Calculating blown-in insulation costs: DIY or call a pro?

HVAC Logo IconBy Tom MoorSeptember 18, 2023
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Create a more energy-efficient home with blown-in insulation. It’s a simple, affordable option that keeps your home warm during the winter and cool in the summer. 

Compare the cost difference between installing blown-in insulation yourself and relying on a pro. Cost data is courtesy of HomeAdvisor, Home Comfort Insulation, and The Home Depot.

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What is blown-in insulation? 

Blown-in, or loose-fill, is a dense variety of insulation. This thick insulation makes your home more comfortable. There are three types of blown-in insulation:

Fiberglass blown-in insulation is made small spun fibers of glass. The fibers bind together to create batts, which look like cotton candy. This is a good insulator for crawl spaces, attic floors, and other spaces.

Cellulose blown-in insulation is mostly made of recycled material, like newspaper. The crumbly material is covered in a fire-retardant chemical that makes the paper soft and helps it insulate well.

Rock wool, or mineral wool, insulation is made from volcanic rock. The rock is melted and spun into a thick material similar to fiberglass. Mineral wool is largely unaffected by moisture, is naturally fire retardant, and acts as a pest deterrent.

✅ Pros of blown-in insulation

  • Reduces noise levels throughout your home 
  • Traps in heat, promoting lower utility bills
  • Some varieties are fire-repellant, protecting your home from structural damage 
  • Insulates spaces that foam and fiberglass insulation don’t reach

❌ Cons of blown-in insulation

  • Challenging DIY project unless you’re experienced with insulation
  • Weight of blown-in cellulose can cause ceiling sag
  • Material is difficult to remove if it gets wet
  • Insulation settling can leave some unprotected spots in the walls

Where is blown-in insulation installed?

Blown-in insulation is installed in the walls of your home and the attic. Think of installing blown-in insulation like flossing your gums. Blown-in insulation fills in the gaps between the planks, where heat is most likely to escape.

Here are a few spots where blown-in insulation is installed:

  • Interior and exterior wall cavities: the space between the planks that give your walls support and structure. These planks are sometimes called studs.
  • Ceiling joist cavities: the space between the horizontal beams that support your ceiling.
  • Attic floor: Blown-in insulation on the attic floor can prevent conditioned air from escaping out the top of your home.

Blown-in insulation doesn’t hold up well in foundation or masonry walls. Rigid board foam and spray foam are better options, as they offer better moisture control.

Calculate the cost of blown-in insulation

The total cost of installing blown-in insulation depends on a number of factors. Think of fiberglass, cellulose, and rock wool blown-in insulation as a good, better, best tier. Fiberglass is the least expensive, while cellulose is middle-of-the-pack, and rock wool is the priciest.

Loose-fill fiberglass insulation cost

Loose-fill fiberglass costs $0.40 to $1.10 per square foot, on average. Pricing could vary greatly depending on your region. Labor cost for attic insulation ranges from $40 to $70+ per hour.

Cellulose insulation cost

Cellulose insulation costs $0.60 to $2.30 per square foot, depending on brand and quality. Again, pricing may differ for your region. Plus, insulation companies will charge by the hour to move items in your attic to complete the job. It’s a good money-saving option to remove anything in the attic ahead of insulation time.

Rock wool insulation cost

Rock wool insulation costs $1.40 to $2.10 per square foot, on average. While rock wool is the least used type, it’s highly flame-retardant. We recommend it for areas where fire code requirements should be followed, like the walls connecting your house to the garage.

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How to calculate blown-in attic insulation cost

Attics should be filled with dense insulation. Some states enforce a legal minimum R-value for attic insulation. 

We suggest Googling “[your state or city] attic insulation compliance guide” before buying any materials. If your city or state has no legal minimum R-value, this free guide from lists the suggested R-value for your climate.  

If you’re installing attic insulation yourself, first calculate the square footage of the attic space that needs insulation.

Divide the square footage of your ceiling joist cavities by the square footage covered per bag of insulation. Round up to the nearest whole number. The result is the number of bags of insulation you need to buy.

