Ashburn, VA

How much does blown-in insulation cost?

$1.00 – $2.80 cost per square foot
$900 – $3,600 average total cost for attic

Get free estimates from insulation contractors near you, or view our cost guide below.

March 15, 2022

Reviewed by Tom Grupa and 3 expert insulation installers on HomeGuide.

Blown-in insulation cost

Blown-in insulation costs $1.00 to $2.80 per square foot, depending on the type, location, R-value, and whether it's cellulose, fiberglass, or Rockwool. Blown-in attic insulation costs $900 to $3,600 on average. Blown-in wall insulation costs $1,900 to $7,800 for a home's exterior walls.

Blown-in insulation cost
Location Average cost*
Attic floor $900 – $3,600
Exterior walls $1,900 – $7,800
2-car garage $1,400 – $4,600
Garage walls $950 – $3,200
Garage attic floor $520 – $1,400
Entire house (new construction) $3,500 – $11,600
Entire house (existing construction) $4,500 – $16,000

*Based on a 2,000 to 2,500 SF home with a 2-car detached garage.

Blown-in insulation cost per square foot

Blown-in insulation costs $1.00 to $2.80 per square foot on average. Blown-in insulation prices range from $0.50 to $5.00 per square foot or more, depending on the type, R-value, and project location and size.

Blown-in insulation cost per square foot
Square feet Average cost to install
100 $100 – $280
300 $300 – $840
500 $500 – $1,400
700 $700 – $2,000
1,000 $1,000 – $2,800
1,200 $1,200 – $3,400
1,500 $1,500 – $4,200
2,000 $2,000 – $5,600
2,500 $2,500 – $7,000
3,000 $3,000 – $8,400

Average cost of blown-in insulation

The following table shows the cost of installing blown-in insulation for an average project:

Blown-in insulation cost - chart
Blown-in insulation cost - chart

Average cost of blown-in insulation
National average cost $1,900
Minimum cost $500
Maximum cost $9,000
Average cost range $800 to $3,000

Cost data is from research and project costs reported by HomeGuide members.

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Blown-in attic insulation cost

Blown-in attic insulation costs $0.90 to $2.40 per square foot or $900 to $3,600 on average. Blown-in insulation is preferred in attics because it easily fills gaps, joints, and hard-to-access areas. Insulating an attic lowers energy bills, improves indoor air quality, and stabilizes indoor temperatures.

Blown-in attic insulation cost
Square footage Bags needed Material cost Total cost installed
1,000 14 – 32 $420 – $1,300 $900 – $2,400
1,200 17 – 38 $510 – $1,500 $1,100 – $2,900
1,500 21 – 48 $630 – $1,900 $1,350 – $3,600
1,800 25 – 58 $750 – $2,300 $1,600 – $4,300
Blown-in attic insulation cost by R-value
R-value Bags per 1,000 SF Material cost Minimum thickness Labor hours Total cost per 1,000 SF
R-30 14 – 15 $420 – $600 10.25″ 6.0 – 7.0 $660 – $1,200
R-38 18 – 20 $540 – $800 13.00″ 7.5 – 8.5 $840 – $1,500
R-44 21 – 23 $630 – $920 15.00″ 9.0 – 9.5 $990 – $1,700
R-49 24 – 26 $720 – $1,000 16.50″ 10.0 – 11.0 $1,100 – $1,900
R-60 29 – 32 $870 – $1,300 20.00″ 12.0 –13.5 $1,400 – $2,400
  • The minimum recommended R-value for attic insulation is R-30 to R-60, depending on the geographical location.
  • Some companies have a $1,500 to $2,000 minimum project requirement.
  • Multiple fixtures requiring dams and air sealing increase the cost.
  • Installation takes 2 to 4 days with a two-person crew.

Blown-in fiberglass insulation in attic
Blown-in fiberglass insulation in attic

Blown-in wall insulation cost

Blown-in wall insulation costs $1.10 to $3.70 per square foot or $1,900 to $7,800 to insulate all exterior walls. The insulation type, number of walls, and whether the insulation is installed from the interior or exterior impact the total.

