Skip to content
ARMORTHANE PROTECTING YOUR WORLD

PROTECTING YOUR WORLD

ARMORTHANE PROTECTING YOUR WORLD

Blown-In Insulation:
Cost, R-Value &
Fiberglass vs Cellulose

What blown-in attic insulation costs in 2026, how fiberglass, cellulose and rockwool compare on real bag charts, and calculators for depth, bags and payback.
Attic Insulation Quotes

Blown-in on the floor or foam on the roof? Get an honest answer.

Tell us the attic size, where the furnace and ducts are, and what insulation is there now. We will connect you with a certified applicator for spray foam where it fits.

  • Attic floor area and access
  • HVAC equipment in the attic?
  • Existing insulation depth
  • Ice dams, hot rooms or drafts
Rather talk now? Call (417) 831-5090
Step 1 of 3
$1.00–$2.80
Blown-in insulation per sq ft, installed
HomeGuide, 2026
R-49–R-60
DOE target for an uninsulated attic, zones 2–6
energy.gov
15%
Average heating and cooling savings from air sealing plus insulating
EPA ENERGY STAR
30%
Loss in loose fiberglass effectiveness below about 0°F attic temperature
ORNL, 1991

Blown-in insulation is loose fiber, usually fiberglass, cellulose or rockwool, that a machine blows through a hose onto an attic floor or into closed wall cavities. On an open attic floor it is the cheapest way we know to get to R-49 or R-60, and it fills around wires, trusses and odd framing that batts never fit. We manufacture spray foam, and on most vented attics we still tell homeowners that blown-in insulation over a sealed ceiling is the better buy. This guide compares the three blown-in materials with real bag-chart numbers, shows 2026 costs, explains what separates a good install from a bad one, and gives you two calculators: one for bags and depth, one for savings and payback.

Quick answer

Blown-in insulation costs $1.00 to $2.80 per square foot installed (HomeGuide, 2026), and an average attic job runs $900 to $3,600. Fiberglass is lightest and settles least but needs about 17 inches for R-49; cellulose needs about 15 inches installed for R-49 and slows air better, but weighs more than twice as much; rockwool costs the most and is noncombustible. Air seal the attic floor first: EPA's average 15% heating and cooling savings assumes both air sealing and insulation. If your ductwork or furnace is in the attic, or there is no attic at all, spray foam at the roof deck is usually the better approach.

What's in this guide
  1. 1Blown-in insulation materials
  2. 2Fiberglass vs cellulose vs rockwool
  3. 3Blown-in attic calculator
  4. 4Blown-in insulation cost
  5. 5Savings and payback by climate zone
  6. 6How to get a good install
  7. 7FAQ
Materials

Blown-in insulation materials

DOE groups these under loose-fill insulation: small pieces of fiber blown into place with special equipment, which makes them good for adding insulation to existing finished areas, odd-shaped spaces and around obstructions.

Most common

Blown fiberglass

Chopped glass fiber, about R-2.2 to R-2.9 per inch. Light, does not absorb water, and settles little. Owens Corning's AttiCat chart calls for 17 inches and 25 bags per 1,000 sq ft for R-49, at 0.69 lb per square foot.

Best value per inch

Blown cellulose

Recycled paper with fire retardants, about R-3.6 per inch on average (CIMA). Denser, so it resists wind-washing and convection, but settles up to 20%. GreenFiber's chart calls for 15 inches installed (13.5 settled) for R-49. Full details in our cellulose insulation guide.

Fire resistant

Blown rockwool

Stone wool fiber, R-3.2 to R-4.1 per inch per HomeGuide, noncombustible, and the most expensive of the three at $1.90 to $4.20 per sq ft installed. Our mineral wool guide covers the material in depth.

Side by side

Blown-in fiberglass vs cellulose vs rockwool

Bag charts are the honest way to compare blown-in materials, because they tell you the depth, bag count and weight a manufacturer will stand behind for each R-value. Sort any column.