Let’s look at the estimated cost of materials to pad your attic with fiberglass vs. cellulose blown-in insulation. If you hire a professional, they will supply the correct amount of insulation.

Cost of fiberglass materials

Fiberglass costs about $33 per 25-pound bag, on average. The cost of materials to insulate 1,000 square feet of attic space varies from $429 to $1,056, depending on the R-value and brand of insulation.

Desired R-valueSquare feet covered per bagCost of materials (1,000 sq. ft) 
R3066-77$429 – 495
R3850-60$554 – 660
R4443-50$663 – 759
R4938-44$746 – 858

Cost of cellulose materials

A 25-pound bag of cellulose insulation costs anywhere from $15 to $30. The cost of materials to insulate a 1,000-square foot attic ranges from $641 to $2,256.

Desired R-valueSquare feet covered per bagCost of materials (1,000 sq. ft) 
R3013$641 – 1,282
R3815$840 – 1,680
R4418$993 – 1,986
R4923$1,128 – 2,256

How to calculate blown-in wall insulation cost

Blown-in wall insulation isn’t as thick or heat-resistant as attic insulation. Usually, wall insulation has an R-value between R-13 and R-24.

We recommend hiring a pro for the installation (more on that below). The pro will decide how many bags of insulation you need.

Cost of blown-in wall insulation materials

Here’s a breakdown of the estimated cost of materials for 1,000 square feet of wall space. Pricing reflects national averages and excludes labor costs. 

  • Fiberglass: $400 – 1,100
  • Cellulose: $600 – 2,300
  • Rock wool: $1,400 – 2,100 

Labor costs of blown-in insulation

Hiring a professional to install the insulation adds labor fees to the total cost. Labor costs range from $40 to $70 per hour, depending on your location and the time of year.

The charts below show the average labor time and cost by R-value. Depending on your attic or wall’s square footage, your final labor costs may vary.

Labor cost of attic insulation

Installing blown-in attic insulation can be a DIY project. It’s also relatively inexpensive to hire a professional for a job. Installation takes a half-day to a full day, depending on your square footage.

Labor costs average $160 to $560 in the U.S. Compared to wall insulation, attic insulation is less invasive and time-consuming to install.

Insulation R-valueLabor hours (per 1,000 sq. ft)Labor cost
R-304$160 – 280
R-385$200 – 350
R-446$240 – 420
R-497$280 – 490
R-608$320 – 560

Labor cost of wall insulation

Wall insulation is more expensive and time-consuming to install. Cutting a hole in the wall runs the risk of hitting a pipe or electrical wire, so a skilled professional is your best bet.

The labor cost of installing blown-in wall insulation averages $800 to $2,100. This range does not include the cost of materials and other service fees.

Insulation R-valueLabor hours (per 1,000 sq. ft.)Labor cost
R-1320$800 – 1,400
R-1523$920 – 1,610
R-2127$1,080 – 1,890
R-2430$1,200 – 2,100 

Finding a professional doesn’t have to be a hassle. Here are our tips for getting a quality job done at a reasonable price:

  • Get 3-5 quotes from local HVAC contractors before choosing one.
  • If you can, wait until the off-season in late fall or early winter. This season is generally a slow time for contractors, giving you the best chance of low wait times and labor costs.
  • Budget for about 15% more than our highest estimate. The HVAC market fluctuates, and prices change often.

Should you install blown-in insulation yourself?

Installing blown-in attic insulation can be a weekend DIY project for someone familiar with the work. Otherwise, hire a professional.

We don’t recommend installing blown-in wall insulation yourself. The pipes and electrical wiring behind the drywall are a safety hazard for inexperienced drillers. Go with a licensed and insured professional. 

Talk to an HVAC professional about insulating your home.

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Blown-in insulation machine rental cost

Home improvement stores usually rent out insulation blowers in 24-hour time slots. Nationally, daily rental costs $100 to $200.

Seasonal discounts and deals can reduce the machine rental cost. Some companies offer free 24-hour blower rentals when you buy insulation in bulk.

Installation toolkit

Installing blown-in attic insulation yourself? You’ll need these affordable, easy-to-find safety materials.

Check out our attic insulation guide for more DIY tips and tricks. 

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