Blown-in wall insulation cost
R-value Bags per 1,000 SF Material cost Installed thickness Labor hours Total cost per 1,000 SF installed
R-13 10 – 20 $300 – $800 3.5″ 20 $1,100 – $2,400
R-15 15 – 22 $450 – $880 3.5″ 23 $1,400 – $2,700
R-21 21 – 28 $630 – $1,100 5.5″ 27 $1,700 – $3,300
R-23 26 – 35 $780 – $1,400 5.5″ 30 $2,000 – $3,800
  • The minimum recommended R-value for wall insulation is R-13 to R-21, depending on the home's region and wall framing.
  • 2x4 wall framing fits up to R-15 insulation with a 3.5-inch thickness.
  • 2x6 wall framing fits up to R-23 insulation with a 5.5-inch thickness.

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Blown-in insulation cost calculator by type

Blown-in insulation cost depends on the material, R-value, project size, and location:

Blown-in insulation cost calculator
Insulation type Material cost per square foot Installed cost per square foot Features
Fiberglass $0.30 – $1.10 $1.00 – $2.80
  • Budget-friendly
  • R-value 2.2 – 2.9 per inch
  • Not flammable
  • Low dust during installation
  • Little or no settling
Cellulose $0.30 – $1.80 $1.20 – $2.80
  • R-value 3.1 – 3.8 per inch
  • Eco-friendly; made from recycled newspaper
  • Flammable; treated with fire-retardant
  • Settles 10% after installation
Rockwool $1.20 – $2.50 $1.90 – $4.20
  • R-value 3.2 – 4.1 per inch
  • Superior sound dampening
  • Not widely available
  • Professional installation recommended

Blown-in cellulose insulation
Blown-in cellulose insulation

Blown cellulose insulation cost

Blown cellulose insulation costs $0.60 to $4.20 per square foot with installation, depending on the type and project size. Cellulose's 3.1 to 3.8 per inch R-value provides a better thermal barrier than fiberglass. Cellulose is also eco-friendly, made of primarily recycled newspaper.

Blown cellulose insulation cost
Material Cost per square foot installed Project sustainability
Wet-spray cellulose $0.60 – $2.00 New construction
Dense-pack cellulose $1.60 – $4.20 Remodeling
  • Cellulose's settling characteristic is beneficial in colder climates because it creates a denser, more effective thermal barrier than fluffier, loose-fill fiberglass.
  • Some experts recommend against cellulose insulation in fire-prone regions because the core material is still highly flammable even though it is treated with fire retardants.

Wet cellulose insulation cost

Wet cellulose insulation costs $0.60 to $2.00 per square foot, including installation. Wet-spray or damp-spray insulation is loose-fill cellulose, fire retardant, water, and adhesive sprayed into wall cavities before covering with drywall. Wet cellulose insulation works best for new construction.

Dense-pack cellulose cost

Dense-pack cellulose costs $1.60 to $4.20 per square foot or $1,600 to $4,200 to insulate 1,000 square feet of wall space. Dense-pack insulation is ideal for older homes and exterior walls.

Hire a professional or measure and weigh before installing dense-pack insulation to ensure the density reaches 3.5 pounds per cubic foot.

Blown-in fiberglass insulation cost

Blown-in fiberglass insulation costs $1.00 to $2.80 per square foot on average. A bag of fiberglass insulation costs $30 to $40. Loose-fill fiberglass is naturally fire- and moisture-resistant, does not settle, and weighs less than cellulose.

Wearing personal protective equipment (PPE) is essential when handling fiberglass. Fiberglass can cause skin irritation if touched and lung damage if inhaled.

Rockwool blown insulation cost

Rockwool blown insulation costs $1.90 to $4.20 per square foot on average with installation. Blown-in Rockwool is costlier and not as widely available as cellulose and fiberglass but offers natural fire and water resistance, a high R-value, and superior sound dampening.