MaterialR per inchInstalled $ / sq ftDepth for R-49Weight at R-49 (lb/sq ft)SettlingCombustible?
Fiberglass (AttiCat)R-2.2 to R-2.9$1.00–$2.8017 in0.69Less than celluloseNo
Cellulose (GreenFiber)R-3.1 to R-3.8$1.20–$2.8015 in (13.5 settled)1.80Up to 20%Treated, passes CPSC test
RockwoolR-3.2 to R-4.1$1.90–$4.20Per product chartPer product chartLess than celluloseNo
Sources: Owens Corning AttiCat manufacturer's fact sheet; GreenFiber loose-fill cellulose coverage chart; HomeGuide blown-in insulation cost 2026 (R per inch, installed prices); Fine Homebuilding/GBA (cellulose settling); 16 CFR 1209 (cellulose fire standard).

Which one should go in your attic?

  • Cold climate, older house with lots of small leaks: cellulose. Its density slows air movement, and Oak Ridge National Laboratory found convection cut loose fiberglass effectiveness by 30% in attics below about 0°F.
  • Weak or sagging ceiling, or a leak-prone roof: fiberglass. At R-60 it weighs 0.87 lb per square foot against 2.26 for cellulose, and it does not hold water.
  • Fire resistance matters most: rockwool, which is noncombustible, if you can find an installer and accept the price.
  • Ducts or furnace in the attic: consider moving the insulation to the roof deck with spray foam instead; see attic foam insulation.
Calculator

Blown-in attic insulation calculator

Enter the attic floor area and what is up there now. The calculator works out how much R-value you are missing, then shows depth, bags, weight and installed cost for both fiberglass and cellulose using the manufacturers' own coverage charts.

Bags and depth

How much blown-in insulation do I need?

Existing R = depth x R per inch (batts 3.2, blown fiberglass 2.5, cellulose 3.2). Depth, bags and weight for the R you add are interpolated from the AttiCat chart (27.5 lb bags) and GreenFiber chart (22.55 lb bags). Cost scales HomeGuide's 2026 prices of $660 to $1,200 per 1,000 sq ft for R-30 and $1,400 to $2,400 for R-60.

Material to add
—
R-value to add
—
Depth to blow
—
Bags
—
Installed cost range

Use the bag count on the actual product you buy; every product's chart is different, and the FTC's R-Value Rule ties the R-value claim to installing at least the labeled number of bags at the labeled thickness. For a cellulose-only deep dive, including dense-packing walls, see our cellulose insulation guide.

2026 pricing

Blown-in insulation cost

HomeGuide's 2026 national figures are the most detailed public numbers we know of. Your local price depends mostly on attic access, how much air sealing is included, and whether old insulation has to come out first.

Per sq ft

$1.00 to $2.80 installed

The typical range for blown-in attic insulation; the full spread runs from about $0.50 to over $5.00. Fiberglass material alone is $0.30 to $1.10 per sq ft and cellulose $0.30 to $1.80.

By R-value

R-30 vs R-60

Per 1,000 sq ft of attic floor: R-30 runs $660 to $1,200 and R-60 runs $1,400 to $2,400. Most attics land at $900 to $3,600 in total.

Add-ons

Removal and labor

Removing old insulation adds $1 to $2 per sq ft. Labor runs $40 to $80 per hour, and a blowing machine rents for $100 to $200 a day if you do it yourself.

Walls

Dense-pack retrofits

Blowing exterior walls costs $1,900 to $7,800 for a typical house, or $1,600 to $4,200 per 1,000 sq ft of wall for dense-pack cellulose.

For context, closed-cell spray foam material alone runs about $0.90 to $1.00 per board foot (HomeGuide), so foaming a roof deck to R-49 costs several times what blowing R-49 on the floor does. That is why we only recommend roof-deck foam when there is a reason: HVAC in the attic, a cathedral ceiling, or a room-over-garage that never gets comfortable. Our attic insulation cost guide runs the numbers on both approaches, and spray foam insulation cost covers foam pricing in detail.

Calculator

Savings and payback by climate zone

Pick your climate zone and enter what you spend a year on heating and cooling. The estimate uses EPA ENERGY STAR's modeled savings for air sealing plus insulating to 2012 IECC levels, which is about what a good blown-in attic job delivers when the ceiling is sealed first.

Payback

What will blown-in insulation save me?

