Ashburn, VA

How Much Does Blown-In Insulation Cost To Install?

$874 – $2,156 ($1.59 per square foot)

The average cost of blown-in insulation to achieve an R-value of R-38–R-49 is $1,665 with most homeowners spending between $874 and $2,156 or $1.59 per square foot. Get free estimates from insulation contractors near you.

Blown-In Insulation Cost

When you need to add insulation to an attic, crawl space, or walls of a home, the fastest and most cost-efficient method is to use blown-in insulation. The average cost of blown-in insulation to achieve an R-value of R-38–R-49 is $1,665 with most homeowners spending between $874 and $2,156 or $1.59 per square foot. This price does not include air sealing and ventilation which costs $350 to $1,500.

Average Cost Of Blown-In Insulation
National Average Cost $1,665
Minimum Cost $646
Maximum Cost $2,681
Average Range $874 to $2,156

Table Of Contents

  1. Blown-In Insulation Cost
  2. Blown-In Insulation Cost Per Square Foot
  3. Attic Insulation Costs
  4. Blown-In Insulation Walls & Floors
  5. Why Use Blown-In Insulation?
  6. Blown-In Insulation vs. Batts
  7. Types of Blown-In Insulation
  8. DIY Blown-In Insulation
  9. Insulation Contractors Near Me

Pre-installation prices for the most common types of blown-in insulation are $0.83 per square foot for Cellulose, and $0.91 per square foot for Fiberglass. Therefore, 1,200 square feet of Cellulose insulation costs between $874 – $1,127, while Fiberglass costs between $950 – $1,244.

Blown-In Insulation Cost Per Square Foot
Insulation Type Cost Per Square Foot
Cellulose $0.83
Fiberglass $0.91
Mineral Wool $1.02
Wool Fiber $5.44

Average costs of blown-in insulation for a 1,200 square foot area with an R-38–R-49*:

Insulation Type Cost Per Square Foot
Cellulose $874 – $1,127
Fiberglass $950 – $1,244
Mineral Wool $1,064 – $1,372
Wool Fiber $5,700 – $7,350
*The R-value of an insulation material dictates how good the level of insulation is in the home. The US Department of Energy recommends an R-value of R-38 in most southern climates and R-49 in northern climates.

Blown-In Cellulose Insulation Costs

Cellulose is an eco-friendly option, made from recycled newspapers with added borate to make it fire and insect resistant. It has an R-value of 3.6 to 3.8 per inch. When blown in at a proper fill rate, it will not settle. It is also irritant free, although you should still use the proper safety equipment to protect your lungs from dust and your skin from any possible reactions.

A bag of cellulose blown-in insulation costs $11.47–$11.81 at Lowes. The following chart is based on a 1,200 square foot home, insulating the attic only. We’re using a labor cost average of $15 per bag.

Blown-In Cellulose Insulation Costs
R-Value Coverage Per Bag # of Bags Material Cost Labor Cost
19 36.7 sq. ft. 32 $328 $480
30 21.70 sq. ft. 56 $661 $840
49 12 sq. ft. 100 $1,181 $1,500

Buy by the pallet for larger homes.[1]

Product R-Value Coverage Per Pallet # of Bags Cost
Green Fiber All Borate Cellulose R19 2,160 sq. ft. 36 $448
Green Fiber Low Dust Cellulose R19 2,160 sq. ft. 36 $509
TAP EPA Registered Pest Control R19 2,160 sq. ft. 36 $548

Blown-In Cellulose Insulation

Blown-in Fiberglass Insulation Costs

Fiberglass is the most common and least expensive material used to insulate attics. Blown-in fiberglass insulation doesn’t settle after time has elapsed, so if you blow in 16.5” of fiberglass, it will remain at 16.5” of fiberglass.

A bag of Knauf Insulation EcoFill Wx Fiberglass Blown-in Insulation costs $31.54–$38.86 at Home Depot, depending on prices at your local store. The following chart is based on a 1,200 square foot home, insulating the attic only. Labor costs vary depending on the machinery used and number of workers. Here we use a labor cost average of $15 per bag.

