft, mineral wool a touch more, and spray foam the most — open-cell around $1.50–$4 and closed-cell $3–$7. Closed-cell spray foam is pricey but air-seals and packs the highest R-value per inch, so it earns its keep in tight cavities, basements, and rim joists. For an open attic floor, blown-in cellulose is usually the value pick. Most U.S. attics target about R-49, so confirm the installed depth actually hits the R-value for your climate.

What drives the price

  • Material is the biggest lever — closed-cell spray foam can cost 3–4× fiberglass for the same area.
  • Removal of old, wet, or pest-damaged insulation adds roughly $1–$2 per sq ft before the new install even starts.
  • Depth / R-value matters — hitting R-49 in an attic takes more material than a code-minimum top-off.
  • Region swings labor by 40% or more between rural South and coastal metros.

Common mistakes

  • Buying R-value you can't fit. Closed-cell shines in thin cavities; in an open attic, cheaper blown-in gets you to R-49 for less.
  • Skipping air-sealing. Insulation slows heat flow but doesn't stop drafts — caulk and weatherstrip the leaks first.
  • Leaving contaminated insulation in place. Moldy or rodent-soiled material should come out, not get buried under new batts.
  • Taking one bid. Insulation quotes for the same job routinely vary 30–40%. Always get three.

When this calculator is the wrong tool

Use a pro energy audit for: whole-house air-sealing scope, blower-door-verified targets, encapsulated crawlspaces, or insulation tangled up with a moisture or ventilation problem. This tool estimates a standard insulate-by-the-square-foot job. It also doesn't size your HVAC — insulate first, then run the load.

Recommended gear

Recommended for this job

We may earn a commission on qualifying purchases. Prices and availability are set by the vendor.

FAQ

Questions, answered

How much does insulation cost?
Most insulation runs $1–$7 per square foot installed depending on the material. Fiberglass batts and blown-in cellulose are the cheapest at roughly $1–$2.50 per sq ft; closed-cell spray foam is the most expensive at $3–$7 per sq ft. A typical 1,000 sq ft attic floor in fiberglass lands around $1,000–$2,500 installed.
Is spray foam worth it versus fiberglass?
Spray foam costs two to three times more than fiberglass, but it air-seals as it insulates and delivers the highest R-value per inch. Closed-cell is the pick for tight spaces, basements, and rim joists where you can't fit thick batts. For an open, accessible attic floor, blown-in cellulose or fiberglass usually gives more R-value per dollar.
How much insulation does an attic need?
Most of the U.S. targets about R-49 in the attic (roughly 14–18 inches of blown-in or two layers of batts). Colder climates push higher. This calculator prices the area you're covering — check the recommended R-value for your climate zone and confirm the installed depth hits it.
Does removing old insulation cost extra?
Yes. Stripping and disposing of old, wet, or rodent-contaminated insulation adds roughly $1–$2 per square foot on top of the new install. It's worth it when the old material is moldy, matted, or pest-damaged. While you're at it, check for the federal energy-efficiency tax credit, which can offset part of an insulation upgrade.
Is this an exact quote?
No — it's a planning estimate built from national average cost ranges. Insulation prices swing by region, attic access, and depth required. Always get 3 written quotes from licensed local insulation contractors before budgeting.