Annual savings = heating and cooling cost x EPA's heating and cooling savings percentage for your zone (7% in zone 1 up to 20% in zone 4C). Payback = project cost / annual savings. DOE attic targets are for an uninsulated attic.

From your utility bills
Use the calculator above or your quote
—
Estimated savings per year
—
Simple payback
—
DOE attic target

Process

How to get a good blown-in insulation install

Most of the difference between a blown-in job that works and one that does not happens before the hose comes out. Whether you hire it out or rent the machine, this is the order of work.

  1. Inspect and fix the roof and vents first

    Look for roof leaks, bath or kitchen fans venting into the attic, and damp or moldy sheathing. Fans must exhaust outdoors. Insulation will not fix a moisture problem and will hide it.

  2. Air seal the attic floor

    Seal top plates, plumbing and wiring holes, recessed lights, chases and the hatch. Use fire-rated sealant around flues. This is where much of the comfort and savings comes from.

  3. Baffles, dams and clearances

    Install baffles at every rafter bay over the soffits so insulation does not block intake ventilation, dam the hatch, and keep required clearances around chimneys and non-IC-rated fixtures.

  4. Mark the depth

    Staple depth rulers across the attic, set to the installed thickness on the bag chart for your R-value.

  5. Blow evenly and count bags

    Work from the far eaves back to the hatch, keep the hose low for an even layer, and use at least the chart's bag count for the area. Then get the FTC-required receipt showing area, installed and settled thickness, R-value and bags used.

When blown-in is not the answer

Blown-in insulation assumes a vented attic with a reasonably flat floor. It is the wrong tool for cathedral ceilings and low-slope roofs with no attic (see cathedral ceiling insulation), for rim joists and crawl spaces, and for attics that hold the furnace and ducts, where moving the insulation and air seal to the roof deck with spray foam keeps that equipment inside the conditioned space. For closed walls, dense-pack cellulose is the blown option and injection foam is the alternative.

Attic insulation quotes

Furnace or ducts in the attic? Get a roof-deck foam quote.

Tell us the attic size, where the HVAC equipment sits and what insulation is there now. A certified ArmorThane applicator can quote spray foam for the roof deck, and will tell you if blown-in on the floor is the better buy for your house.

Get a free quoteFind an applicator

Contractors: become an applicator →

FAQ

Blown-in insulation: common questions

How much does blown-in insulation cost?

HomeGuide's 2026 range is $1.00 to $2.80 per square foot installed, with most attic jobs between $900 and $3,600. By R-value, R-30 runs $660 to $1,200 and R-60 runs $1,400 to $2,400 per 1,000 square feet of attic floor. Removing old insulation adds $1 to $2 per square foot.

Is blown-in insulation better than batts?

On an attic floor, usually yes. Blown-in fills around wiring, truss webs and irregular joists without the gaps and compression that batts leave, and it is easy to reach R-49 or R-60 in one layer. Batts are better in open stud walls and floors, where blown loose-fill has nothing to hold it in place.

Is blown-in fiberglass or cellulose better?

Cellulose has more R per inch (about R-3.6 versus R-2.2 to R-2.9), resists convection losses in very cold attics and slows air movement better. Fiberglass weighs much less (0.69 versus 1.80 lb per sq ft at R-49 on the AttiCat and GreenFiber charts), settles less and does not absorb water. Installed prices are similar.

How deep should blown-in insulation be?

It depends on the material and the target R-value. For R-49, Owens Corning's AttiCat fiberglass chart calls for at least 17 inches and GreenFiber cellulose about 15 inches installed (13.5 inches settled). For R-60 the figures are 20.5 inches of fiberglass and 18.3 inches of cellulose. DOE notes that if you have less than about R-30, roughly 10 to 13 inches, you could probably benefit from adding more.

Can I blow in insulation myself?

Yes, on an accessible attic floor. HomeGuide lists machine rental at $100 to $200 per day. Two people make it far easier: one feeding bags, one on the hose. Do the air sealing, baffles and hatch dam first, wear a respirator, and follow the bag chart. Dense-packing walls takes a more powerful machine and experience.

Does blown-in insulation settle?