Blown-In Fiberglass Insulation Costs
R-Value Coverage Per Bag # of Bags Material Cost Labor Cost
R-19 106.6 sq. ft. 12 $466 $180
R-30 65.5 sq. ft. 19 $738 $285
R-49 38 sq. ft. 32 $1,244 $480

Blown-In Fiberglass Insulation In Attic

Blown-In Rockwool & Mineral Wool Costs

Made from slag, rockwool or mineral wool insulation mostly only comes in batts, but Owens Corning has a specialty blown-in product called Thermafiber INSUL-FILL, and American Rockwool offers Rockwool Premium Plus™ Insulation. It’s less available in blown-in form and few residential insulation contractors offer it.

Popular in Europe, blown-in rockwool is making a steady comeback in the US due to its low health risks, higher R-value, higher sound absorption, and fire and mold-proof features. It’s priced between cellulose and fiberglass at about $0.33–$0.37 per square foot covered. [2]

Blown-In Mineral Rock Wool Insulation In House Attic

Blown-In Natural Wool Insulation Costs

Sustainable, biodegradable, and renewable, wool insulation uses about 10% of the energy it takes to produce fiberglass insulation. [3] It also won’t grow mold, has incredible sound absorption, and is nontoxic and hypo-allergenic. A 25 lb. bag of Havelock Wool Loose Fill Insulation is $140.[4] For a 1,200 sq. ft. home,

Blown-In Wool Insulation Costs
R-Value Coverage Per Bag # of Bags Material Cost Labor Cost
19 60 sq. ft. 21 $2,940 $315
30 38 sq. ft. 32 $4,480 $480
49 23 sq. ft. 52 $7,280 $780

This loose-fill insulation can be blown in using various blowing machines or can be filled by hand. Because it’s nontoxic and completely natural, there is no need for safety precautions when installing it.

Attic Insulation Costs

Two technicians can install attic insulation in about two to four days, depending on the R-value you want them to build it to. Adding to or increasing the amount of insulation in your attic will help your home to stay warmer or cooler and it can reduce your utility bills by 15%–25%. Over time, the cost of insulating the attic (and other spaces) will pay for itself. When calculating attic insulation costs for 1,200 square feet, the average homeowner pays:

  • $528 – $946 for materials
  • $380 – $1,210 for labor
  • For a total of $908 – $2,156

Depending on the amount of air sealing and ventilation that needs to be done, expect to add $350–$1,500 to your final cost.

Attic Insulation Energy efficiency measuring the thickness of fiberglass insulation in the attic

Attic Insulation Cost Factors

  • Size of Sttic – more square feet will use more insulation material and take longer, costing more in labor.
  • Current insulation levels – How much you already have will dictate how many more inches you need.
  • Air Sealing – Air leaks are a major cause of losing warm air. Typically, the cost for air sealing runs from $350 to $1,500. If you have a complex attic with lots of ductwork, bathroom fans, and ceiling fixtures, more air sealing will need to be done. Use expanding foam or caulking to seal any air leaks in your attic. A furnace or water heater flue in the attic requires an insulation dam around it, usually of 1 inch.
  • Blown-in insulation machine rental – If doing it yourself, you’ll have to pay for machine rental.
  • Labor – If hiring someone else, you’ll pay about $37–$65 per hour or $15 per bag for the labor and any additional costs. It takes one person about 25 minutes to blow one bag of insulation into the attic. The number of days for project completion depends on how many workers are present.
  • Materials chosen – there’s a huge difference in price between the oft-used cellulose and fiberglass vs. natural wool per square foot.

Blown-In Insulation Walls and Floors Cost

Because of the space between the drywall in one room to the next, you won’t be able to have the same depth of insulation in your walls as you can in your attic, so at most you’ll only be able to have an R-value of 24. Nevertheless, you can fill the entire space with the filling of choice and still reduce your heat and noise extremes considerably. Because filling walls and floors is a more complex process involving cutting out holes to insert the blowing machine tube in various places, it’s best done by a professional. Prices from Blown In Insulation are as follows: [5]

Walls & Floors Insulation Costs
2,200 Sq. Ft. Home R-Value # of Bags Labor Hours Cost
Floors
Fiberglass

R-19
R-21

29
29

30
30

$1,437
$2,253
Walls
Cellulose
Fiberglass

R-19
R-21

75
47

27
27

$886
$1,551

R-value And Insulating Capacity

The cost of the job will depend on the amount of blown-in insulation R-value used or how much R-value you desire. R-value is defined as a material’s ability to slow the heat traveling through it. The higher the R-value, the more it slows the escaping heat and the better your home is insulated. Recommended R-values run from R25–R60, depending on the climate where you live. Very cold climates need a higher R-value.

Why Use Blown-In Insulation?

