How Much Does Blown-In Insulation Cost to Install?

Blown-In Insulation Cost per Square Foot

Blown-in insulation runs from $1 to $1.50 per square foot. Prices are contingent on R-value, the measurement used to determine how much heat will leave your home based on the thickness and quality of the spray insulation.

Your cost per square foot might increase depending on the area you're spraying. For example, adding insulation around electrical wiring or outlets will likely require the help of a pro, potentially exceeding the $1.50 per square foot price.

The cost to insulate an attic with blown-in insulation runs from $600 to $1,200, assuming it’s 1,000 square feet in size, which is standard for many American homes. This includes labor, which costs about $40 to $70 per hour.

The average U.S. household should shoot for a minimum R-value of 30 for blown-in insulation. This equates to 10 to 14 inches of material.

Blown-In Wall Insulation Pricing

Similarly, it costs about $1,000 to $1,500 to insulate 1,000 square feet of wall space. This job is complex and requires the insulation pro to work around drywall, wiring, outlets, and other structures. For these reasons, it can take several days to complete. Most experts recommend getting professional help for this project.

Here is a breakdown of pricing for blown-in wall insulation based on one manufacturer's specifications:

Blown-In Insulation Costs by Type

Choosing different types of blown-in insulation can increase the price based on the costs of raw material to make the insulation, plus different installation time frames. Below are some estimates per square foot.

Rockwool Fiber

Made from rock and slag fibers, Rockwool fiber is slightly more expensive than cellulose. Also called “mineral wool,” it costs $1.40 to $2.10 per square foot. 

Here are some benefits of mineral wool:

• Great acoustic control

• Naturally repels pests

• Noncombustible

• Highly heat insulative

• Repels moisture 

• Easy DIY project

• Sustainable and recyclable

Cellulose 

Blown-in cellulose is often more expensive than fiberglass and costs about $1.20 per square foot. The cellulose insulation cost per bag is typically around $30 to $40. It consists of recycled materials like newspaper and cardboard. The higher the R-value, the more you’ll pay for each project. Cellulose insulation comes in damp-spray and dense-pack options. 

While damp-spray cellulose doesn't appear as tightly pressed to walls as dense-pack, each material is rated similarly in terms of its insulation abilities. The difference often comes down to the manufacturer or insulation company you choose.

Wet Blown-In Cellulose

Damp-spray insulation runs from $0.60 to $1.80 per square foot to install. Wet installations, which are sprayed and typically have short dry times, work best for new constructions when additional projects are going on around the insulation work.

Like other forms of insulation, it's fire retardant. It costs slightly less than dense-pack cellulose because it takes longer to dry and may leave gaps if not installed professionally.

Dense-Pack Cellulose 

Dense-pack cellulose, which is air blown but dry when installed, is more costly at $2.00 to $2.30 per square foot when you hire a pro to install it. Because of its high R-value, it works best in older homes, which may be more susceptible to letting hot or cool air escape. The installation process is less disruptive to surrounding structures than wet installation, but it may take longer.

Fiberglass

Fiberglass insulation runs from $500 to $1,060 to cover 1,000 square feet. The price per job varies based on the R-value of the insulation and the size of the project. Unlike cellulose, there are many options to choose from. Blown-in insulation increases your home’s energy efficiency and can help save money over time.

For a bag weighing 28 1/2 pounds, at an average cost of $33 a bag, a breakdown of R-value, number of bags, and material cost appear in the following table.

Blown-In Insulation Cost Factors

From hiring a pro to the strength and thickness of your blown-in insulation, some factors change the price you pay for your insulation.

Labor

The cost of labor runs from $40 to $70 per hour. It costs more to install insulation in an older home than in a new one. Thicker insulation costs more because the raw materials are more expensive and it takes longer to install.

R-Value

The R-value of blown-in insulation depends on the material's density and insulating factors. The higher the R-value, the better the material's insulating ability and the higher the price.

The U.S. Department of Energy recommends the following levels of insulation:

• Floors and Crawl Spaces: R-13–R-30

• Walls: R-13–R-23

• Ceilings and Attics: R-30–R-60

Attics require higher R-values because heat rises. About one-quarter of a home’s heat escapes through the attic. As a result, the densest form of blown-in insulation should be in this part of a house. 