Cellulose settles up to 20% in the months after installation, which is why its charts list an installed and a minimum settled thickness. Blown fiberglass settles less. In both cases, installing to the chart's initial thickness with the full bag count delivers the labeled R-value.

Can you blow insulation over existing insulation?

Yes, as long as the existing insulation is dry and clean. The R-values add together. Pull out anything wet, moldy or contaminated by rodents first, and do not cover the soffit vents or recessed lights that are not rated for insulation contact.

How much will blown-in insulation save on energy bills?

EPA ENERGY STAR estimates homeowners save an average of 15% on heating and cooling costs, about 11% of total energy costs, by air sealing and adding insulation, modeled to 2012 IECC levels with a 25% cut in air leakage. The range runs from 7% of heating and cooling in climate zone 1 to 20% in zone 4C.

Related guides

Other insulation types, compared honestly

Loose-fill

Cellulose insulation

Attic and dense-pack wall cellulose, settling, fire treatment and bag math.

Overview

Types of insulation

Every major insulation type compared, with a thickness calculator and a selector.

Batts and board

Mineral wool insulation

Stone wool for fire, sound and continuous insulation, with a wall checker.

Rigid board

Foam board insulation

EPS vs XPS vs polyiso for foundations, slabs and exterior walls.

AT
Written by the ArmorThane technical team. We have manufactured spray foam, polyurea and protective coatings in Springfield, Missouri since 1989; our applicators insulate attics both ways, at the roof deck with foam and on the floor alongside blown-in installers. Figures are from the sources below. Updated October 2026.

Sources

  1. HomeGuide, Blown-in insulation cost (2026): homeguide.com
  2. HomeGuide, Insulation cost (2026): homeguide.com
  3. Owens Corning, AttiCat manufacturer's fact sheet and coverage chart: owenscorning.com (cloudfront)
  4. GreenFiber, loose-fill cellulose fact sheet and coverage chart: homedepot.com
  5. U.S. DOE Energy Saver, Insulation (recommended attic R-values) and Where to Insulate: energy.gov, energy.gov
  6. U.S. DOE Energy Saver, Types of Insulation (loose-fill): energy.gov
  7. EPA ENERGY STAR, air sealing and insulation savings methodology (savings by climate zone): energystar.gov
  8. Fine Homebuilding via Green Building Advisor, Blown insulation for attics (ORNL 1991 convection finding, settling): greenbuildingadvisor.com
  9. Cellulose Insulation Manufacturers Association, homeowner facts: cellulose.org
  10. FTC R-Value Rule, 16 CFR 460.17 installer receipts: ecfr.gov
  11. U.S. CPSC, 16 CFR Part 1209 cellulose insulation standard: ecfr.gov

latest news & bLOGS

Learn more

Attics insulated the right way.

Homeowners get a certified ArmorThane applicator who will say when blown-in is the better buy and when the roof deck needs foam. Contractors can add spray foam with no franchise fee and no royalties.

Find an applicator →Become an applicator
United States 417-831-5090 · Canada 780-444-6200

CONTACT US

REQUEST A QUOTE OR

BECOME AN APPLICATOR

ArmorThane has built a strong reputation over the past 30 years for producing high-quality, durable protective coatings.

group 115 660555abebfe4
Phone Number

Tel: 417.831.5090

group 115 1 660556c21395c
Email Us

moreinfo@armorthane.com

Step 1 of 3

We want to help you find the best ArmorThane applicator for your protective coating project. Please either fill out the request form below or call us toll free at 417-831-5090, any time Monday-Friday, 8:00 a.m. to 5:00 p.m. Central Standard Time.

RV Find An Applicator

Step 1 of 3

Connect with an authorized ArmorThane professional to get a long-lasting, seamless protective coating for your RV. Submit the form below or call us directly at 417-831-5090 (Monday–Friday, 8:00 AM – 5:00 PM CST).

Facebook Twitter Youtube

Find An Applicator

Applicator Login

Armorthane Logo Outlined
CALL NOW
BECOME APPLICATOR
FIND APPLICATOR

Protective Coating Applications

Products

Applicator Opportunities

Knowledge Center

Galleries