  • Energy savings – Heat rises, and much heat can be lost through the ceiling and into the attic, where it makes its way to the outside. It also escapes through walls and flooring. Keeping energy in will reduce the work expended by your HVAC system, saving you about 25% off your usual energy bills.
  • Fire and pest retardant – treated with various types of fire retardants and pest control chemicals.
  • Doesn’t absorb moisture – thus avoiding rot and mold issues.

Energy Efficiency Rebates and Loans

Most states and energy companies offer a rebate program and tax credits on insulation installation costs. For instance, Columbia Gas offers a rebate amount of

  • Attic Insulation (Replacement): $0.15/sq. ft.
  • Multi Family Attic Insulation: $0.13/sq. ft.
  • Floor Insulation (Replacement): $0.40/sq. ft.
Some cities offer loans with low interest rates if you achieve a 20%–25% efficiency improvement in the home, to include attic insulation of at least R=38.[6]

Blown-In Insulation vs. Batts

If you’re planning to add insulation to an existing structure, blown-in insulation is the best way to go. You don’t want to remove drywall to install rolls of fiberglass insulation; in fact, you want to disturb your home as little as possible.

It is also preferable to use blown-in insulation instead of batts (rolls), because the very act of blowing in the fiberglass or cellulose pieces causes them to create a seamless blanket, much like a blanket of snow. If you were to use batts/rolls of insulation, it would need to be cut precisely around the joists, wiring, ductwork, and any other inconsistencies that make up your attic. If not cut precisely, it creates air leaks, which work at cross purposes to the insulation you just installed.

Blown-in insulation can be added to exterior walls quite easily. A panel of siding is removed and a 3” hole is drilled. Insulation is blown in, densely packing the area between studs. The hole is plugged and sealed, and the siding is replaced. There are no rows of plugged circles to give away the fact that you’ve just added insulation.

Types of Blown-In Insulation

We are going to compare fiberglass vs. cellulose vs. rock wool fiber and include advantages and disadvantages of each:

Fiberglass Insulation

Blown-in fiberglass is made of tiny strands of glass. If inhaled, they can cause sickness, and if they land on your skin, itchiness and rashes are the result. It’s also a carcinogen. Be fully prepared to handle this material with the safety equipment necessary to protect your eyes, lungs, and skin.

Advantages of Fiberglass:

  • Fiberglass will not burn, making it safer in a fire
  • The tiny particles fill in the area completely, especially the tiny cracks and crevasses
  • Particularly good at reducing noise problems
  • Easy to install
  • Contains no allergens
  • The barrier it creates also keeps out pollens, pollutants, and other airborne toxins
  • Can be a DIY project, but can be done quickly and efficiently by a professional
  • Is not affected by moisture
  • Is a good sound barrier

Disadvantages of Fiberglass:

  • Allergens, dust, and moisture can be trapped by particles of fiberglass, leading to the growth of mold.
  • Fiberglass particles float in the air when disturbed. This leads to inhalation of fiberglass which can cause coughing, respiratory problems, and nosebleeds. The particles can also land on your skin, which causes rashes and painful itchiness.
  • Rolls of fiberglass still allow airflow because the edges of the rolls do not meet exactly; there are gaps. This results in a loss of warm air, causing your energy bills to go up.
  • When working in the attic filled with fiberglass, protective clothing must be worn—gloves, goggles, long-sleeve shirts, and long pants ($5.50 for 3 masks).
  • Mice and rats will still nest in it.

Cellulose Insulation

Cellulose is mostly made up of recycled newspaper treated with borate to make it fire and insect resistant. It’s not fireproof, but it will give you and your family some extra escape time if the unthinkable happens. The borate also repels mice and other rodents. If cellulose becomes wet, perhaps due to burst pipes, it must be cleaned up. This is a big job and preferably done by professionals from a water damage restoration company.

Advantages of Cellulose:

  • It’s a recycled product, with 80%–85% recycled newspapers making up the bulk of the insulation. This makes it eco-friendly.
  • It’s reasonably priced.
  • Fills the nooks and crannies of the attic without any tricky cutting
  • Has a higher R-value than other blown-in insulations
  • Nontoxic and has no known health side effects
  • Can be a DIY project but can be done quickly and efficiently by a professional
  • Rats and mice don’t like to nestle in it.

