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Attic Insulation Cost Calculator

Estimate 2026 attic insulation cost in USD across blown cellulose, fibreglass, batts and mineral wool with material, labor and IECC climate-zone totals.

Attic Insulation Cost Calculator

Estimate material, labour and total cost to top up attic insulation. Pricing reflects 2026 US averages from contractor bid databases.

Total installed cost
$2,500
Cost per sq ft: $2
Material cost
$700
50 × $14
Labour cost
$1,800
Reference standard
IECC 2021
Sources: Angi 2026, HomeAdvisor, NRCA

What this calculator does

This tool estimates the total installed cost of an attic insulation top-up in 2026 US dollars, broken into material and labour. It uses 2026 contractor-bid averages from Angi, HomeAdvisor, and the National Roofing Contractors Association (NRCA) cost benchmark survey, adjusted for region, access difficulty, and material choice.

Enter your attic floor area, the target R-value for your IECC climate zone, the existing R-value, the insulation type, and how easy the attic is to access. The calculator returns the material cost, labour cost, total installed cost, and the cost per square foot so you can compare quotes.

How the cost math works

Total cost is the sum of two lines:

  1. Material cost = bag count × bag price. Bag count is derived from the manufacturer’s coverage table at the depth needed to fill the R-gap (target R minus existing R). A 19-pound bag of GreenFiber Cocoon-R cellulose covers 30 sq ft at R-30; at R-49 it covers 30 × 30/49 ≈ 18 sq ft. Bag price is set at the 2026 Home Depot, Lowe’s, and Menards average: $14 for blown cellulose, $19 for blown fibreglass, $38 for R-30 fibreglass batts, $42 for mineral wool batts.
  2. Labour cost = area × labour rate × access multiplier. The 2026 baseline labour rate from the NRCA blown-insulation database is $1.20 per sq ft for normal-access top-ups. Easy walk-up attics get a 0.85 multiplier; difficult or restricted attics get 1.40.

The two lines combine to give a total installed estimate. National averages from the 2026 Angi cost-of-services index put a 1,500 sq ft top-up at $1,800 to $2,800 installed — the calculator output sits in the same band when you use the default inputs.

Material cost breakdown by insulation type

Insulation2026 bag/bundle priceCoverage at R-30$/sq ft material at R-49
Blown cellulose (GreenFiber, Applegate)$1430 sq ft$0.46
Blown fibreglass (Owens Corning AttiCat)$1942 sq ft$0.44
R-30 fibreglass batt (Owens Corning, Johns Manville)$38 / 75 sq ft bundle75 sq ft$0.51
Mineral wool R-30 batt (Roxul Comfortbatt)$42 / 60 sq ft bundle60 sq ft$0.70

Mineral wool batts cost more per square foot but bring fire resistance, rodent resistance, and dimensional stability that cellulose can’t match. For tight-to-eaves jobs or attics with significant rodent history, the price premium is usually justified.

Labour cost benchmarks

NRCA 2026 contractor-bid data shows three distinct labour bands:

  • Easy walk-up attic, no obstructions: $0.95 to $1.10 per sq ft
  • Normal pull-down ladder access, average pitch: $1.20 to $1.50 per sq ft
  • Difficult: knee walls, low pitch, HVAC obstructions: $1.65 to $2.20 per sq ft

Regional variation is real but smaller than people assume. The Pacific Northwest, Mountain West, and Northeast typically run 8 to 15 percent higher than the Mid-Atlantic baseline; the Southeast and Texas run 5 to 10 percent lower. The biggest single driver of labour cost is not region — it’s whether the contract includes air-sealing as a separate line.

Air-sealing — the line that decides ROI

The Department of Energy’s 2024 Building America field study repeated what NRCA has been saying for two decades: pairing R-30 of insulation with proper top-plate caulking outperforms R-60 of unsealed insulation in 84 percent of measured homes. If the air-seal package is in the bid, expect to pay $0.45 to $0.85 per sq ft on top of the insulation line. If it’s not, ask why.

The air-seal package should hit:

  1. Top plates of every interior wall, caulked or low-expansion-foamed.
  2. Recessed lights — replace with airtight IC-rated LED retrofits or build a fire-rated dam.
  3. Duct boots, plenum joints, and HVAC penetrations sealed with mastic.
  4. Plumbing stacks, electrical conduits, and bathroom-fan housings foamed at the deck penetration.
  5. Attic hatch replaced with an insulated, weatherstripped lid (typically $120 to $180 in materials).
  6. Soffit baffles installed before loose-fill is blown to maintain ventilation gap.

Skip these and you’ll lose 20 to 30 percent of your effective R-value to convective bypass, regardless of how much insulation you buy.

Federal and state incentives in 2026

The Section 25C Energy Efficient Home Improvement Credit was extended by the Inflation Reduction Act through 2032 and refunds 30 percent of insulation material cost up to a $1,200 annual cap. Labour does not qualify but materials do. Save your receipts, the manufacturer’s NRCA-listed product number, and IRS Form 5695 for filing.

HEEHRA (High-Efficiency Electric Home Rebate Act) rebates run up to $1,600 for insulation in households at or below 150 percent of area median income. Implementation is state-level; check your state energy office’s HEEHRA program page. The DSIRE database (dsireusa.org) lists every state and utility rebate currently active for residential insulation.

Many investor-owned utilities run on-bill rebates: Pacific Power, Eversource, ConEd, and FPL all currently offer $0.50 to $1.00 per sq ft for blown-insulation top-ups verified by a Building Performance Institute (BPI) auditor. Some require a pre-job energy audit ($200 to $400, often free under utility programs); the audit pays for itself if it qualifies you for the rebate stack.