Companies often use "Rockwool" and "mineral wool" interchangeably. Rockwool is a brand of mineral or stone wool made of basalt and recycled steel slag, melted and spun into fibers resembling sheep's wool.

Mineral wool insulation is harmless once installed but inhaling it during installation is dangerous. Always hire a professional.

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Blown-in insulation installation pricing factors

Several factors affect blown-in insulation pricing:

  • Location size and access – The larger the area being insulated, the more materials and time are required.
  • Insulation type, R-value, and thickness – Higher R-value insulation typically costs more. More depth and thicker layers require more material.
  • Air sealing between the attic and living space costs $350 to $3,000, depending on ductwork, fans, and ceiling fixtures. Some contractors include air sealing in the estimate.
  • Current insulation – A home with existing insulation that has settled but is still in good shape requires less insulation than a house needing complete replacement.
  • Old insulation removal and disposal costs $1 to $2 per square foot.
  • Installing a roof vent costs $200 to $700. Any vents exhausting air from the home into the attic must be vented outside before installing blown-in insulation.
  • Attic cleaning costs $100 to $600 or more.
  • Attic mold removal costs $1,500 to $3,500 or more, depending on the damage.
  • Asbestos removal costs $20 to $65 per square foot. Asbestos testing costs $250 to $750.
  • A pest inspection costs $40 to $150. Pest extermination costs $135 to $200 per visit.
  • Drywall repair costs $100 to $400 per hole. Insulating existing walls requires drilling holes in the interior drywall or exterior sheathing.
  • Electricians charge $40 to $100 per hour to fix damaged wiring.
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Blown-in insulation pricing by R-value

R-value refers to how well a material resists heat transfer. The higher the R-value, the better the insulator. The recommended R-value depends on the insulated area and the geographical location. Colder climates require a higher R-value.

Blown-in insulation pricing by R-value
Blown-in material R-value per inch Cost per square foot installed
Fiberglass 2.2 – 2.9 $1.00 – $2.80
Cellulose 3.1 – 3.8 $1.20 – $2.80
Rockwool 3.2 – 4.1 $1.90 – $4.20

Insulation R-value recommendations
Insulation R-value recommendations

To determine the insulation depth needed, divide the required R-value for your space and region by the R-value of the insulation. The Department of Energy recommends:

  • Attics and ceilings: R-30 to R-60
  • Walls: R-13 to R-21
  • Floors and crawl spaces: R-13 to R-30

Loose-fill insulation cost by brand

The following table reflects the current loose-fill insulation cost for well-known brands.

Loose-fill insulation cost by brand
Brand Price per square foot* Material
American Rockwool $1.75 – $2.50 Rockwool
Applegate $0.25 – $1.50 Cellulose
Green Fiber $0.30 – $0.60 Cellulose
Johns Manville (JM) $0.40 – $0.80 Fiberglass
Nu-Wool $1.30 – $2.00 Cellulose
Owens Corning $0.30 – $0.60 Fiberglass

*Material cost for R-19 insulation; Labor not included.

Labor cost to blow in insulation

The labor cost to blow in insulation is $0.70 to $1.70 per square foot on average. Contractors charge $40 to $80 per hour, and installation takes 3 hours to 1 day or more, depending on the project size and site conditions.

Blown-in vs. batt vs. spray-foam insulation prices

Blown-in vs. batt vs. spray-foam insulation prices
Insulation type Average cost per square foot installed
Blown-in $1.00 – $2.80
Batt $0.80 – $2.60
Spray-foam $1.00 – $4.50
  • Blown-in insulation is the most cost-effective for homes where drywall is already in place and attics with oddly-shaped and hard-to-access areas.
  • Batt insulation costs $0.80 to $2.60 per square foot installed and is common in new construction wall cavities.
  • Spray foam insulation costs $1.00 to $4.50 per square foot, and its closed-cell variety is ideal for air sealing attics and crawl spaces.

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DIY blown-in insulation cost

DIY blown-in insulation costs $0.35 to $1.50 per square foot or $500 to $1,200 on average, depending on the insulation type and location. Blown-in insulation is a 2-person job—one feeding the blower and one directing the hose. Wet-spray blown-in insulation requires special equipment and is best left to pros.