Disadvantages of Cellulose:

  • When blown into the attic, it can settle or even be moved by small air leaks over time. This will leave the attic unevenly insulated. Check your attic from time to time to see if the cellulose needs raking to even it out.
  • If cellulose becomes wet, it absorbs up to 130% water, making it a possible weight problem over your head, as well as a mold/mildew problem.
  • Cellulose can settle by up to 20%, meaning more insulation will need to be added at a later date.
  • If you have a home furnace duct system, cellulose dust can be recirculated through that furnace—something to be aware of if you have family members with allergies or breathing problems.
  • If it does get wet, it will dry very slowly. The water will also destroy the borate, taking away the fire- and pest-resistant qualities. As it dries, it will also settle, causing the need for more insulation.

RockWool & Mineral Wool Insulation

RockWool Fiber is also eco-friendly, being made from slag, which is what’s leftover after making steel. It’s more like fiberglass than cellulose, right down to the itchy factor. It’s made by melting down basalt stone and combining it with slag. Then it’s spun into fibers that form rigid batts or boards. It’s less available in blown-in form—almost a rare find. Used mainly in Europe and Canada, it is starting to be used in the United States with more regularity.

Advantages of Mineral Wool:

  • Can take the heat, thus, it’s a great insulator around the hot places in your attic, like the fireplace or heating ducts.
  • Absorbs sound extremely well
  • Has a higher R-value than blown-in fiberglass or cellulose
  • Does not absorb water. If you have a roof leak, the rock wool will remain exactly the same after the water is gone.
  • Denser than other insulations; excellent for sound control
  • Price wise, it falls between fiberglass or cellulose.

Disadvantages of Mineral Wool:

  • Protective clothing must be worn while installing or working around rock wool insulation. The tiny fibers can settle on skin, causing irritation. They can also be inhaled, whereby they lodge in the lungs, causing respiratory ailments. Some studies even show cancer has been traced back to rock wool insulation.
  • It is not as readily available as fiberglass or cellulose.

Natural Wool Insulation

The most eco-friendly insulation possible, the only downside to insulating walls or attics with wool is its cost.

Advantages of Natural Wool:

  • Depending on processing methods, it has few harmful chemicals
  • Hypoallergenic
  • Absorbs and releases moisture and won’t grow mold
  • Absorbs 90%–95% of airborne sound

Disadvantages of Natural Wool:

  • Seven to nine times more expensive than fiberglass or cellulose
  • Organophosphates used to treat possible scab mite infestations in the wool during processing might be in the wool, and they can cause neurophysical health problems. Check processing methods of the wool insulation you choose.

DIY Blown-In Insulation

Required Tools

You will need some specific tools if you’re going to do this project yourself. Most importantly, you’ll need the blower. Some stores will let you use the blower at no cost when you purchase a certain amount of insulation from them (free 24-hour rental with the purchase of 10 bags of insulation at the Home Depot).

If you can’t get a deal on a blower, you can rent one for about $75 a day. If you are well-prepared to do this job, you’ll have all your tools assembled and all materials within reach so you can finish using the blowing machine in less than a day and do all the wrap-up work on the following day.

Other needed tools are:

  • Hole saw
  • Drill
  • Dust Mask
  • Safety Glasses
  • Work Gloves
  • Tape Measure
  • Utility Knife
  • Spackle knife
  • Ladder

Required Materials

  • Bags of insulation
  • Spackle
  • Expanding foam to seal air leaks
  • Ventilation materials

Before you can start blowing in the insulation, you must seal the air leaks and make sure the attic has proper ventilation—this will protect you from moisture buildup, which in turn causes mold and mildew situations.

Be prepared with all the proper safety equipment. You’ll need a hard hat if you’re working in the attic to protect your head from roofing nails that might be poking through.

Selecting Your Insulation Contractor

Adding blown-in insulation to your existing home is an excellent way to lower your monthly utility bills and become more energy efficient. It is an investment that will pay off in the long run.

Get free estimates on HomeGuide from trusted insulation companies:

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[1] Home Depot prices

[2] http://www.americanrockwool.com/_docs/rwpp/Insulation%20Comparison%20Presentation.pdf

[3] http://oregonshepherd.com/products/

[4] https://havelockwool.com/loose-fill-insulation/

[5] http://www.blownininsulationcost.net/calculating-blown-in-insulation-cost/

[6] https://www.energy.gov/savings/city-plano-smart-energy-loan-program

Author: Daniel W.
Millions of people ask HomeGuide for cost estimates every year. We track the estimates they get from local companies, then we share those prices with you.

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