Climate zone cost adjustments

The IECC 2021 attic minimums set the target R-value, which directly drives bag count and total cost:

  • Zone 1 to 2 (Florida, southern Texas, Hawaii): target R-30 — about 30 percent fewer bags than the calculator default
  • Zone 3 to 5 (most of the southern, central, and Mid-Atlantic US): target R-49 — calculator default
  • Zone 6 to 8 (northern New England, Upper Midwest, Mountain West, Alaska): target R-60 — about 22 percent more bags

A Boise (Zone 5) and a Burlington Vermont (Zone 6) attic at the same square footage will see total cost diverge by roughly $400 to $700, almost entirely driven by the extra material at R-60.

Comparing contractor quotes

A clean attic-insulation quote in 2026 should break out four lines: removal of old insulation if needed, air-sealing scope, baffle and dam-around installation, and the new insulation itself with R-value and material specified. If a contractor gives you a single all-in number with no R-value commitment in writing, ask for an itemised re-quote. The 2026 Angi data shows that contractors who refuse to itemise air-sealing tend to underdeliver on the air-seal — and the energy savings disappear with it.

Pricing red flags: bids more than 30 percent below the regional median (suggesting the contractor will skip air-sealing or use a non-NRCA-listed material), bids that don’t specify final R-value, and bids that quote inches of depth rather than R-value (depth is meaningless without product specification). Bids more than 25 percent above the regional median should come with a documented justification — extensive structural work, hazmat removal, or a premium product like JM Spider Plus blown fibreglass.

Frequently asked questions

How much does attic insulation cost in 2026?
For a 1,500 sq ft attic, expect $1,800 to $2,800 installed for a blown-cellulose top-up from R-19 to R-49, or $2,400 to $3,600 for blown fibreglass. The 2026 national average from Angi and HomeAdvisor sits at $1.75 to $2.10 per square foot all-in, with material running 30 to 40 percent of that and labour the remaining 60 to 70 percent. Climate Zone 6 to 8 jobs targeting R-60 add roughly $0.40 per square foot. Tight or cut-up attics with knee walls run another 25 to 40 percent over the easy-access baseline.
What costs more: blown cellulose, fibreglass, or batts?
Per square foot installed, blown cellulose is typically the cheapest at $1.20 to $1.50, followed by blown fibreglass at $1.40 to $1.85, fibreglass batts at $1.60 to $2.20, and mineral wool batts at $1.90 to $2.60. Cellulose wins on R-per-dollar because of higher R-per-inch (3.5 vs 2.5 for fibreglass) and lower bag pricing. Batts cost more per square foot installed because each cavity has to be hand-cut and friction-fit between joists, which is labour-intensive in cluttered attics.
Does access difficulty really affect the price that much?
Yes. Easy walk-up attics with floored decking and full headroom typically cut labour by 15 percent. Difficult attics with low pitch, no decking, knee walls, or HVAC equipment sprawled across the floor typically add 35 to 45 percent to the labour line. The reason is simple: installers spend more time clearing obstructions and air-sealing penetrations than blowing the actual material. Insurance and worker's-comp loadings also climb when crews are working in restricted spaces.
Are there 2026 federal tax credits for attic insulation?
Yes. The Section 25C Energy Efficient Home Improvement Credit, extended through 2032 by the Inflation Reduction Act, returns 30 percent of insulation material cost up to $1,200 per year. Labour does not qualify, but materials including bags, batts, weatherstripping and air-sealing foam do. State and utility rebates layer on top: most large investor-owned utilities offer $0.50 to $1.00 per square foot for verified blown-insulation top-ups, and Department of Energy HEEHRA rebates can add up to $1,600 for households below 150 percent of area median income.
Should I get a contractor or DIY?
DIY attic top-ups are realistic for 1,200 to 2,000 sq ft single-storey attics with easy access. Big-box stores rent the blower for free with a 10-bag minimum purchase, so material-only cost runs $700 to $900 versus $1,800 to $2,800 contractor-installed. The trade-off is air-sealing: a contractor will typically caulk top plates, foam penetrations, and replace non-IC-rated cans before blowing, and that air-seal work is what delivers the actual energy savings. If you skip air-sealing, the DIY cost-per-saved-BTU stops looking like a bargain.
How long does the installation take?
A two-person professional crew typically completes a 1,500 sq ft top-up in 3 to 5 hours, including baffles, dam-around-cans, and depth markers. Add 1 to 2 hours for air-sealing if it's part of the contract. DIY with a rented blower runs 5 to 8 hours for the same job. Cathedral ceilings, dense-pack walls, or removal of contaminated existing insulation push the timeline to a full day or two days. Same-day jobs are routine for permit-exempt top-ups in jurisdictions that don't require an inspection.
Does the cost include removing old insulation?
Usually not. Removal is typically a separate $1.00 to $2.00 per square foot line item, and runs higher if the old insulation is contaminated with rodent waste, asbestos-suspect vermiculite (Libby-source Zonolite), or fire damage. For clean fibreglass batts that are simply tired, contractors will normally over-blow rather than remove, which keeps the project price down. Plan for removal only if there's a specific reason — moisture damage, contamination, or a deck repair underneath.
How much does it cost to insulate a 2,000 sq ft attic?
At 2026 rates, a 2,000 sq ft attic top-up from R-19 to R-49 with blown cellulose runs $2,400 to $3,800 installed. The same job with blown fibreglass runs $2,800 to $4,400, and with R-30 fibreglass batts $3,200 to $4,800. Climate Zone 6+ jobs targeting R-60 add about $600 to $900 to the upper-end estimate. The federal tax credit at 30 percent of material can return $250 to $400 of that, and utility rebates can knock another $1,000 to $2,000 off if your utility runs an active program.

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