  • Insulating existing walls involves drilling holes in the drywall and sealing and patching the holes after insulating.
  • Insulating the attic requires sealing any air leaks, boxing out light fixtures, and ensuring soffit vents are unobstructed. Adding ventilation may be necessary if any appliances or fixtures exhaust into the attic.

Blown-in insulation machine rental prices

Blown-in insulation machine rental costs $100 to $200 per day on average. Some home improvement stores provide free machine use when purchasing 10 to 20 or more insulation bags.

Follow the manufacturer's instructions when setting the machine's airflow. Setting the airflow too high results in an inaccurate R-value appearance due to overly fluffy insulation. Once it settles, the R-value may not be sufficient.

Frequently asked questions

What is blown-in insulation?

Blown-in insulation refers to small lumps of cellulose, fiberglass, or mineral wool fibers blown or sprayed into walls, attics, and floors. Cellulose and fiberglass are the most common blown-in insulation materials.

Pros and cons of blown-in insulation
Pros Cons
  • Increases energy-efficiency
  • Reduced energy costs
  • Quick installation
  • Noise reduction
  • Future selling point
  • Can be done without removing drywall
  • Fills in gaps and spaces too small for batt insulation
  • Possible rebates and tax incentives
  • Can be layered over existing batt insulation
  • Installation can be messy.
  • The attic must be air-sealed.
  • Installation requires 2 people.
  • Some installations require a professional.
  • Too much insulation may cause ceiling sag.
  • Susceptible to mold and rot if exposed to moisture
  • May settle over time

How long does blown-in insulation last?

Blown-in insulation lasts 20 to 30 years or more, depending on the insulation type, moisture levels, and whether it is disturbed. Blown-in insulation may degrade at 15 years in areas with extreme weather conditions. Increased utility charges are often a sign the insulation needs replacing.

Is blown-in wall insulation worth it?

Blown-in wall insulation is worth considering if your home is older and you plan to stay for at least five years. Insulating the walls is beneficial for sound dampening, added fire resistance, and improved indoor comfort. Insulating the attic is essential because most heat loss happens through the ceiling.

How much is a bag of blow-in insulation?

A 30-pound bag of blow-in insulation costs $30 to $40.

How much blown-in insulation do I need?

The amount of insulation needed depends on the type and R-value, area of the home being insulated, and local climate. Colder regions require higher R-values, meaning the insulation layer must be thicker.

Cellulose is denser and requires more bags per square foot than fiberglass to achieve the same depth. Still, its higher R-value per inch means that cellulose needs less depth to achieve the same total R-value.

Depth of material Minimum fiberglass bags* Minimum cellulose bags*
5 inches 7 16
10 Inches 14 32
15 Inches 21 48
18 Inches 26 57
20 Inches 29 63

*Approximate bags needed per 1,000 square feet.

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Getting blown-in insulation estimates and quotes

Before hiring an insulation company:

  • Get at least three quotes to compare.
  • Ask for a firm, itemized bid.
  • Look for pros experienced in blown-in insulation.
  • Browse their reviews on HomeGuide and Google.
  • Select companies that are insured, bonded, and have been in business for more than five years.
  • Ask for references.
  • Avoid selecting the lowest quote as quality may suffer.
  • Get a detailed estimate, contract, and warranty in writing before the work begins.
  • Never pay in full before the project starts. Use a payment plan instead for work completed.

Questions to ask blown-in installers

  • Are you licensed, bonded, and insured?
  • How long have you been in business?
  • What experience do you have with blown-in insulation?
  • Does the quote include removing damaged or old insulation?
  • Does the quote for attic insulation include air sealing?
  • Do you offer financing options?
  • Is there a warranty?
  • Can I be in the house during the insulation process?
  • How long will the project take?
  • How long should the insulation last?
  • Is there a warranty, and if so, what does it include?
  • What is and is not included in the price?
  • What additional costs should I expect?
  • Are there any rebates available, and do you apply for them?

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