New Construction vs. Replacement

With new blown-in insulation, you've got labor and material costs to cover that you or your pro can estimate on a square-foot basis. Replacing insulation can be different because you're unlikely to spray vast areas with no insulation. Instead, you’re likely fill gaps and cracks, which will take less time and require fewer materials.

When installed properly, blown-in insulation is rated to last between 60 and 80 years.

Mold and Asbestos Remediation

It's a common misconception that mold can grow in blown-in insulation. However, mold and asbestos can form on top of dust or other particles if it falls from a roof or another object.

On average, mold removal costs$2,250, while asbestos removal costs $2,100. For safety reasons, a pro will not fix or add blown insulation until both are removed.

Repairs

Holes are often left behind when installing blown-in insulation. These holes allow for the natural expansion of the material and alleviate pressure. Fortunately, you can patch drywall using budget-friendly methods. You can use a small can of spray insulation to fill the hole, allow it to dry, and saw away any excess. Or simply cover it with putty and paint. You can use either method for under $30.

Brand

Loose-fill insulation manufacturers vary in specialty and cost. Some brands, like Blown-In-Blanket Insulation, can only be installed by a certified contractor. Keep in mind that costs differ based on the R-value of the material. Here are a few top brands and their prices.

How Much Blown-In Insulation Do I Need?

Here are the steps to calculate the number of bags of blown-in insulation you'll need for your project:

1. Measure the square footage of your project area.

2. Decide which R-value will work for the area(s) of the home you’re insulating.

3. Find the square footage covered by a bag of your chosen insulation.

4. Find the R-value of your chosen insulation.

5. If the R-value requirement of your home matches the R-value of your chosen insulation, then simply purchase enough insulation to cover the correct square footage (with some overage).

6. If the R-value of the insulation is less than what your home needs, add additional bags to get the correct R-value. Most manufacturers include a handy chart on the packaging to help you calculate the number of bags to buy.

"It's important to know your regional specifications when deciding how much insulation to install. While R-30 is standard for temperate areas, the Department of Energy recommends R-38,” says Cati O’Keefe, Expert Home Building & Sustainability Contributor. “Homeowners in parts of the country that experience extreme climate may need to insulate their attics to R-60."

Benefits of Installing Blown-In Insulation

Blown-in insulation is faster to install and less expensive than batt and roll, another form of insulation. You or your pro will have to unravel, measure, and cut batt and roll to fit each specific wall or section you’re reinforcing. 

Additionally, blown-in insulation adds longevity to roofs and shingles, decreases energy bills, and helps eliminate cold and hot spots in your house. It's also rated to last up to 100 years in some cases, making it a long-term investment for your home. 

DIY Blown-In Insulation vs. Hiring a Professional

If the project takes up a large surface area, involves electrical wiring or outlets, or is beyond your skill level, it’s best to hire an insulation pro near you to install the insulation quickly and safely. For smaller projects, less complicated spaces, or general touch-ups, DIY installation is possible. If you attempt to DIY, prepare for a learning curve and allow yourself some extra time.

Blown-In Insulation Machine Rental Prices

The cost to rent a blow-in insulation machine varies. On average, you can expect to spend around $100 to $200 for a 24-hour rental. Some insulation manufacturers offer machine rental for free with the purchase of their product. 

FAQs

What are the advantages of blown-in insulation?

In comparison to roll mats, blown-in insulation is fire-resistant and long-lasting. It’s also more energy-efficient and easier to install. 

How much does it cost to install blown-in insulation for a 1,500-square-foot house?

It costs between $1,500 and $2,250 to cover 1,500 square feet with blown-in insulation. If you hire a pro, remember to factor in labor costs.

How much does it cost to insulate a 1,200-square-foot attic with blown-in fiberglass?

You’ll pay about $950 for materials to cover 1,200 square feet with blown-in fiberglass. A pro will typically charge $40 to $70 per hour for labor.

What’s the cost of spray foam insulation vs. blown-in cellulose?

Spray foam insulation costs$0.45 to $1.50 per board foot. Blown-in cellulose is more expensive and costs $0.60 to $2.30 per square foot.

Is blown-in insulation cheaper than batts?

Batts are typically more expensive to install than blown-in insulation. Batt and roll insulation costsup to $2,500 on average. So you might save money by opting for blown-in.

What’s the best blown-in insulation R-value to get?

The best R-value for blown-in insulation depends on the area where you're adding insulation and your home’s needs. An average home attic in the U.S., for example, should have a minimum R-value of 30.